Days Between Dates Calculator
Counts days between two dates.
Result
- Days between
- 364 days
- Weeks
- 52.00 weeks
- Including end date
- 365 days
How to use the days between dates calculator
- Enter the start date.
- Enter the end date.
- The results update as you type, or press Calculate.
- Read the days between first, then the supporting figures below it.
Formula
Days = end − start.
Worked example
For example, with these inputs:
- Start date: 1 Jan 2026
- End date: 31 Dec 2026
the calculator returns:
- Days between: 364 days
- Weeks: 52.00 weeks
- Including end date: 365 days
Background
The Gregorian calendar has months of 28 to 31 days and adds a leap day almost every four years, which makes counting days by hand surprisingly error-prone. Converting dates to day numbers and subtracting avoids the problem.
Age is calculated in completed years, months and days. Someone born on 29 February is usually treated as turning a year older on 28 February or 1 March in non-leap years, depending on the rule being applied.
Frequently asked questions
How does the days between dates calculator work?
It applies this formula: Days = end − start.
Does this count Singapore public holidays?
No. It counts calendar days or weekdays. Subtract any public holidays in the period yourself.