CCalcanova
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Converters & Dates

Date Add & Subtract Calculator

Add or subtract days, weeks, months, and years from any date — with an option to count only working days.

Defaults to today

Resulting date
Wednesday, August 26, 2026
Days after the start date
30 days
ISO date (YYYY-MM-DD)
2026-08-26

Years and months are applied first, then weeks and days. If the day of the month doesn't exist in the target month, it rolls into the next one — 31 January plus one month gives 3 March in a 28-day February.

Add or subtract time from any date

Pick a start date, choose whether to move forward or backward, and enter any mix of years, months, weeks, and days. The calculator returns the exact resulting date with its weekday, plus the total number of calendar days between the two — useful whenever a contract, deadline, or reminder is written as "90 days from signing" rather than as a fixed date.

Worked example

90 days after 25 July 2026 is Friday 23 October 2026. Switch to working days and 10 working days after Monday 27 July 2026 is Monday 10 August 2026 — four calendar days longer, because two weekends fall inside the window. That gap is exactly why payment terms and notice periods should always state whether they mean calendar or business days.

Common uses

Invoice due dates on net-30 or net-60 terms, statutory notice and cooling-off periods, visa and permit validity windows, warranty and return deadlines, court and filing deadlines counted in business days, project milestones planned backwards from a launch, and medication or appointment schedules counted in weeks.

Frequently asked questions

+What happens when the target month is too short?

Years and months are applied first, then weeks and days. If the day of the month doesn't exist in the month you land in, it rolls forward: 31 January plus one month gives 3 March in a 28-day February. If you need the last day of the month instead, add the months first and then adjust the day yourself.

+Which days count as working days?

Monday through Friday. Public holidays aren't excluded because they differ by country, region, and year. If your deadline runs through a holiday period, count the holidays that fall inside the window and add them to the number of working days.

+Does the start date itself count?

No — counting starts the day after. Adding 1 day to Monday gives Tuesday, and 1 working day after Friday is the following Monday. That matches how notice periods and "within X days" clauses are normally read.

+Are leap years handled?

Yes. All arithmetic runs on the real calendar, so 29 February in leap years is counted automatically and adding one year to 29 February 2028 lands on 1 March 2029.

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