What this calculator does
Weeks between dates is a more specific question than a plain day count: it wants the span expressed in whole weeks, with whatever is left over shown as a handful of days. Enter two dates and this calculator gives exactly that, a figure such as "12 weeks, 6 days", alongside the same span as a single decimal number of weeks.
Calculating weeks between two dates by hand means dividing a day count by 7 and working out the remainder, which is easy to get wrong across a long span or a date that crosses several months. This calculator does the division and the remainder in one step, so the whole-weeks-and-days figure and the decimal figure are always consistent with each other.
The formula
The total number of days between the two dates is found first, then divided by 7. The whole number of weeks that fit is shown alongside whatever days are left over, and the same total is given again as a single decimal figure, days divided by 7.
| Term | Meaning |
|---|---|
| First date | The earlier of the two dates being compared. |
| Second date | The later of the two dates being compared. |
| Whole weeks | The number of complete 7-day weeks that fit within the total day count. |
| Remaining days | Whatever days are left over once the whole weeks are counted, always fewer than 7. |
The inputs explained
| Field | What to enter |
|---|---|
| First date | The first date. Defaults to today. |
| Second date | The second date to calculate weeks between dates to. |
When to use it
How many weeks between two dates for a project or booking
A project timeline, a booking window or a training plan often runs in weeks, and this figure converts a start and end date straight into that unit.
Calculate weeks between dates for a pregnancy or medical timeline
Weeks are the standard unit for tracking a span from one date to another in a medical or health context, where whole weeks plus a few days is the expected way to state progress.
Comparing a weeks figure against a plain day count
Some contexts quote a span in days and others in weeks; having both from the same two dates avoids running the sum twice and getting a mismatch.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the weeks-between figure grows as the second date moves further out
A series of second dates, each measured back to today in whole weeks, remaining days, and as a decimal.
| Second date | Whole weeks and remaining days | As a decimal figure |
|---|---|---|
| today+7 | 1 weeks, 0 days | 1.00 weeks |
| today+14 | 2 weeks, 0 days | 2.00 weeks |
| today+30 | 4 weeks, 2 days | 4.29 weeks |
| today+60 | 8 weeks, 4 days | 8.57 weeks |
| today+90 | 12 weeks, 6 days | 12.86 weeks |
| today+180 | 25 weeks, 5 days | 25.71 weeks |
Questions
How many weeks between two dates?
Enter the two dates as the first and second date; the calculator gives the whole number of weeks between them plus any remaining days, and the same total again as a single decimal figure.
How do I calculate weeks between dates that are not in order?
Enter them in either order. If the first date entered is later than the second, they are swapped automatically so the count still runs forward in time.
Weeks between dates versus days between dates: which should I use?
Both come from the same underlying day count. Use weeks between dates when a span is more naturally described in whole weeks, such as a project sprint or a training block; use the days calculator when a plain day count is what is actually needed.
Why is the decimal figure not a round number even when the whole weeks are exact?
The decimal figure is only round when the total day count divides evenly by 7. Any leftover days, shown separately as the remainder, appear in the decimal as a fraction of a week rather than rounding away.
For a fuller breakdown including years and months, see the time between dates calculator. For a plain day count between two dates, use the days calculator.