Day Counter
Count the number of days between two dates.
Try an example
364 days
About this calculator
How This Day Counter Works
Enter a start date and an end date, and the calculator returns the number of days between them — with an option to include the end date itself in the count.
Worked Example
From January 1 to December 31, 2026, there are 364 days between the two dates — or 365 days if the end date is included in the count.
Why the Count Can Differ by One Day
Counting the span between two dates (like the number of nights between a check-in and check-out) gives a different number than counting every calendar day including both endpoints (like counting each day of a vacation, arrival and departure both included). This is one of the most common sources of off-by-one confusion in date math — this calculator's toggle switches between the two interpretations explicitly.
Day Counter vs. Date Calculator
This tool solves the opposite problem from the Date Calculator: instead of adding or subtracting time from a single date, it counts the days between two dates you already know — useful for tracking how long a project took, how many days until an event, or verifying a deadline calculation.
Worked example
From January 1 to December 31, 2026, there are 364 days between the two dates (365 if the end date itself is included in the count).
Frequently asked questions
Why might the count be off by one from what I expected?
It depends on whether you're counting the span between two dates or the number of calendar days including both endpoints. Use the 'include end date' option to switch between the two.
Can I count days backward from a future date?
Yes — enter the later date as the start and the earlier date as the end; the result reflects a negative span, showing how many days before the start date the end date falls.
How is this different from the Date Calculator?
The Date Calculator adds or subtracts an amount of time from one date to find another. This tool goes the other direction — given two known dates, it counts the days between them.