The Date & Age Calculator answers the most common date questions in one place. In Difference mode it computes the exact span between two dates in years, months and days, plus the total number of days and the weekday of each date — perfect for working out an age, an anniversary or a deadline. In Add / Subtract mode it shifts a date forward or back by a number of days, weeks, months or years and tells you the resulting date and its day of the week. Everything is calculated locally in your browser.
How to Use the Calculator
- Pick Difference to compare two dates, or Add / Subtract to shift a date.
- Enter the dates (or the amount and unit to add or subtract).
- Read the result — the exact span and weekdays, or the new date.
Benefits and Use Cases
- Calculate ages, anniversaries, due dates and project deadlines precisely.
- Find what date falls a number of days, weeks or months from another.
- Runs entirely in your browser using the built-in calendar — nothing is uploaded.