Weeks Calculator
Count weeks between dates, with the leftover days shown.
What does Weeks Calculator do?
Work out how many complete weeks lie between two dates, plus the remaining days. Useful for pregnancy tracking, project sprints, notice periods and study plans, all of which are counted in weeks.
How to Use Weeks Calculator
- 1Pick your datesStart and end, in any order.
- 2Read the week countComplete weeks plus leftover days.
- 3Check the week numbersISO weeks for both endpoints.
Key Features
- Complete weeks plus the remaining days
- Decimal weeks for proportional planning
- ISO week numbers for both start and end dates
- Working weeks based on a five-day week
- Weeks since and weeks until modes
Frequently Asked Questions
How do I count weeks between two dates?
Count the days and divide by seven. The whole number is complete weeks and the remainder is leftover days, both of which are shown separately.
How many weeks are in a year?
52 weeks and 1 day in a common year, or 52 weeks and 2 days in a leap year. That extra day is why a fixed date shifts one weekday each year.
How many weeks are in a month?
About 4.35 on average — 30.44 days divided by seven. No month is exactly four weeks except February in a common year, which is why "four weeks" and "a month" are not interchangeable.
Why does my pregnancy week count differ?
Pregnancy weeks are counted from the last menstrual period, not from conception, and are quoted as completed weeks plus days — "12+3" means 12 complete weeks and 3 days. Follow your clinician’s dates rather than a generic calculation.
Dates and times are calculated in your browser using its built-in IANA time zone database. Nothing you enter is transmitted.
Related Tools
Days Calculator
How many days between dates, or since and until a date.
Months Calculator
Count complete months between two dates.
Date Difference Calculator
Days, weeks, months and years between any two dates.
Week Number Calculator
Find the ISO week number for any date, and vice versa.