Duplicate data costs businesses time, money, and accuracy. One duplicate entry can inflate your metrics by thousands, send multiple invoices to the same customer, or crash your analysis.

In this guide, we show you 5 proven methods to remove duplicates in Excel. From the simplest one-click solution to advanced automation for large datasets.

Quick Answer: Remove Duplicates in 3 Clicks

The fastest way to remove duplicates in Excel:

1. Select your data range (including headers)
2. Go to Data tab → Remove Duplicates button
3. Choose columns to check → Click OK

Excel instantly deletes duplicate rows and shows you how many were removed.

But there’s more: This method has serious limitations with large files, multiple spreadsheets, or complex business rules. We’ll cover all scenarios below, including what to do when Excel can’t handle your data volume.

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Method 1: Remove Duplicates Button (Fastest)

Excel’s built-in Remove Duplicates feature is the quickest way to clean your data. It permanently deletes duplicate rows in seconds.

Step-by-Step Instructions

Step 1: Select Your Data

• Click any cell inside your data table
• Excel automatically detects the entire range
• Or manually select the range with your mouse

Pro tip: Make sure to include your header row for clarity.

Step 2: Open Remove Duplicates

• Navigate to Data tab in the ribbon
• Click Remove Duplicates button (Data Tools group)
• Keyboard shortcut: Alt + A + M

Step 3: Choose Comparison Columns

• Excel displays all column names with checkboxes
• Check “My data has headers” if your first row contains column names
• Select which columns to check:
  • All columns checked = entire row must match
  • Specific columns only = matches based on those fields only

Step 4: Execute Removal

• Click OK
• Excel displays: “X duplicate values found and removed; Y unique values remain”
• Click OK to dismiss the message

What Gets Deleted?

Critical: Excel keeps the first occurrence and deletes all subsequent duplicates.

Example:

Row 5: John Smith | john@email.com | 555-1234
Row 12: John Smith | john@email.com | 555-1234  ← DELETED
Row 18: John Smith | john@email.com | 555-1234  ← DELETED

Row 5 stays; rows 12 and 18 are permanently removed.

When to Use This Method

✅ Best for:

• Clean, structured data in a single Excel file
• Under 100,000 rows
• When you want permanent deletion
• Exact duplicate matches

❌ Don’t use when:

• You need to keep the original data
• Working with 500K+ rows (extremely slow)
• Deduplicating across multiple Excel files
• Need to keep “last” occurrence instead of first

Limitations

Performance: Dramatically slows above 100K rows:

• 100K rows: 30-60 seconds
• 500K rows: 3-5 minutes (may crash)
• 1M+ rows: Often fails entirely

No Flexibility:

• Always keeps first, never last
• Can’t keep “most complete” record
• No fuzzy matching
• Permanent deletion (risky without backup)

Single File Only: Cannot deduplicate across multiple Excel files without manually consolidating them first.

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Method 2: Advanced Filter (Keep Originals)

Use Advanced Filter when you want to preserve your original data and copy unique records to a new location for review.

Step-by-Step Instructions

Step 1: Select Your Data Range

• Click any cell in your data table
• Excel auto-detects the range

Step 2: Open Advanced Filter

• Go to Data tab → Sort & Filter group
• Click Advanced button

Step 3: Configure Filter Settings

• Select “Copy to another location” (not “Filter the list, in-place”)
• List range: Auto-filled with your data range
• Copy to: Click an empty cell where results should appear
• Check: “Unique records only”
• Click OK

Result

Excel copies all unique records to your specified location. Your original data remains completely unchanged.

When to Use Advanced Filter

✅ Best for:

• Preserving original data for audit trails
• Side-by-side comparison (originals vs. uniques)
• Uncertain about which duplicates to keep
• Testing deduplication logic before committing

❌ Limitations:

• Doubles memory usage (copies all data)
• Still limited by Excel’s 1,048,576 row maximum
• No control over which duplicate to keep (keeps first)
• Slower than Remove Duplicates button

Advanced Filter vs. Remove Duplicates

Feature	Advanced Filter	Remove Duplicates
Preserves originals	✅ Yes	❌ No (deletes)
Speed	Slower	Faster
Memory usage	2x (copies data)	1x
Undo after saving	✅ Yes (originals intact)	❌ No

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Method 3: Conditional Formatting (Visual Review)

Conditional formatting highlights duplicates without deleting them. Perfect for manual review before removal.

