Date Difference Calculator: Days Between Dates
Days, weeks, months and business days between two dates.
Use via API
Time between two dates in years, months and days, plus total days, weeks and business days (Monday–Friday). Send JSON, get JSON back.
POST https://pithlab.com/api/v1/tools/date-difference-calculator
curl https://pithlab.com/api/v1/tools/date-difference-calculator \
-H "Authorization: Bearer $PITHLAB_KEY" \
-H "Content-Type: application/json" \
-d '{"start":"2026-01-15","end":"2026-10-20"}'About the Date Difference Calculator
Count the days between two dates, as years, months and days, total days and weeks, plus business days (Monday to Friday). Leap years handled.
How to use the Date Difference Calculator
- Pick the start date (it starts as today) and the end date.
- Tick “Include end date” if both the first and last day should count, as for a holiday or a booking.
- Read the difference in years, months and days, the total days and weeks, and the number of business days.
Examples
Input
2024-01-15, 2024-03-01
Output
From 2024-01-15 to 2024-03-01: 1 month, 15 days (46 days, 34 business days)
Input
2026-01-01, 2026-12-31, include end date
Output
From 2026-01-01 to 2026-12-31 (end date included): 1 year (365 days, 261 business days)
Frequently asked questions
Is the end date counted?
Not by default: from Monday to Friday is 4 days, the way you'd count nights. Tick “Include end date” to count both ends, which makes Monday to Friday 5 days.
What counts as a business day?
Any Monday to Friday. Public holidays aren't removed because they differ by country and region, so subtract any that fall in your range.
How are months counted when they have different lengths?
Whole months are counted from the start date, then the remaining days. If the start day doesn't exist in a month, the last day of that month is used: 31 January to 28 February 2026 is one month.