How many days between two dates?
Enter a start and end date to get the exact number of days, weeks, and months between them.
How to use the days between dates calculator
Choose a start date and an end date to calculate the exact elapsed time between them. The result gives the number of days and also summarizes the span in weeks and months, which is useful for planning trips, projects, contracts, milestones, and personal events.
This calculator uses an exclusive day count: it measures the full days between the two dates. If you need to include both the start and end date in a schedule, add one day to the displayed total.
Inclusive vs. exclusive counting — a detail that trips people up
There are genuinely two correct ways to count the "distance" between two dates, and mixing them up is one of the most common sources of off-by-one errors in scheduling. An exclusive count (what this calculator shows by default) measures the number of full days that pass between the start and end date — from January 1st to January 10th is 9 days exclusive. An inclusive count adds one, treating both the first and last day as counted days — the same range is 10 days inclusive. Legal notice periods, rental agreements, and "X-day" return policies often specify which convention applies, and getting it wrong by one day has real consequences in those contexts, so it's worth checking the specific document's wording rather than assuming.
Why elapsed time isn't always a clean number of weeks or months
Because months vary from 28 to 31 days, converting a day count into "months" is inherently approximate unless you're measuring between the exact same day-of-month in consecutive months. This calculator shows the precise day count first and a reasonable week/month approximation alongside it — for legal or financial calculations where the exact month count matters, it's safer to count from calendar date to calendar date rather than relying on a days-to-months conversion.
Common uses
This calculator gets used most often for measuring the length of a trip or project, checking how many days remain in a lease, warranty, or return window, calculating elapsed time for medical or legal purposes (like a required waiting period), and general curiosity about how much time has passed between two personal milestones.
Related tools: Add or subtract days from a date · Count business days instead · Calculate an exact age
Frequently asked questions
Does this include both the start and end date?
We count the number of full days between the two dates (exclusive count). If you need an inclusive count, add one day to the result.
Can I use this for contracts or deadlines?
Yes — it's commonly used for lease terms, notice periods, and project timelines. For legal deadlines, always confirm with the relevant authority or document, and check whether it specifies inclusive or exclusive counting.
Why doesn't the "months" figure match what I expected?
Because months have different lengths, a day count doesn't translate to a clean month count unless the two dates share the same day-of-month. Treat the months figure as a helpful approximation, and use the exact day count for anything precise.
Inclusive versus exclusive counts
Hotels often count nights, not calendar dates. Project plans sometimes include both the start and the end date. If 1 June to 3 June is “two days later” in ordinary speech, it is three dates on a wall calendar. Read the result label on this page before you copy the number into a contract.
Example: 1 January 2026 to 1 February 2026 is 31 days later if you exclude the start date and measure elapsed midnights. Including both calendar dates produces 32. The tool shows which mode it uses so the off-by-one is visible.
Time of day
This calculator is date-based. It does not subtract hours and minutes. For a flight that leaves at 23:00 and lands after midnight, a duration tool with times is more accurate than a date-only span.