Step-by-Step Instructions

Step 1: Select Data Range

• Highlight the column(s) you want to check
• For entire table: Click top-left corner cell selector

Step 2: Apply Duplicate Highlighting

• Home tab → Conditional Formatting
• Highlight Cells Rules → Duplicate Values

Step 3: Choose Formatting

• Default: Light Red Fill with Dark Red Text
• Or select custom formatting color
• Click OK

Step 4: Review and Manually Delete

• Excel highlights all duplicate cells
• Review each highlighted row
• Manually delete rows as needed

Highlight Entire Duplicate Rows (Not Just Cells)

To highlight complete rows containing duplicates:

1. Select your entire data range
2. Home → Conditional Formatting → New Rule
3. Choose “Use a formula to determine which cells to format”
4. Enter formula: =COUNTIF($A:$A,$A1)>1
   • Replace $A:$A with your key column reference
5. Click Format button → Choose fill color
6. Click OK twice

When to Use Conditional Formatting

✅ Best for:

• Small datasets requiring manual judgment
• When some duplicates should be kept
• Learning which rows are duplicates before deletion
• Quality control and data review processes

❌ Don’t use when:

• Working with 10,000+ rows (too many to review manually)
• Need automated, repeatable process
• Duplicates must be deleted permanently

Pro Tips

Find duplicates in specific columns only: Modify the COUNTIF formula to check multiple columns:

=COUNTIFS($A:$A,$A1,$B:$B,$B1)>1

This checks if both Column A AND Column B are duplicated.

Highlight first occurrence differently: To mark ONLY subsequent duplicates (not the first):

=COUNTIF($A$1:$A1,$A1)>1

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Method 4: COUNTIF Formula (Custom Logic)

Use formulas when you need flexible, custom deduplication rules beyond Excel’s built-in tools.

Basic Duplicate Detection Formula

Add a helper column to flag duplicates:

=COUNTIF($A$2:$A2,$A2)>1

How it works:

• Place formula in cell B2 (assuming data in Column A)
• Drag formula down to all rows
• Returns TRUE if duplicate, FALSE if unique

Keep Only First Occurrence

To identify the first instance only:

=COUNTIF($A$2:$A2,$A2)=1

Returns TRUE for first occurrence, FALSE for all duplicates.

Multi-Column Duplicate Detection

Check duplicates across multiple columns (e.g., Email AND Phone):

=COUNTIFS($A$2:$A2,$A2,$B$2:$B2,$B2)>1

Example use case: Flag duplicate customers only if BOTH email and phone number match.

Complete Deduplication Workflow with Formulas

Step 1: Add Helper Column

Column C: =COUNTIF($A$2:$A2,$A2)=1

Step 2: Filter for Unique Records

1. Select all data including helper column
2. Data → Filter
3. Click dropdown on helper column
4. Check only “TRUE”

Step 3: Copy Results

1. Select visible (filtered) rows
2. Copy (Ctrl+C)
3. Paste to new sheet
4. Delete helper column

Advanced: Keep Most Recent Duplicate

To keep the newest record instead of first:

Step 1: Add helper column

=IF(COUNTIFS($A:$A,$A2,$D:$D,">"&$D2)>0,"Delete","Keep")

Assumes Column A = Email, Column D = Date

Step 2: Filter and delete rows marked “Delete”

When to Use Formulas

✅ Best for:

• Custom business logic (keep newest, most complete, highest value)
• Multi-column deduplication criteria
• Audit trail requirements (formula shows logic)
• Complex conditional rules

❌ Don’t use when:

• Simple deduplication (use Remove Duplicates button)
• Not comfortable with Excel formulas
• Need fully automated process

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Method 5: Power Query (Best for Large Data)

Power Query handles what Excel’s basic tools cannot: large datasets, repeatable workflows, and multi-file deduplication.

What is Power Query?

Built-in Excel feature (Excel 2016+) that:

• Processes millions of rows without crashing
• Automates repetitive deduplication tasks
• Combines multiple files automatically
• Refreshes with one click when source data updates

Step-by-Step Instructions

Step 1: Load Data into Power Query

• Select your data range
• Go to Data tab → Get & Transform Data group
• Click From Table/Range
• If prompted, check “My table has headers” → Click OK

Power Query Editor opens in a new window.

