Date Calculator
Count the days between two dates, or add and subtract days, weeks, months, and years from any date.
Days between two dates
Add or subtract from a date
How date math works
The days-between count is the number of full days from the start date to the end date. Business days exclude Saturdays and Sundays (but not public holidays, which vary by country). When adding months or years, the calculator keeps the same day-of-month where possible, adjusting for shorter months (e.g., January 31 + 1 month lands on the last day of February).
From Jan 1 to Dec 31, 2026 is 364 days (about 260 business days). Adding 90 days to July 22 gives October 20.
Everyday date questions
Handy for project deadlines, contract and notice periods, warranty windows, vacation planning, and "how many days until…" countdowns. For business-day-sensitive deadlines, remember this tool skips weekends but not holidays — check a holiday calendar for the exact working days. For someone's age specifically, the age calculator breaks it into years, months, and days; for durations in hours and minutes, use the time calculator.
Frequently asked questions
How do I count the days between two dates?
Subtract the earlier from the later. This tool also shows business days (weekends excluded).
How do I add days to a date?
Use add/subtract mode with days, weeks, months, or years.
Are business days different from calendar days?
Yes — business days count Mon–Fri only (holidays not excluded here).
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Last reviewed: July 2026.