Date Calculator
Date Calculator is a free online tool for date math. It calculates the number of days between two dates — also expressed in years, months, and weeks — and can add or subtract days from a base date to find a past or future date. Quick presets like today, tomorrow, yesterday, and 7 days ago fill dates in one click.
All calculations run locally in your browser and nothing is collected; no sign-up is needed. Handy for measuring project timelines, counting down to exams or anniversaries, working out contract deadlines, or checking visa stay durations.
How to Use
- Pick a mode: date difference or add/subtract days
- For a difference, choose the start and end dates
- For add/subtract, choose a base date, enter the number of days, and pick forward or backward
- Click Calculate to see the result in days, plus years, months, and weeks
FAQ
Is the date calculator free?
Yes, it is completely free with no sign-up and unlimited use.
Are the dates I enter sent anywhere?
No. Everything is calculated locally in your browser; your input never reaches a server.
Does the day count include the start date?
It computes the difference between the two dates, so January 1 to January 2 is 1 day. If your use case counts both endpoints (like hotel nights vs. days off), simply add 1 to the result.
How are years and months converted?
Conversions use averages — 30.44 days per month and 365.25 days per year (accounting for leap years) — so they are close approximations. Rely on the day count when you need exact numbers.