Date Teller

Dates calculated on your device. Nothing leaves it.

Business days PRO

Start date

End date

Include end day

Date

Amount (0-9999)

Unit

Operation

Date

Custom format PRO

One per line: a date, or "date + N unit" (d, w, m, y)

Result

History PRO

Pro saves your last 50 calculations on this device.

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🔒 100% private · runs in your browser

Date math, done in your browser

Find the gap between two dates, add or subtract time, and format the result, all offline.

Difference: years, months, days, plus total days, weeks, hours between two dates
Add/Subtract: add or subtract up to 9,999 days, weeks, months or years from a date
Format: show a result in 4 formats (ISO 2024-03-09, US 03/09/2024, EU 09/03/2024, long 'March 9, 2024') with weekday
Copy button on every result
Today shortcut and swap-dates button

Business-days mode: skip weekends (and optional custom holiday list) in difference and add/subtract
Batch: paste up to 500 lines of dates or 'date + N unit' and calculate all at once
Export batch results as CSV, JSON or PDF
All 12 custom format tokens (YYYY, MM, DD, ddd, MMMM, etc.)
History of last 50 calculations saved in localStorage

100% private — your data never leaves your device. v1.0.0