Date Calculator
Count days between dates or add and subtract calendar days, with clear endpoint and leap-year handling.
Count calendar days between dates using Gregorian dates, independently of time zones and daylight saving.
Result
Negative values indicate the end date is before the start. Inclusive counting gives one day when both dates are the same. This counts calendar dates, not elapsed hours or business days.
How to use this calculator
Count calendar days between dates using Gregorian dates, independently of time zones and daylight saving. Enter amounts in the units shown, select the applicable options, and click Calculate. Use Reset to restore the starting values.
Calculation formula
Exclusive difference = end calendar day − start calendar day. Including both endpoints adds one day to the magnitude.
Assumptions and accuracy
Check the selected mode, units, date endpoints and result notes. Currency selection controls display and rounding, not exchange rates. Calendar calculations do not include holidays or local time-of-day.
Choose what to calculate
Days between two dates calculator
Count calendar days between dates or add and subtract days. Calendar arithmetic handles leap years and does not depend on daylight-saving hour changes.
Open this calculationUnderstanding this calculation
Count days between two calendar dates or find the date a signed number of days away. Endpoint inclusion and chronological direction are explicit, so deadline calculations do not depend on the computer’s local time zone.
Worked examples
Count across a leap day
Use the explicitly stated inputs; the example link fills them in.
- February 28 to February 29 is one day.
- February 29 to March 1 is a second day.
There are two calendar days between the dates.
Try these inputsAdd one day at the end of February in a leap year
Use the explicitly stated inputs; the example link fills them in.
- One calendar day after February 28, 2024 is February 29, 2024.
The resulting date is 2024-02-29.
Try these inputsCommon questions
Are both endpoint dates included?
Only when you select inclusive counting. Otherwise the result is the signed difference between the dates, giving zero for equal dates.
Does the calculation account for leap years?
Yes. Calendar arithmetic includes February 29 when valid; invalid dates and results outside the supported year range are rejected.
Scope and assumptions
Gregorian calendar dates in years 0001–9999 only. This is not an elapsed-hours, business-day or holiday calculator. Inclusive counting adds one day to the magnitude and gives one for equal dates.
Sources
Calculation notes checked . Examples are mathematical checks under the stated assumptions.
Calculation methods and formulas
Days Between Dates
Count calendar days between dates using Gregorian dates, independently of time zones and daylight saving.
Exclusive difference = end calendar day − start calendar day. Including both endpoints adds one day to the magnitude.
Add or Subtract Days
Add or subtract a whole number of calendar days.
Resulting calendar day = starting calendar day + signed number of days.
See our calculation methodology and review status for data versions, rounding and validation limitations.