Days Between Two Dates Calculator
Find how many days lie between two dates, with or without counting both ends. The span is also shown in years, months and days, in weeks and in hours, with the number of Saturdays and Sundays.
- In years, months, days1 month 30 days
- In weeks and days8 weeks 4 days
- Whole months1
- About this many years0.16
- Total hours1,440
- Saturdays and Sundays16 days
How it is calculated
The day difference counts the nights from one date to the other: today to tomorrow is 1 day. For contract, rent or hotel stays where both ends count, choose “both days included”. Months and years vary in length, so “how many months” is answered exactly as whole months plus days; the decimal years figure is an approximation. Legal deadlines skip the starting day and extend when the last day is a holiday; use the due date calculator for those.
Days = N(end) − N(start) (+1 when both days count)N: the date’s day number from a fixed day (1 January 1970), counting leap years (every 4th year, except century years not divisible by 400). In years-months-days, a month runs from the start’s day number to the same number; if the month lacks it, its last day is used.- Find both dates’ day numbers.
- Subtract; add 1 to count both days.
- Divide by 7 for weeks; the remainder is the extra days.
- Divide by the average Gregorian year (365.2425 days) for approximate years.
Example
There are 364 days (52 weeks) from 1 January to 31 December 2025, or 365 counting both days. From 15 March 1990 to 9 July 2026 there are 13,265 days: 36 years, 3 months, 24 days.
Frequently asked questions
Are the start and end days counted?
The default “difference” leaves out the start day and counts the end day (today to tomorrow is 1 day). “Both days included” adds 1.
Are leap years taken into account?
Yes. Every year with a 29 February counts 366 days; 2000 was a leap year, 2100 will not be.
How do I count working days between two dates?
Use the working days calculator, which leaves out weekends and public holidays and can also handle half days and public-sector leave days.