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Date Calculator

The days, weeks, months and business days between two dates, and a date plus or minus a number of days, weeks, months, years or business days, with its ISO week number.

About this tool What it's for, how to use it and an example

What it's for

Count the time between two dates, or find the date a number of days, weeks, months, years or working days from another. Each result also shows the day of the week and the ISO week number.

For example, when you need to know how many working days are left before a deadline, or the date 30 days after an invoice was issued.

How to use it

Between two dates: pick a start and an end date. You get the total in days, in weeks and days, in months and days, and the number of business days.

Add or subtract: pick a date, enter an amount (negative to go backwards) and choose a unit: days, weeks, months, years or business days (Monday to Friday).

Example

Under Add or subtract, pick 1 October 2026, enter 10 and choose Business days. The result is:

Thursday, 15 October 2026 (2026-10-15, week 42 of 2026)

With Days instead, it’s Sunday, 11 October 2026.

Good to know

Business days skip weekends but not public holidays, so adjust for bank holidays yourself. Business-day counts include the end date but not the start date.

Between two dates

Add or subtract

Business days skip weekends, not public holidays.

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Private: this tool runs in your browser. Nothing you type, paste or choose leaves this page.

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