Weeks Between Two Dates
Count the exact number of weeks between any two calendar dates, broken down into full weeks, leftover days, and a precise decimal total.
25 full weeks + 2 days
- 1
Days between dates
177⌊|end − start| ÷ 86,400,000 ms⌋ — partial days are dropped. - 2
Full weeks
⌊177 ÷ 7⌋ = 25 - 3
Remaining days
177 mod 7 = 2 - 4
Decimal weeks
177 ÷ 7 = 25.29
How does this calculator work?
Subtract the start date from the end date, take the absolute value, and divide the resulting whole days by 7. The integer part is full weeks, the remainder is leftover days, and the full quotient is the decimal week count. Date order does not matter and partial days are ignored.
Formula
How this is calculated
Enter a start date and an end date in any recognizable format (for example YYYY-MM-DD). Each date is parsed into a millisecond timestamp, and the calculator takes the absolute difference so the order of the two dates never matters — you always get a positive result.
The difference in milliseconds is divided by 86,400,000 (the number of milliseconds in a day) and floored to give the total whole days. Total days is then split into full weeks (the integer quotient of days ÷ 7) and remaining days (the remainder, 0 to 6). The decimal week count is simply total days ÷ 7, which keeps the fractional part for a continuous measure.
This uses calendar-day differences, so partial days are dropped by the floor operation, and daylight-saving shifts can affect dates near a clock change since parsing assumes the local time zone. Identical start and end dates return zero weeks and zero days.
Frequently asked questions
No. The calculator uses the absolute difference, so swapping the start and end dates gives the same number of weeks and days.
Full weeks is the whole-number count of complete 7-day periods, with the leftover shown as remaining days. Decimal weeks expresses the same span as a single fractional number, for example 3.5 weeks instead of 3 weeks and 4 days.
No. The total-day count is floored, so any time-of-day component is dropped and only whole calendar days contribute to the week totals.
Also known as
TG we-Calculate Editorial Team. (2026). Weeks Between Two Dates [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/weeks-between-dates
TG we-Calculate Editorial Team. "Weeks Between Two Dates." TG we-Calculate. 2026. https://we-calculate.com/calculator/weeks-between-dates.
TG we-Calculate Editorial Team, "Weeks Between Two Dates," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/weeks-between-dates
@misc{wecalculate_weeks_between_dates, title = {Weeks Between Two Dates}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/weeks-between-dates}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?