Free in your browser. $49 once for the desktop app.
Compare two CSV files here for free, with no account. Calamo Pro opens Excel workbooks and files of several GB, and you try all of it for 14 days before you pay.
Calamo Pro
$49 once, no subscription
For one person, on up to 3 computers. Windows, Linux and macOS (beta).
- Compare Excel, CSV and Parquet files by key, also several GB each
- Browse and edit one file: filters, column profile, pivot table, find and replace
- A copy of the new file with every change marked, and a report for sign-off
Download free trial Buy for $49
- 14 days free, no account or card
- 30-day refund, no reason needed
- Every 1.x update included
The price includes VAT in the EU, the UK and most other countries. In the US, Canada and India, sales tax is added where it applies. Checkout shows the total before you pay.
Free
$0
In your browser, no account. Files are never uploaded.
- Compare two CSV or TSV files by a key column
- Every added, removed and changed row, cell by cell
- Download the full report as CSV
Free and Pro side by side
| Feature | Free | Pro |
|---|---|---|
| Yes | Yes | |
| Files never leave your computer | Yes | Yes |
| File size | A few hundred MB | Several GB (4.3 GB measured) |
| CSV and TSV | Yes | Yes |
| Excel workbooks (XLSX) | Save as CSV first | Yes |
| – | Yes | |
 | ||
| – | Yes | |
| – | Yes | |
 | ||
| – | Yes | |
 | ||
| – | Yes | |
Same engine as the app; the exit code tells a script whether anything changed. | ||
| Price | $0 | $49 once |
Click a row to see it in the app. Sizes measured on one desktop, November 2026: speeds on the Pro page.
What happens when you buy
- Pay at Polar. Polar, our reseller, takes the card payment and sends the receipt.
- Get the key by email. It arrives a minute later, from Polar.
- Enter it in the app. Help → Licence. After that the app works offline; it checks the key about once a month when you are online.
Questions about Pro
Can I try Pro first?
Yes, for 14 days, with no account and no card. Download it for Windows, Linux or macOS.
What does “once” mean?
You pay one time for a licence for one person. There is no subscription and nothing renews.
Which updates are included?
Every 1.x version, for at least two years from your purchase. Licence terms
Can I move it to another computer?
Yes. It runs on up to 3 computers at a time. To move it, remove the key in Help → Licence and enter it on the new computer.
What if it doesn’t work for me?
Within 30 days of buying you get a full refund, no reason needed. Refund terms
Can my company pay, or buy several licences?
Yes. Each licence is for one person; buy one per person. For an invoice with your company details or several licences at once, write to hello@calamo.io.
Will the free tool stay free?
Yes. The browser tool needs no account and stays free. Only the desktop and command-line version is paid.
Calamo is made by one person: me, Michal Piják, a data engineer in Bratislava. If something is wrong or missing, write to hello@calamo.io and I answer myself.