Quick example
How many days are there from January 1 to February 1?
There are 31 elapsed days: four complete weeks and three days. Counting both January 1 and February 1 as included calendar days gives 32 days.
Counting convention
Elapsed days versus inclusive days
Elapsed days
Counts the midnights crossed. A date compared with itself has zero elapsed days.
Inclusive days
Counts both endpoints. A one-date range therefore contains one inclusive day.
Complete weeks
Divides elapsed days into seven-day groups and reports the remainder.
Reverse ranges
Shows the absolute span while clearly noting that the end date comes first.
Date-only arithmetic
Time zones and daylight saving do not change the answer
The calculation uses calendar dates rather than local clock times. It accounts for month lengths and leap years but does not include hours, minutes, holidays, or business-day rules.
Check your counting rule
Examples of days between dates
Dates below use YYYY-MM-DD. For a stay from March 1 to March 4, the elapsed count is 3 nights; a schedule covering both dates spans 4 calendar days.
| Start date | End date | Elapsed days | Inclusive days |
|---|---|---|---|
| 3 | 4 | ||
| 0 | 1 | ||
| 2 | 3 | ||
| 3 | 4 | ||
| 1 | 2 |
Need completed calendar years and months? Use the age calculator. For fixed-duration unit conversions, use the time converter; a calendar month is not a fixed number of days.
Common questions
Date difference FAQ
Does the date difference include both dates?
The elapsed result excludes the starting date. The inclusive result counts both dates and is always one greater than the absolute elapsed-day count. Comparing a date with itself gives 0 elapsed days and 1 inclusive day.
Does this calculator count business days?
No. It counts calendar days, including weekends and holidays. A working-day calculation also needs a workweek and a holiday calendar.
Does daylight saving time affect the result?
No. The calculator compares calendar dates without local clock times. It does not measure the actual hours between two timestamps, which can be affected by daylight saving.
Can the end date be before the start date?
Yes. The calculator reports the same absolute day count and labels the direction as backward. Reversing the dates does not change the inclusive count.
Are leap years included?
Yes. February 29 is counted in leap years. February 28 to March 1 spans 2 elapsed days in 2024, but 1 elapsed day in 2026.
Can I turn the number of days into calendar months?
Not by dividing by a fixed number. Calendar months have different lengths. The age calculator gives completed years, months, and days from a starting date.