Days between two dates, in days, weeks, months and years
Enter a start date and an end date to see the number of days between them, plus the same span in weeks, in years, months and days, and in weekdays. The start date is not counted: from March 1 to March 2 is one day.
Inputs used by this calculator
Date Calculator uses the fields below. The starting values reproduce the page example; replace them with values from the same units and time period before using the result.
| Input | Starting example | Accepted value | How it is used |
|---|---|---|---|
| Start date | 2026-01-01 | Text in the format shown | Supplies the start date quantity used by the published equation or result breakdown. |
| End date | 2026-12-31 | Text in the format shown | Supplies the end date quantity used by the published equation or result breakdown. |
Counting the days between dates
The answer is the end date minus the start date in whole calendar days. The start date is day zero, so there is one day between Monday and Tuesday. If the end date is earlier than the start date, the result is negative, which tells you how many days ago it was.
Years, months and days
The calendar breakdown counts whole years first, then whole months, then the remaining days, the same way an age is counted. Because months have 28 to 31 days, the same number of days can be a different number of months depending on when the span starts.
Leap years
A leap year adds February 29. The U.S. Naval Observatory states the Gregorian rule: years divisible by 4 are leap years, except century years, which must also be divisible by 400. So 2000 was a leap year, 1900 was not, and 2028 will be. The day count includes every February 29 in the span.
Including the start or end date
Some questions count both dates, such as the number of days in an event that runs from the 3rd to the 7th: that is five days, one more than the difference. Add one to the result in that case, or use the Day Counter, which lets you include or exclude each end.
Weekdays between dates
The weekday row counts Monday through Friday after the start date up to and including the end date. Holidays are not removed, because they depend on the employer, bank, court or government office involved.
Time zones and daylight saving time
The calculation works on calendar days, not hours. Days when clocks change for daylight saving time still count as one day each, so the answer does not drift by an hour or a day in spring and fall.
Days in each month
| Month | Days |
|---|---|
| January | 31 |
| February | 28, or 29 in a leap year |
| March | 31 |
| April | 30 |
| May | 31 |
| June | 30 |
| July | 31 |
| August | 31 |
| September | 30 |
| October | 31 |
| November | 30 |
| December | 31 |
Frequently asked questions
How many days are between two dates?
Subtract the start date from the end date. The calculator counts whole calendar days and does not count the start date.
Is the start date included?
No. Add one if your question counts both the first and the last day.
Does it account for leap years?
Yes. Every February 29 inside the span is counted.
Why is the result negative?
The end date is earlier than the start date; the number shows how many days back it is.
How many weeks are between the dates?
The result shows whole weeks and the days left over, such as 12 weeks, 6 days.
Are holidays excluded from the weekday count?
No. Weekdays are Monday through Friday; holidays depend on the calendar you follow.
How is this different from the Day Counter?
This page gives the span in several units. The Day Counter adds options to include or exclude the start and end dates and to count weekdays only.
What to keep in mind
The start date is excluded. These are calendar days, not business days or elapsed local hours.
Results are rounded for display in US format, with money in dollars and cents; CSV exports keep full calculation precision. This is a calculation summary, not an official certificate.