FREE SPREADSHEET COMPARE & VLOOKUP · 100% PRIVATE LOCAL PROCESSING
Compare Spreadsheets & Excel Files.
Up to 12 sources, one workspace.
Reconcile Excel and CSV files, look up values, and find missing records or duplicates. No complex formulas, no sign-up, and zero server uploads — your files stay on this device.
Excel + CSVDuckDB poweredFive-tab audit exportBring-your-own-AI SQL
01
Choose your sources
Source B
Or paste a column / table
Source C
Or paste a column / table
Source D
Or paste a column / table
Source E
Or paste a column / table
Source F
Or paste a column / table
Source G
Or paste a column / table
Source H
Or paste a column / table
Source I
Or paste a column / table
Source J
Or paste a column / table
Source K
Or paste a column / table
Source L
Or paste a column / table
Query up to 12 sources with SQL, or select any two to compare. Each pasted table or selected worksheet counts as one source. Select the same workbook again to use another worksheet. Limits: 250 MB and 2,000,000 rows per CSV/TSV/decoded table (25 MB and 500,000 rows for .xlsx; 100,000 rows for .xlsx exports), 1 GB combined workspace (including both versions during replacement), and 250 columns per source. Large datasets require a modern desktop browser with sufficient available RAM.
02
Choose your workflow
Query up to 12 sources with DuckDB SQL, or match columns between any two sources without formulas.
Load a spreadsheet in Step 01—or click —to unlock no-code column matching and the AI SQL context builder.
Choose two different loaded sources to match and compare. Add sources in Step 01, then select a pair above to look up values or export a five-tab reconciliation workbook.
Working with a single dataset? Switch to Query with SQL to query any loaded source immediately.
Tell us what to match
Choose matching columns and compare your files using the options below. No SQL required.
Pair columns, then select one or more matching keys. Keys stay as text. “Compare / add” selects fields to compare or bring over from the second source. Inferred types are suggestions; text is the default to preserve original values.
| Primary source / profile | Compare / look up against | Matching key | Compare / add | Approved type |
|---|
Lookup keeps all primary-source rows and adds selected columns from the second source under separate names. Approved cleaning and type conversions apply to mapped lookup output columns. Existing columns are never overwritten. Blank primary keys remain as unmatched rows.
Comparison exports keep original source values. Cleaning and conversions affect matching and comparison. Blank keys never match. Repeated keys and their counterparts go to Duplicates.
Copy the dataset context into your AI chat and describe what you need. Paste the SQL it writes below, then run it here. You can also write your own query.
1. Copy your dataset context
Nothing is sent automatically. Copied context and sample rows are only shared where you paste them.
2. Run the query locally
Click a table badge to insert at cursor. Read-only DuckDB SQL against raw VARCHAR values; sources stay intact.
SELECT / WITH · Read-only
03
Your results
Changed fields are highlighted in the workbook. CSV exports protect against formula execution; Excel exports contain values, not formulas. Original workbook formatting, macros, and live formulas are not preserved.
From spreadsheet guesswork to a clear audit trail.
Look up without formulas
Match on a customer ID, email, or multiple columns. Add data from another export without writing VLOOKUP.
See every difference
Separate unchanged, missing, changed, and ambiguous records. Compare by identity rather than row position.
Keep the evidence
Download Matched, Only in A, Only in B, Changed, and Duplicates in one Excel workbook.
How to compare spreadsheets and perform VLOOKUPs online
Reconcile datasets, identify mismatched records, and enrich columns without formula syntax. All processing runs privately inside your browser memory.
Upload your spreadsheets
Drop or browse files into Source A and Source B, then use Add source for up to 12 sources. Query all loaded sources with SQL or choose any pair for comparison. We support delimited text (.csv, .tsv, .txt) up to 250 MB and 2,000,000 rows per file, and Excel (.xlsx) up to 25 MB and 500,000 rows per worksheet. You can also paste copied table rows directly or select different worksheets from the same workbook. Your files never leave your computer.
Choose your comparison or lookup workflow
In Step 02, select Match & compare files to pair columns visually. Pick one or more matching key columns (such as Customer ID, SKU, or Email) and select which fields to compare or pull over from the selected second source. You can enable automatic whitespace trimming and case insensitivity, or set duplicate resolution policies when several matches occur.
Review and export the results
Click Run locally to inspect categorized counts and interactive tables grouped into Matched, Only in A, Only in B, Changed, and Duplicates. Download a multi-tab Excel workbook with modified fields highlighted, or save focused CSV extracts for reporting.
