Date Calculator — Days Between Dates & Add Days
A date calculator finds how much time sits between two dates — in years, months and days, plus the total days — or adds and subtracts days from any date.
How it works
- To find a gap, enter a start date and an end date.
- To shift a date, enter a date and how many days to add or subtract.
- The answer appears instantly, with the total number of days as well.
Formula
Worked example
From 1 January 2026 to 6 November 2026 is 309 days — 10 months and 5 days. And adding 45 days to 6 November 2026 gives 21 December 2026.
Frequently asked questions
How many days are between two dates?
Enter both dates above and the calculator shows the total days, as well as the gap in years, months and days.
How do I add days to a date?
Enter the starting date and how many days to add. For example, 45 days after 6 November 2026 is 21 December 2026.
How do I count months between dates?
The calculator counts full calendar months first, then the remaining days — so 1 January to 1 March is 2 months, not 59 or 60 days.
Does the date calculator handle leap years?
Yes. It uses real calendar dates, so leap days like 29 February 2028 are counted correctly.
What date is 100 days from today?
Enter today's date and add 100 days above. The calculator gives the exact date, including the day of the week.
How do I find my age in days?
Enter your date of birth as the start date and today as the end date. The total days shown is how many days you have lived — or use the Age Calculator for years, months and days as well.