Weeks Calculator - Count Weeks Between Two Dates

Milestones measured in weeks

Context	Weeks	Days	Why it matters
Full-term pregnancy	40	280	Measured from last menstrual period
US college semester	15-16	105-112	Including exam week
Couch to 5K program	9	63	3 runs per week
Notice period (typical)	2-4	14-28	Varies by contract and country
Sprint cycle (Agile)	2	14	Most common sprint length
Calendar year	52	365	52 weeks and 1 day (2 in leap years)

The Weeks Calculator takes two dates and returns the gap in complete weeks plus any leftover days. It works both ways - the order of dates does not matter.

Real-world examples

Pregnancy tracking
Last period: Jan 6 - Due date: Oct 13
Result: 40 weeks and 0 days (280 days)

Project deadline
Kickoff: Mar 3 - Delivery: Jun 9
Result: 14 weeks and 0 days (98 days)

Fitness challenge
Start: Apr 1 - End: Jun 24
Result: 12 weeks and 0 days (84 days)

Lease duration
Move in: Sep 1 - Move out: Aug 31 (next year)
Result: 52 weeks and 1 day (365 days)

Vacation countdown
Today: Jun 23 - Flight: Aug 15
Result: 7 weeks and 4 days (53 days)

How to count weeks between dates - step by step

Start date - pick or type the first date in YYYY-MM-DD format.
End date - pick or type the second date.
Show remaining days - leave checked to see "12 weeks and 3 days" instead of just "12 weeks."
Read the results - total weeks, leftover days, total days, total hours, and approximate months.

Weeks per month - quick reference

Month	Days	Full weeks	Extra days
January	31	4	3
February	28/29	4	0/1
March	31	4	3
April	30	4	2
May	31	4	3
June	30	4	2

No calendar month contains exactly 4 weeks. February in a non-leap year comes closest at 28 days (4 weeks, 0 extra days).

How many weeks are in a year?

A common year has 52 weeks and 1 day (365 days). A leap year has 52 weeks and 2 days (366 days). Neither fits into an exact number of weeks.

How do I calculate which pregnancy week I am in?

Enter the first day of your last menstrual period as the start date and today's date as the end date. The result shows your current pregnancy week. At 40 weeks, the estimated due date arrives.

Does the order of dates matter?

No. The calculator always uses the earlier date first internally, so entering dates in reverse order gives the same result.

What does "show remaining days" do?

When checked, the result includes leftover days: "12 weeks and 3 days" instead of "12 weeks." Useful when the exact day count matters - for pregnancy tracking, project planning, or contract terms.

Can I count weeks including today?

The calculator counts the difference between two dates, not including the start date itself. If you need to include day 1, set the start date to one day earlier.

How is this different from the Day Counter?

The Day Counter returns total days. This calculator divides by 7 and shows full weeks plus remainder - more natural for pregnancy, fitness plans, and sprint cycles.

Related tools

Duration Calculator

Measure elapsed time between two clock times in hours and minutes - Open calculator

Time Zone Difference

Find the absolute gap between two clock readings - Open calculator

Day Counter

Count the number of days between two dates - Open calculator

Date Difference Calculator

Find the gap between two dates in years, months, weeks and days - Open calculator

Date Calculator

Add or subtract days, weeks, months from any date - Open calculator