Step 2: Remove Duplicates

• Right-click the column header you want to deduplicate
• Select Remove Duplicates

Or for multiple columns:

• Select multiple column headers (Ctrl+Click)
• Right-click → Remove Duplicates

Step 3: Load Results Back to Excel

• Click Close & Load (top-left corner)
• Clean data appears in new Excel sheet

Refresh When Source Data Changes

After removing duplicates with Power Query:

1. Update your source data (add new rows)
2. Right-click the query table → Refresh
3. Power Query re-runs deduplication automatically

Advanced: Combine and Deduplicate Multiple Files

Scenario: You have 50 regional Excel files with overlapping customer records.

Solution:

1. Place all Excel files in one folder
2. Data → Get Data → From File → From Folder
3. Browse to folder → Click OK
4. Click Combine → Combine & Transform Data
5. Power Query loads all files
6. Remove duplicates across entire combined dataset
7. Click Close & Load

Result: All 50 files combined and deduplicated in minutes.

When to Use Power Query

✅ Best for:

• 100K+ rows (handles millions efficiently)
• Repeating the same deduplication monthly/weekly
• Combining multiple Excel files before deduplicating
• Need refreshable, automated workflows
• Complex transformation sequences

❌ Don’t use when:

• One-time quick cleanup (use Remove Duplicates button)
• Very small datasets (under 1,000 rows)
• Unfamiliar with Power Query (learning curve)

Power Query vs. Remove Duplicates

Feature	Power Query	Remove Duplicates
Max rows	Millions	1M (crashes before)
Speed (500K rows)	10-15 seconds	3-5 minutes
Multi-file support	✅ Yes	❌ No
Refreshable	✅ One-click refresh	❌ Manual re-run
Learning curve	Moderate	None

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When Excel Fails: Large-Scale Deduplication

Excel’s Breaking Points

Excel crashes or slows dramatically when:

Volume limitations:

• 100,000+ rows: Noticeably slower (30+ seconds)
• 500,000+ rows: Minutes to process, frequent crashes
• 1,000,000+ rows: Often freezes or fails completely

Real customer scenario:

“We had 200 Excel files with duplicate customer records across 19 countries. Manual deduplication took 4+ hours every week. Excel would crash when trying to open some files. We couldn’t keep up.”

— Financial Services Company, 20K employees

Complexity limitations:

• ❌ Cannot deduplicate across multiple Excel files simultaneously
• ❌ Cannot prioritize which duplicate to keep (always first)
• ❌ No fuzzy matching (“Microsoft Corp” ≠ “Microsoft Corporation”)
• ❌ Limited to exact character-for-character matches only

The Excel Workaround Problem

Manual multi-file deduplication:

1. Copy all files into one master Excel file (hope it doesn’t crash)
2. Run Remove Duplicates on master file (10-30 minutes)
3. Manually split back into regional files (hours of work)
4. Repeat weekly/monthly → Unsustainable

Deduplication with Mammoth

When Excel can’t handle your needs, Mammoth process millions of rows in seconds.

Key capabilities Excel lacks:

1. Multi-file deduplication

• Process 200+ Excel files simultaneously
• Consolidate and dedupe in one operation
• Example: “Remove duplicates across all regional sales files”

2. Custom keep strategies

• Keep most recent: MAX(Last_Updated)
• Keep most complete: Fewest NULL values
• Keep by priority: “HQ system beats branch systems”
• Business rules: “Keep highest transaction value”

3. Fuzzy matching

• “Microsoft Corp” = “Microsoft Corporation” = “MSFT”
• AI-powered similarity detection
• Handles typos, abbreviations, variations

4. Industry-specific deduplication

From app_tasks.txt (real customer implementations):

Financial Services:

• Customer deduplication across 19 countries
• Transaction duplicate detection
• KYC data standardization

Retail:

• Customer master data cleanup
• Order deduplication
• Product catalog consolidation (247 variations → 12 categories in 3 minutes)

Manufacturing:

• Part master cleanup
• Supplier deduplication
• Production data quality

Healthcare:

• Patient matching
• Procedure deduplication
• Billing record cleanup

Performance Comparison

Task	Excel	Mammoth
50K rows, single file	5 seconds	2 seconds
500K rows, single file	3-5 minutes	5 seconds
200 files, 1M total rows	Hours (manual) or crashes	15 minutes automated
Fuzzy matching	Not possible	Built-in
Keep “most recent” record	Manual sort workaround	One checkbox

Mammoth: Automated Multi-File Deduplication

When Excel’s manual process becomes unsustainable, Mammoth automates what takes hours down to minutes.

