Date Calculator
Add a number of days to a start date, or compare two dates to see the day difference.
How it works
- 1
Enter your values in the fields.
- 2
Results update automatically as you type.
- 3
Use Reset to clear and try another scenario.
Why use this calculator
- Add/subtract days
- Days between dates
- ISO date inputs
- Handy for deadlines
Planning with dates
Use this tool for project deadlines, travel buffers, or counting days between events.
Difference field
If you provide an end date, days between start and end are shown as well.
Frequently asked questions
Can I subtract days?
Yes — enter a negative number of days.
Inclusive counting?
Difference is whole days between calendar dates.
Time of day?
Not included — date-only math.