Date Calculator
Add or subtract years, months, weeks, days, and business days from any date — or find the difference between two dates.
Result
Tue, Nov 17, 2026
2026-11-17
How to use
- Pick a mode: Add / Subtract or Between.
- Set the date(s) and any offsets you want.
- Read the resulting date or the breakdown between the two dates.
About this tool
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Add or subtract years, months, weeks and days from a date and get the result with its weekday, which is usually the part you actually wanted to know. A separate business-days field steps forward or backward skipping Saturdays and Sundays, the arithmetic behind a five-working-day turnaround or a notice period counted in working days. One thing it cannot know is your public holidays: they differ by country and by region, and some move every year, so a deadline that lands near one still needs checking against the right calendar. Handy for contract dates, delivery estimates, notice periods, warranty expiry and any question that starts with what date is ninety days from now.
Frequently asked questions
What counts as a business day?
Monday through Friday. Public holidays aren't subtracted — they vary by country. For an exact deadline in your jurisdiction, double-check against the local holiday calendar.
How are months handled?
By calendar month. Adding 1 month to Jan 31 gives Feb 28 (Feb 29 in a leap year): when the target month is shorter, the day is clamped to its last day rather than overflowing into the next month. This matches how most spreadsheets and SQL databases do month arithmetic.
Why does 'years 0 months 11 days 30' show instead of '1 year'?
The Between view always uses calendar components — full calendar years first, then remaining months, then remaining days. 11 months + 30 days is not a full year because the next month might be 31 days.
Is the date stored?
Only in your browser's local storage so the inputs survive a reload. Nothing is uploaded.
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