Date & Age
Date Calculator
Days between two dates, or a date shifted by N days.
🔒 Runs entirely in your browser — nothing here is ever uploaded
CalcoTools · Date Calculator · generated 8/23/2026, 1:07:25 PM
About the Date Calculator
Calculates the number of days, weeks, or years between two dates, or projects a new date by adding or subtracting a number of days from a starting date.
How to use it
- For a gap between dates: enter the From and To dates in the first section.
- For a shifted date: enter a Base date and a number of Days (+/-) in the second section.
- Read the result in each section's readout.
Formula
Difference = (Date2 − Date1) in days, converted to weeks or years as needed
Projected date = Base date ± N days
Worked example
From January 1 to August 9 is 220 days — about 31.4 weeks, or roughly 0.6 years.
Recommendations
- • For age specifically, from a birthdate to today, the Age Calculator gives a more natural years/months/days breakdown than a raw day count.
- • Negative values in 'add days' mode subtract instead — useful for finding a date some number of days in the past.
- • Calendar month lengths aren't uniform, so the 'years' figure shown is a decimal approximation based on average year length, not a calendar year count.
Frequently asked questions
Yes — it works with actual calendar dates via your browser's date engine, which already handles leap years correctly.