Weeks Between Dates Calculator

This weeks between dates calculator shows how many full weeks (and leftover days) separate two dates — the "X weeks, Y days" format used for pregnancy dating, training plans and project sprints.

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Weeks between

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Standard clock & calendar math. For payroll, verify against your employer's rounding policy.

How weeks between dates are counted

The calculator first counts the exact days between your two dates, then divides by 7: the whole-number part is your full weeks and the remainder is the leftover days. That "X weeks, Y days" format is exactly how pregnancy is dated and how coaches write training blocks. The table also shows the same gap as a decimal week count and as calendar months.

Worked example: a 12-week pregnancy milestone

Say the first day of the last menstrual period was January 5, 2026 and today is March 30, 2026. The exact gap is 84 days. Dividing by 7 gives 12 full weeks, 0 days — written as a decimal that is exactly 12.00 weeks. Because 84 days isn't a whole number of calendar months, the same span reads as 2 months and 25 days on a monthly calendar, which is why gestational age is always tracked in weeks rather than months.

Full weeks and leftover days at a glance

Gap between dates	Total days	Full weeks + days	Decimal weeks
10 days	10	1 wk 3 d	1.43
One calendar month (Jan 1 → Feb 1, 2026)	31	4 wk 3 d	4.43
One quarter (Jan 1 → Apr 1, 2026)	90	12 wk 6 d	12.86
Half a year (Jan 1 → Jul 1, 2026)	181	25 wk 6 d	25.86

Full weeks use whole-number division and never round up: 90 days is 12 full weeks with 6 leftover days, not 13 weeks. Use the decimal column when a spreadsheet needs weeks as a single number, and the full-weeks column for pregnancy, sprints or training blocks.