The Time Cost of Manual Deduplication

Excel’s manual process for 50 regional files:

1. Open File 1, copy data (2 min)
2. Paste into master file (1 min)
3. Repeat 50 times (150 minutes)
4. Remove duplicates with potential crashes (5 min)
5. Review results (30 min)
6. Manually split back to regional files (2 hours)

Total: 5+ hours every week
Annual cost: 260 hours = 6.5 work weeks

With Mammoth automation:

1. Upload 50 files (30 seconds)
2. Run saved deduplication pipeline (1 minute)
3. Export clean files (1 minute)

Total: 2.5 minutes weekly
Annual savings: 257 hours

How Mammoth Solves Multi-File Deduplication

1. Upload Unlimited Files Simultaneously

Instead of manually opening and copying files one by one:

• Drag and drop all regional files into Mammoth
• System automatically combines them
• No file size limits or crash risks
• Process millions of rows without performance issues

2. Visual JOIN Interface

No complex formulas or VBA required:

• Use JOIN task to match records across all files
• Click to select comparison columns (Customer_ID, Email, Phone, etc.)
• See duplicate matches instantly across your entire dataset
• Works like Excel’s Remove Duplicates, but across unlimited files

3. Custom Keep Strategies

Excel always keeps the first occurrence. Mammoth lets you choose:

• Most recent: Keep record with MAX(Last_Updated) date
• Most complete: Keep record with fewest blank fields
• Highest value: Keep customer with largest SUM(Transaction_Amount)
• Business rules: “HQ system data overrides branch system data”
• Custom logic: Any combination of conditions you need

4. AI-Powered Fuzzy Matching

Excel requires exact character-for-character matches. Mammoth detects variations automatically:

• “Microsoft Corp” = “Microsoft Corporation” = “MSFT”
• “John Smith” = “J. Smith” = “Smith, John”
• Handles typos, abbreviations, different formatting
• Adjustable similarity threshold (80%, 90%, 95%)
• Works across multiple columns simultaneously

5. Build Once, Reuse Forever

The biggest time-saver for recurring deduplication:

• Build your deduplication pipeline once (15 minutes)
• Save it as a reusable template
• Next week: Upload new files → Click “Run” → Done in 2 minutes
• Schedule automatic runs (daily, weekly, monthly)
• Never rebuild the same process manually again

Real Customer Results

Financial Services (MUFG):

• Challenge: 23% duplicate customer records across 19 countries
• Manual Excel process: Impossible to manage at scale
• After Mammoth: 0.7% duplicates with automated cleanup
• Impact: Improved regulatory compliance, eliminated manual effort

Manufacturing Company:

• Challenge: Weekly supplier data deduplication across multiple sources
• Before: 4 hours weekly manual Excel work
• After: 15 minutes automated in Mammoth
• Annual savings: 182 hours (4.5 work weeks)

Retail Organization:

• Challenge: 247 product name variations causing inventory errors
• Manual Excel cleanup: Days of work each quarter
• Mammoth fuzzy matching: 12 standardized categories in 3 minutes
• Result: Clean product catalog, accurate reporting, eliminated analysis errors

Mammoth vs. Excel Deduplication

Feature	Excel Manual	Mammoth
Single file (50K rows)	10 seconds	5 seconds
50 files (1M total rows)	4-5 hours manual	2 minutes
Fuzzy matching	Not possible	Built-in AI
Custom keep rules	Manual sort workaround	One-click selection
Repeatable process	Rebuild manually each time	Build once, reuse forever
Schedule automation	No	Yes (daily/weekly/monthly)
Learning curve	Already know Excel	15-minute setup
File size limits	Crashes at ~500K rows	Handles millions
Audit trail	No record of changes	Complete deduplication log

When to Consider Automated Deduplication

Excel works fine for occasional, single-file deduplication. Consider Mammoth when you:

• ✅ Deduplicate 10+ files weekly or monthly
• ✅ Work with 100K+ total rows across files
• ✅ Need fuzzy matching for name/company variations
• ✅ Want custom business rules (keep newest, most complete, highest value)
• ✅ Require audit trails showing what was deduplicated and when
• ✅ Your team spends 2+ hours weekly on manual deduplication
• ✅ Need to schedule automatic deduplication runs

The deduplication pipeline you build in Mammoth becomes a permanent asset. Next month’s data? Simply upload new files and run. No rebuilding, no formulas, no manual work.

