Days Between Dates

Two answers, because there are two questions

"How many days between two dates" is asked by people who want a single number - 1,234 days - and by people who want it in a form they can say out loud: three years, four months and 17 days. Both are correct, so both are shown.

The number of days is the one you want for deadlines, notice periods and anything counted in days. The years-and-months form is the one you want for anniversaries, ages and how long something has been going on.

How the years and months figure is worked out

By walking the calendar, not by dividing. Dividing the day count by 365.25 and then by 30.44 gives a figure that looks right and quietly disagrees with the calendar - it will tell you that 15 January to 15 March is 1.9 months when any person would say two months exactly.

What this calculator does instead is count whole years first, then whole months from where that lands, then the days left over. The result always adds back up to the later date exactly, which is the property that makes it trustworthy.

The awkward cases fall out of the same rule. 31 January to 28 February is one whole month, because adding a month to 31 January clamps to 28 February. 29 February 2024 to 28 February 2025 is one whole year for the same reason.

Should the end date be counted?

It depends what you are counting, which is why it is a choice rather than an assumption.

• Leave it off to measure a gap. From the 1st to the 8th is seven days - a week.
• Turn it on to count days inclusively, which is how hotel nights, hospital stays and some contractual periods are counted. From the 1st to the 8th then gives eight.

Getting this wrong shifts every answer by exactly one, which is the most common error in date arithmetic and the hardest to spot.

Which date comes first does not matter

Put them in either order. The calculator measures the distance and tells you which way round the dates are, so "how long since" and "how long until" are the same operation. There is a swap button if you want them the other way for readability.

Frequently asked questions

How many days are between two dates?

Enter both dates and the total appears at once, along with the same span expressed in years, months and days.

How many weeks is that?

Shown in the breakdown as whole weeks plus remaining days, because "17.6 weeks" is rarely the useful form.

Does it include weekends?

Yes - every calendar day is counted. Weekdays and weekend days are listed separately in the breakdown, and if you need weekends excluded from the total, the business days calculator does that.

Does it handle leap years?

Yes. Any 29 February inside the span is counted like any other day, and spans that begin or end on a leap day use the same month-clamping rule described above.

Related date tools

Use the date calculator to go the other way and find a date from a duration, business days to exclude weekends and holidays, week numbers, and the meeting time planner across time zones.