Find the exact time between two dates
Enter a start date and an end date to see the exact number of days, weeks, and a full years/months/days breakdown.
Common day-count conversions
Quick reference for how common day counts translate to weeks, months, and years.
| Days | Approximate length |
|---|---|
| 7 days | 1 week |
| 30 days | ≈ 1 month |
| 90 days | ≈ 3 months |
| 180 days | ≈ 6 months |
| 365 days | 1 year |
| 730 days | 2 years |
Want the exact difference between two real dates? Use the date difference calculator above.
About the date difference calculator
This calculator finds the exact amount of time between any two dates — as a total day count, a total week count, and a full years/months/days breakdown. Enter a start date and an end date, in either order, and it works out how much time separates them, automatically handling the case where the end date falls before the start date by taking the absolute difference and noting the direction.
The total-days figure is the most precise way to compare two dates, since it's just a straight count of days between them with no rounding or approximation. From there, the calculator also expresses that same span in whole weeks (with any leftover days), which is handy for anything measured in weeks — pregnancy, project sprints, or countdowns to an event.
The years/months/days breakdown is more involved than it looks, because calendar months don't all have the same number of days. Simply subtracting years, months, and days independently can produce a negative day count whenever the end date falls earlier in the month than the start date. This calculator resolves that the same way you'd do long subtraction by hand — borrowing a month's worth of days when needed, and a year's worth of months when needed — so the years, months, and days shown always add up to the correct total.
Because it works with real calendar dates rather than a fixed 365-day year, the calculation automatically accounts for leap years and the varying lengths of different months. That makes it accurate for both short gaps (a few weeks between two deadlines) and long ones (decades between two historical dates).
This page also includes reference conversions for common round day counts — for example, how many weeks or months roughly correspond to 100 days or 365 days — which is useful shorthand even when you don't have two specific calendar dates in mind, just a duration you're trying to picture.
Date difference calculator questions
How the days, weeks, and years/months/days breakdown are calculated.
How do I find the number of days between two dates?
Enter a start date and an end date. The calculator subtracts one from the other and shows the exact total number of days between them, along with a breakdown in weeks and in years/months/days.
What happens if I enter the end date before the start date?
The calculator still works — it takes the absolute difference between the two dates and shows a note indicating that the "end" date actually comes before the "start" date, rather than showing a negative result.
Why doesn't the years/months/days breakdown match a simple subtraction?
Because calendar months have different lengths, subtracting year, month, and day components independently can produce a negative day count. This calculator borrows a month's worth of days (and a year's worth of months) where needed, the same way you'd do long subtraction by hand, so the breakdown always adds up correctly.
How many weeks is a given number of days?
Divide the total days by 7 to get whole weeks, with any remainder shown as leftover days. For example, 100 days is 14 weeks and 2 days.
Does this calculator account for leap years?
Yes. Because it works directly with real calendar dates instead of assuming a fixed 365-day year, leap years and the extra day in February are automatically factored into every result.
How accurate is converting a day count into months or years?
It's an approximation. Since months and years don't have a fixed number of days, this calculator uses average figures (about 30.44 days per month and 365.25 days per year) for round day-count conversions. For two specific calendar dates, the exact years/months/days breakdown above is more precise.
Can I use this to count down to a future event?
Yes — set the start date to today and the end date to the event date. The total days and weeks shown will tell you exactly how far away it is.
Can I use this to calculate someone's exact age?
You can, by entering a birth date as the start date and today (or any other date) as the end date — though the dedicated birthday calculator also adds zodiac sign and days-until-next-birthday if that's what you're after.