Real Customer Results

Manufacturing company:

• Before: 4 hours weekly Excel deduplication
• After: 15 minutes automated
• Savings: 182 hours/year

Financial services (MUFG):

• Before: 23% duplicate customer records across 19 countries
• After: 0.7% duplicates with automated cleanup
• Impact: Improved compliance, reduced manual effort

Retail company:

• Before: 247 product name variations causing analysis errors
• After: 12 standardized categories
• Time: 3 minutes (vs. days of manual work)

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Common Deduplication Scenarios {#common-scenarios}

Scenario 1: Email List Cleanup

Problem: Newsletter list has duplicate email addresses

Solution:

1. Select email column
2. Data → Remove Duplicates
3. Check ONLY “Email” column (uncheck all others)
4. Click OK

Result: Excel keeps first person with each unique email, deletes duplicates.

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Scenario 2: Same Customer, Different Name Variations

Problem: Customer appears as “John Smith”, “J. Smith”, “Smith, John”

Excel limitation: These are treated as different people (no fuzzy matching)

Workarounds:

Option A: Standardize manually first

1. Create helper column
2. Formula: =UPPER(TRIM(A2)) to standardize
3. Remove duplicates on helper column
4. Delete helper column

Option B: Use AI-powered fuzzy matching (Mammoth)

• Automatically groups name variations
• “John Smith” = “J Smith” = “Smith, John”
• One-click consolidation

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Scenario 3: Transaction Log Deduplication

Problem: Same transaction imported twice from different sources

Key insight: Must match on multiple columns simultaneously

Solution:

1. Data → Remove Duplicates
2. Check: Transaction_ID, Date, Amount (all 3 columns)
3. Uncheck all other columns
4. Click OK

Excel only removes rows where ALL THREE values match.

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Scenario 4: Keep Most Recent Duplicate

Problem: Multiple records per customer—want to keep newest

Excel workaround:

1. Sort data by Date column (newest first)
2. Then run Remove Duplicates
3. Now “first occurrence” = newest record

Limitation: If you later add new data, you must re-sort before removing duplicates.

Automated solution: Business rules like “Keep MAX(Last_Updated)” applied automatically on data refresh.

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Scenario 5: Deduplicate Across 50 Excel Files

Problem: 50 regional files with overlapping records

Excel’s manual process:

1. Open first file → Copy data
2. Switch to master file → Paste
3. Repeat 50 times (hope Excel doesn’t crash)
4. Remove duplicates on master file
5. Manually split back by region

Time: 2-4 hours

Power Query process:

1. Data → From Folder → Select folder
2. Combine & Transform Data
3. Remove Duplicates
4. Close & Load

Time: 5-10 minutes

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FAQ: Remove Duplicates in Excel

What is the easiest way to remove duplicates in Excel?

The easiest method: Select your data → Data tab → Remove Duplicates button → Choose columns → Click OK. Excel deletes duplicates in seconds.

For large datasets (100K+ rows) or multiple files, use Power Query instead (Data → From Table/Range → Remove Duplicates).

What is the shortcut key for removing duplicates in Excel?

Excel’s keyboard shortcut: Alt + A + M

Press Alt, then A, then M in sequence (not simultaneously). This opens the Remove Duplicates dialog.

Note: Works in Excel 2016 and later.

How do I remove duplicates but keep one in Excel?

Excel’s Remove Duplicates automatically keeps one instance—the first occurrence.

To keep a different instance:

1. Sort your data first (by date, completeness, priority)
2. Then run Remove Duplicates
3. Excel keeps the first row, which is now your preferred record

Example: To keep newest records:

• Sort by Date (newest first)
• Remove Duplicates
• First (newest) instance stays

Does Remove Duplicates in Excel keep the first or last record?

Excel always keeps the first occurrence and deletes all subsequent duplicates. There’s no built-in option to keep the last.

Workaround: Sort data in reverse order before removing duplicates.

How to find duplicates in Excel without deleting them?

Method 1 – Conditional Formatting (easiest):

1. Select data range
2. Home → Conditional Formatting → Highlight Cells Rules → Duplicate Values
3. Duplicates highlighted in red (not deleted)

Method 2 – Formula:

1. Add helper column
2. Formula: =COUNTIF($A:$A,$A2)>1
3. Drag formula down
4. Filter or sort by TRUE values

Method 3 – Advanced Filter:

1. Data → Advanced
2. Select “Copy to another location”
3. Check “Unique records only”
4. Uniques copied elsewhere, originals unchanged

Can I remove duplicates based on one column but delete the entire row?

