Add or Subtract Days
Add or subtract a number of days from any date to find the resulting date and weekday.
Add or subtract any number of days from a start date to find the resulting date and the day of the week it lands on. Use it to work out a deadline 90 days from now, a date 45 days before an event, or any offset in between — no calendar counting required.
Everything is calculated in your browser, and the result is shown in both a friendly format and ISO (YYYY-MM-DD).
Frequently asked questions
How do I add days to a date?
Pick a start date, enter the number of days, choose "add", and the tool returns the resulting date and weekday.
Can I subtract days too?
Yes — choose "subtract" to count backwards from your start date, useful for finding a deadline before an event.
Does it count weekends?
This tool counts calendar days including weekends. For working days only, use the business days calculator.
What date format does it output?
Both a readable format (with the weekday) and ISO 8601 (YYYY-MM-DD) for use in spreadsheets and code.