Time Window Calculator

Calculate practical time windows for deadlines, delivery planning, working-day estimates and date ranges. Count time between two dates, add or subtract calendar or business days, skip custom holidays, and check weekdays or ISO week numbers.

Calculation modeStart date and timeEnd date and timeInclude end date in day count

Time window

Start: May 05, 2026, 08:41 AM
End: May 19, 2026, 08:41 AM
Calendar span: 0 years, 0 months, 14 days, 0 hours, 0 minutes
Total days: 14.0000
Date count: 14 days
Business days: 10
Total hours: 336.00
Total minutes: 20160

All calculations run locally in your browser. Dates and time windows are not uploaded, logged or stored.

How to use this tool

Enter the required values in the labeled fields. Results update in your browser and are announced for assistive technologies. Use realistic measurements and verify important outcomes before acting on them.

Formula or logic

The calculator uses browser Date values locally. Calendar spans are computed as years, months, days, hours and minutes. Business-day mode counts weekdays and skips user-entered holiday dates. No external calendar or API is called.

Example calculation

Example: Count from Monday 09:00 to Friday 17:00, include or exclude the end date, then compare calendar days with business days.

Frequently asked questions

Does this send dates to a server?

No. Date and time calculations run fully in your browser.

Can it skip weekends and holidays?

Yes. Business-day mode skips Saturdays and Sundays, and you can add custom holiday dates in YYYY-MM-DD format.

Can I add or subtract days from a date?

Yes. Use plus/minus mode to add or subtract calendar days or business days.

Is this the same as a legal deadline calculator?

No. It is a planning tool. Legal, tax, customs and contractual deadlines should be verified independently.

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