Date Calculator (Add & Subtract)
Add or subtract days, weeks, months and years from a date, with an optional business-days mode.
Enter your values to see the result.
Continue your work
- Date Difference Calculator — Count the days between two dates.
- Age Calculator — Calculate an exact age from a birth date.
Rate this tool
0.0
0 ratings
- 5 stars 0
- 4 stars 0
- 3 stars 0
- 2 stars 0
- 1 star 0
Share this tool
Found it useful? Send it to a friend or teammate.
Report an issue
Something broken or not quite right? Tell us and we will look into it.
Clear instructions
Find steps, examples and limitations below.
Use online
Open the tool in a supported web browser.
Free to use
No sign-up required. Tool-specific limits may apply.
How to use the Date Calculator (Add & Subtract)
The date calculator finds the date a number of days, weeks, months or years before or after another date. It handles month lengths and leap years correctly, can count business days only (skipping weekends) for deadlines and delivery times, and shows the weekday, ISO week number and day of the year for the result.
- 1 Choose the start date and whether to add or subtract.
- 2 Enter the years, months, weeks and days to add or subtract.
- 3 Tick business days to skip Saturdays and Sundays, then read the result date.
Example and practical tips
Adding 90 days to September 26, 2026 gives Friday, December 25, 2026. Adding 10 business days to a Monday lands on the Monday two weeks later.
Frequently asked questions
How are months added to dates like January 31?
If the target month is shorter, the date moves to its last day: January 31 + 1 month = February 28, or February 29 in a leap year.
Does it include public holidays?
Business-day mode skips weekends only. Public holidays vary by country, so subtract them yourself for exact deadlines.
What is the ISO week number?
The ISO standard numbers weeks from Monday to Sunday, with week 1 being the week that contains the first Thursday of the year.