Date Calculator
Use one mode to compare two dates and another to move a starting date by a day count. Distinguishing those operations avoids confusing a duration with the resulting calendar date.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Loading the tool. If it does not appear, reload this page.
How to use this tool
For a difference, supply start and end dates. For date shifting, supply a start and a signed day count; handle any inclusive counting convention separately from the arithmetic.
Results and examples
The difference between 2026-01-01 and 2026-01-08 is seven days. Adding 7 to January 1 in the other mode reaches January 8, illustrating the relationship between the operations.
Limitations
- No legal deadline or public-holiday adjustment is applied.
- The implementation follows device-local calendar dates and JavaScript date normalization.
Fields
| Field | Guidance and constraints |
|---|---|
| Between two dates | Check the unit and format displayed beside this field. |
| Add days to a date | Check the unit and format displayed beside this field. |
| Start date | Check the unit and format displayed beside this field. |
| End date | Check the unit and format displayed beside this field. |
| Days to add (negative to subtract) | Check the unit and format displayed beside this field. |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
How are the two calculation modes related?
The difference between 2026-01-01 and 2026-01-08 is seven days. Adding 7 to January 1 in the other mode reaches January 8, illustrating the relationship between the operations.
Can this replace a legal deadline calculation?
No legal deadline or public-holiday adjustment is applied. The implementation follows device-local calendar dates and JavaScript date normalization.
