Date Calculator
Days between dates, or add time to a date.
Runs in your browserRelated
About
Date Calculator answers two related questions: how many days, weeks, months, or years sit between two dates, and what date you land on after adding or subtracting a span of time from a starting date. It accounts for real calendar irregularities — varying month lengths and leap years — rather than assuming flat 30-day months. Runs fully offline; no date you enter is transmitted anywhere.
Frequently asked
- Does it account for leap years correctly?
- Yes — the day/month/year difference is computed against the actual calendar, including leap years, not a fixed 365-day approximation.
- Can I subtract time instead of adding it?
- Yes, the add/subtract mode accepts either direction, so you can work backward from a date just as easily as forward.