Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Home / Text & Data / Date Calculator

Date Calculator

Difference between dates, add/subtract days, business days.

Free, no uploads, no sign-up. Runs 100% in your browser.

How Date Calculator works

Date Calculator runs entirely in your browser. Difference between dates, add/subtract days, business days. Under the hood it uses Plain TypeScript (small, dependency-free code that runs instantly in your tab). Your files are read into this tab’s memory, processed on your own CPU, and handed back to you as a download. Nothing is sent to a server.

How to use Date Calculator

Open Date Calculator and paste your text.
Choose an operation or option.
Review the live result.
Copy it or download it.

Tips

Text never leaves your device, so it is safe for drafts and private notes.

Date Calculator FAQ

Are my files uploaded?: No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
Is it free? Are there limits or watermarks?: Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
Does it work offline?: Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

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