Pricing

Merge messy spreadsheets that are too big for Excel — in plain English.

Drop two files, describe the merge in plain English, and download clean data. No formulas, no VLOOKUP, no Excel crashes.

Drag & drop 2 spreadsheets here, or click to browse

Processed locally in your browser • Your files never leave your computer • Up to 300MB per merge

Free to try — no sign-up to run your first merge. Your data stays on your machine.

Data merging without the spreadsheet headaches

Too Big for Excel? No Problem.

Excel chokes and freezes past a million rows. TenMil handles huge files right in your browser — no plugins, no waiting, no crashing.

Ditch the Syntax.

Stop Googling INDEX/MATCH or debugging #N/A errors. Just describe what you want, and our AI intelligently maps your column headers so you get a flawless merge without writing a single formula.

Built for Operators.

Perfect for enriching data sets like marketing outreach lists, mapping e-commerce customer data, combining Shopify sales exports, or matching payment logs.

Why TenMil Beats Excel VLOOKUP

CapabilityExcel VLOOKUPTenMil.ai
Logic TypeManual Formula (Cell-based)Natural Language (Intent-based)
Data ScopeOne-directional lookup onlyLEFT, INNER & FULL OUTER joins
Setup TimeWrite & debug formulasAuto-detected join key in seconds
AccuracyManual & error-proneDeterministic engine — same result every run
StabilityFormulas break on column moveAI-suggested keys & join type
Unmatched Rows#N/A errors scattered in cellsHighlighted & counted per bucket
Input SourcesLocal files onlyLocal files + Google Drive
ExportManual copy-pasteExcel, CSV, or Google Drive (one click)
ProcessingLocal (single-threaded)In-browser SQL engine, no upload required
PrivacyLocal FilePrivate (Zero Cloud Storage)*

*Files are processed entirely in your browser and are never uploaded or stored on our servers.

Built for absolute trust and reliability.

Zero-Data-Retention Security

Your data never leaves this browser tab.

To figure out how your files match up, we analyze your column structure and send only a small, anonymized statistical sample to our AI — never your full dataset. That sample is encrypted in transit, never used to train models, and discarded immediately. Your full data is never uploaded, never stored on a server, and is gone the moment you close the tab.

100% Deterministic Math

Zero hallucinations, every time.

Standard AI struggles with exact math and data privacy. TenMil solves this by separating the intelligence from the execution. Our schema-aware AI parses your plain-English commands and generates the underlying data logic, completely insulated from your raw files. Our local SQL engine then executes that logic with absolute, deterministic precision.

Frequently Asked Questions

What exactly does TenMil.ai do?
TenMil.ai merges two large & messy spreadsheets into one unified file directly in your browser. Instead of writing complex formulas or dealing with Excel freezing, you just describe what you want in plain English (e.g., "Merge these by customer email, keep all rows from the left file"). Our AI handles the layout planning, while a high-performance database engine executes the merge locally. All in seconds.
Is my data uploaded to your servers? Is it secure?
Your full row-level dataset never leaves your computer. TenMil uses advanced in-browser processing (DuckDB-WASM) to run the actual merge locally. To plan your merge from your plain-English prompt, we send only a small, anonymized sample of your column headers to our AI — never your actual row data. This structure sample is encrypted in transit, never used for AI training, and discarded immediately. We run no servers that store, read, or log your files.
Is there a file size or row limit?
The combined upload size is capped at 300 MB across two files — which is more than large enough to handle massive datasets that routinely crash Excel. For enterprise-grade workloads exceeding 10M+ rows, you can join the waitlist for our upcoming Enterprise Engine.
Do I need to know SQL, Python, or how to code?
Not at all. Just upload your two files and type what you want to achieve. TenMil's AI automatically detects your column layouts, selects the ideal join keys, and identifies the correct match type (LEFT, INNER, FULL OUTER, or stack/union). You simply review and let our deterministic SQL engine handle the heavy lifting under the hood.
Can I merge a CSV file with an Excel (.xlsx) file?
Yes. You can seamlessly merge a CSV with an XLSX file, two CSVs, or two XLSX files. TenMil normalizes the data formats automatically and allows you to download your unified result as a clean file.
How is this better than using VLOOKUP or INDEX-MATCH in Excel?
Excel slows to a painful crawl or crashes entirely once you hit tens of thousands of rows. TenMil runs on DuckDB, an elite analytical database engine built for scale. Merges that take Excel minutes — or kill your spreadsheet program entirely — finish here in seconds. Best of all, because it runs on strict database logic, the results are completely deterministic and perfectly accurate every time.
Do I need to download or install any software?
No installation, no browser extensions, and no corporate IT approval required. TenMil runs entirely within any modern web browser using your machine's native local resources.
Are my original files altered or changed?
Never. TenMil strictly reads your original files to perform the merge logic inside your browser tab. Your original source files remain completely untouched and safe on your hard drive.
Do I need to create an account to use TenMil?
No account is required to upload files, run merges, or preview your data. To download your final merged file, we only ask for your email. Free accounts include 3 free downloads per day, which reset automatically at midnight UTC.
Is TenMil really free?
Yes, our core merge engine is free to use and includes 3 file downloads per day. For power users who need unlimited daily downloads, we offer a Pro plan at $10/month or $100/year that you can cancel at any time.