Yes! Excel’s Remove Duplicates deletes complete rows:

1. Select entire data range (all columns)
2. Data → Remove Duplicates
3. Uncheck all columns EXCEPT your key column (e.g., Email)
4. Click OK

Result: Excel checks only the Email column but deletes entire duplicate rows.

Why is Remove Duplicates slow in Excel?

Excel’s Remove Duplicates slows dramatically with:

Data size:

• 50K rows: Fast (5-10 seconds)
• 100K rows: Noticeable (30-60 seconds)
• 500K rows: Slow (3-5 minutes)
• 1M+ rows: Often crashes

Other factors:

• Many columns (20+): More data to compare
• Complex formulas in sheet: Excel recalculates after deletion
• Low RAM: Windows uses hard drive (very slow)

Solutions:

• Close other programs (free RAM)
• Copy to new sheet (remove formulas)
• Use 64-bit Excel (handles more memory)
• For 500K+ rows: Use Power Query or Mammoth

Can I undo Remove Duplicates in Excel?

Yes, immediately press Ctrl+Z (Undo) to restore deleted rows.

Critical warning: Undo only works if you haven’t saved the file. Once you save and close, deleted duplicates are gone permanently.

Best practice:

• Work on a copy of your file, OR
• Use Advanced Filter (copies unique records without deleting originals)

How do I remove duplicates from multiple columns simultaneously?

To check duplicates across multiple columns (e.g., First Name + Last Name + Email):

1. Select entire data range
2. Data → Remove Duplicates
3. Check all relevant columns: First_Name, Last_Name, Email
4. Click OK

How it works: Excel removes rows only if ALL checked columns match.

Example:

Row 1: John | Smith | john@email.com
Row 2: John | Smith | different@email.com

• Check Name columns only → Row 2 deleted (names match)
• Check Name + Email → Row 2 kept (email differs)

How do I remove duplicates in Excel for Mac?

Same steps as Windows Excel:

1. Select data range
2. Data tab → Remove Duplicates
3. Choose columns → Click OK

Keyboard shortcut: Command + Option + ; (semicolon)

Power Query also available in Excel for Mac 2016+.

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Key Takeaways

For small datasets (under 100K rows):

• ✅ Use Remove Duplicates button—fast and simple
• ✅ Use Conditional Formatting to review before deleting
• ✅ Use formulas for custom logic

For large or complex deduplication:

• ✅ Use Power Query for 100K+ rows
• ✅ Use Power Query for multiple files
• ✅ Use Power Query for repeatable workflows

When Excel struggles:

• ❌ 500K+ rows: Extremely slow or crashes
• ❌ Multiple files: Hours of manual work
• ❌ Fuzzy matching: Not possible
• ❌ Custom keep logic: Complex workarounds only

Real customer experience:

“We processed 200+ Excel files with duplicate customer records. Excel couldn’t handle the volume. Cloud-based deduplication reduced our 4-hour weekly process to 15 automated minutes.”

When to upgrade beyond Excel:

• You regularly work with 100K+ row datasets
• You need to deduplicate across multiple files weekly
• You want smart matching for name variations
• Your team wastes hours on manual deduplication
• You need audit trails and data quality reporting

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Next Steps

Master Excel Deduplication

For occasional, single-file needs:

1. Start with Method 1 (Remove Duplicates button) – fastest for simple cases
2. Use Method 3 (Conditional Formatting) when you need visual review before deleting
3. Learn Method 5 (Power Query) for larger datasets or multiple files

Stop Manual Deduplication Work

If you’re spending hours each week removing duplicates manually:

You need automated deduplication when:

• Deduplicating 10+ files weekly or monthly
• Working with 100K+ rows total across files
• Need fuzzy matching for name/company variations
• Require custom business rules (keep newest, most complete, etc.)
• Your team wastes 2+ hours weekly on this process

What Mammoth automates:

• Process 200+ Excel files simultaneously
• AI-powered fuzzy matching (“Microsoft Corp” = “MSFT”)
• Custom keep strategies (newest, most complete, highest value)
• Reusable pipelines – build once, run forever
• Schedule automatic deduplication (daily/weekly/monthly)
• Complete audit trails for compliance

Time savings: 4 hours weekly → 2.5 minutes (257 hours saved annually)

Get Started:
→ Start 7-day free trial (no credit card required)
→ Book a demo to see multi-file deduplication in action
→ View customer stories from teams who eliminated manual work

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Methods tested in Excel 2016, 2019, 2021, Excel 365, and Excel for Mac. Power Query available in Excel 2016 and later.