Date Difference Calculator
Compare two dates or add a number of days to a start date. Calculations run locally.
Result: —
How it works
- Difference uses UTC midnight for each calendar date to avoid timezone skew.
- Weeks = whole days ÷ 7; months are approximate (days ÷ 30.4375).
- Add N days shifts the start date forward (or backward if N is negative).
Examples
- 2026-03-01 → 2026-03-31 = 30 days
- 2026-01-01 → 2026-01-15 = 14 days · 2 weeks
- 2026-10-31 + 30 days → 2026-11-30
- 2024-02-28 → 2024-03-01 = 2 days (leap year includes Feb 29)
Countdowns and business days
For “how many days until…” and rough business-day estimates, readhow many days until a date. This tool reports calendar day difference; subtract weekends/holidays yourself when you need working days only. For exact years/months/days from a birthday, use theAge Calculator.
FAQ
Is the end date included?
The difference is end − start in whole days (same calendar day = 0). Inclusive trip counting may add 1.
How accurate are months?
Months are approximate using the average Gregorian month length (30.4375 days). Prefer days for exact spans.
Does this handle leap years?
Yes. Day counts come from real calendar dates, so Feb 29 in leap years is included automatically.
Can I count business days only?
This calculator returns calendar days. For a rough estimate, multiply long spans by 5/7, or walk day-by-day skipping weekends. See the countdown guide for examples.
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