Common spreadsheet reconciliation use cases
Automated identity-based matching replaces manual row-by-row comparisons across finance, operations, sales, and data engineering workflows.
Month-end close & bank reconciliation
Match bank transactions against general ledger exports or payment provider settlements. Quickly flag unmatched disbursements, fee variances, and missing deposits with an organized audit trail.
Customer list deduplication & enrichment
Merge customer lists from Salesforce, HubSpot, or webinar exports. Look up missing attributes by email or account ID, isolate duplicate signups, and keep CRM contact records pristine.
Catalog & inventory audits
Compare supplier price sheets against active Shopify, Amazon, or ERP catalogs. Highlight discontinued SKUs, supplier price adjustments, and barcode changes before pushing live store updates.
Data migration & QA verification
Compare database exports before and after cloud migrations or ETL pipeline runs. Validate table row parity and detect truncated or shifted columns across legacy and target systems.
Why browser comparison beats complex Excel formulas
Formulas like VLOOKUP, XLOOKUP, and INDEX/MATCH work well for simple lookups, but large-scale reconciliations introduce common failure points that browser-based comparison solves:
Automatic whitespace & case normalization
Trailing spaces, leading tabs, and text-versus-number mismatches frequently trigger false #N/A errors in Excel. The tool trims and standardizes values so valid matches connect.
Explicit duplicate key detection
Standard lookup formulas stop at the first matching row, hiding duplicate records that distort totals. Ambiguous keys are isolated into a dedicated Duplicates tab so you can resolve them intentionally.
100% private local processing
Uploading financial records or customer lists to cloud utilities exposes sensitive PII and company data. All parsing and reconciliation here executes locally in your browser with zero server uploads.
Instant five-tab reconciliation workbook
Skip setting up complex conditional formatting rules across separate sheets. Export a five-sheet workbook separating matched rows, items only in A, items only in B, changed fields, and duplicates.
Frequently asked questions
Are my spreadsheets or CSV files uploaded to any server or cloud database?
No. All file reading, data normalization, row comparisons, and Excel workbook exports run entirely inside your browser's local memory using Web Workers and DuckDB WebAssembly. Your files never touch an external server.
How is this tool different from Excel's VLOOKUP, XLOOKUP, or INDEX/MATCH?
Excel formulas break easily on trailing whitespace, case differences, and mismatched data types, and can cause Excel to freeze on large files. This tool pairs columns visually without formulas, automatically normalizes data types, isolates duplicate keys, and exports a 5-tab audit trail.
What file formats and file sizes are supported?
You can compare comma-separated values (.csv), tab-separated values (.tsv), and plain text tables (.txt) up to 250 MB and 2,000,000 rows per file, or Excel workbooks (.xlsx) up to 25 MB and 500,000 rows per worksheet, with up to 250 columns per source. Load up to 12 sources within a 1 GB combined workspace limit, counting file / decoded table sizes and both versions during replacement. Large files require a modern desktop system with sufficient available RAM.
What is included in the five-tab reconciliation workbook?
The exported Excel workbook contains five distinct sheets: 1) Matched (identical records), 2) Only in A (records present in Source A but absent from B), 3) Only in B (records present in Source B but absent from A), 4) Changed (records matching on key but differing in values, with changed cells highlighted), and 5) Duplicates (records with repeated keys requiring resolution). Source letters in worksheet names and columns follow your selected pair.
How does the in-browser SQL querying with DuckDB work?
The tool embeds DuckDB compiled to WebAssembly inside your browser. You can execute read-only standard SQL queries directly against up to 12 loaded tables, "A" through "L", or copy pre-formatted schema context into ChatGPT or Claude to generate queries for you.
Can I compare two different worksheets within the same Excel workbook?
Yes. Simply load the same Excel (.xlsx) file into both Source A and Source B, then select a different worksheet from the dropdown menu on each source card.
How are duplicate keys and blank cells handled during comparison?
Blank keys never match and are flagged for review. For duplicate keys in the selected second source during lookups, you can choose to halt and resolve, use the first matching row, use the last matching row, or return all matches. In comparison mode, all repeated keys and their counterparts are isolated into the Duplicates sheet.
Documenting spreadsheet workflows or sharing audit walkthroughs?
Record your screen, voice, and camera with ScreencastKit Recorder. Share instant browser playback links with automatic pause removal and zero upload wait times.