DateDelta

Add or Subtract Days Calculator

Skip the calendar counting — enter a start date and a day count, get the exact resulting date.

Handles month and year rollovers automatically

Adding days across a month boundary (like 20 days from January 25th) or even a year boundary (December into January) requires correctly accounting for varying month lengths and leap years — this calculator handles all of that for you.

Common uses

Useful for calculating due dates, contract deadlines, return windows, or any 'X days from now' or 'X days before' question that's tedious to count by hand on a calendar.

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DateDelta

Add or Subtract Days Calculator

Skip the calendar counting — enter a start date and a day count, get the exact resulting date.

Start date

Days to add (negative to subtract)

Resulting date

2026-08-21

What you entered

Start date: 2026-07-22Days: +30

1
Add days to the start date
2026-07-22 + 30 days= 2026-08-21

Result

Resulting date: 2026-08-21

Adding 30 days to 2026-07-22 lands on 2026-08-21.

Handles month and year rollovers automatically

Common uses

Useful for calculating due dates, contract deadlines, return windows, or any 'X days from now' or 'X days before' question that's tedious to count by hand on a calendar.