Time Tool

Date Duration Calculator

Choose a start date and end date to calculate the duration in days, weeks plus days, and total hours. Turn inclusive counting on when both boundary dates should count.

Date range inputs

Date duration formula

Date duration = end date - start date; inclusive duration adds one day when both boundary dates should count.

Inclusive option

Switch between elapsed-day counting and inclusive date range counting.

Weeks plus days

Convert long date spans into a more readable planning format.

Browser time zone

Date inputs are evaluated in your local browser time zone.

How to calculate the duration between dates

Date duration can be counted in two common ways. Exclusive counting measures the elapsed time from the start date to the end date. Inclusive counting counts both the start date and the end date, which is useful for bookings, event ranges, study plans, and deadlines where both dates are active.

Use the plain day count for schedules, the weeks-plus-days result for planning blocks, and total hours when you need a rough conversion for timelines. For precise time-of-day calculations, use a countdown or time difference tool that includes hours and minutes.

Date duration inputs

InputWhat it meansPlanning note
Start dateThe first date in the rangeUse the first active day for inclusive ranges.
End dateThe final date in the rangeCan be before or after the start date.
Inclusive countingWhether to count both boundary datesTurn on for bookings, event spans, and date ranges shown as inclusive.
Total hoursDays multiplied by 24Useful as a quick planning conversion, not a time-of-day calculation.

Common use cases

Trip planning

Count the length of a vacation or hotel stay.

Project timelines

Measure calendar days between kickoff and deadline.

Study plans

Break a schedule into weeks and remaining days.

Frequently asked questions

How do I calculate days between two dates?

Subtract the start date from the end date. This calculator does that in your browser and also shows weeks plus days.

What does inclusive counting mean?

Inclusive counting counts both the start date and end date, adding one day to the elapsed range.

Can the end date be before the start date?

Yes. The calculator reports the absolute duration and notes whether the end date is before or after the start date.

Does this include time of day?

No. This page uses whole dates. Use the countdown calculator for date and time countdowns.

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Last reviewed: August 1, 2026. Date calculations use your browser time zone unless noted.

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