Date & Time
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Weeks Between Dates Calculator
Find how many weeks are between two dates — useful for pregnancy weeks, project sprints, payroll cycles and countdowns. Enter a start date and an end date and the calculator divides the total days by seven to give the whole weeks, and also shows the total days and a calendar year/month/day breakdown so you can read the exact remainder. For example, 1 January 2026 to 31 January 2026 is 30 days, which is 4 whole weeks and 2 days. The math runs on UTC midnights so a day is always a full calendar day regardless of a daylight-saving change, and everything is computed in your browser. Dates entered in the wrong order are order-normalized to a positive result.
Weeks = floor(total days / 7)
- 1 Jan 2026 → 31 Jan 2026 = 30 days = 4 weeks and 2 days
- Total days and a calendar year/month/day breakdown are shown alongside
Frequently asked questions
How many weeks are between two dates?
Divide the total number of days between the dates by seven and take the whole number. From 1 January 2026 to 31 January 2026 is 30 days, which is 4 whole weeks and 2 remaining days. The calculator shows the whole weeks plus the exact day count.
How do I count weeks for pregnancy or a project?
Enter the start date (for example the last menstrual period or the project kickoff) and the end date, and read off the whole weeks. The tool also shows the leftover days so you can express the span as, say, 12 weeks and 3 days.