How this instrument works
Some calculations only ever want one number: the exact count of days between two dates, with no years-months-days breakdown attached. That's the figure behind a contract's day-count term, a notice period measured in days, a warranty window, or the day-count conventions — such as Actual/365 or Actual/360 — that finance uses to compute interest accrued between two dates.
Because it counts actual calendar days on the civil (Gregorian) calendar rather than assuming every month or year is the same length, it automatically absorbs leap days — a span crossing 29 February in a leap year is one day longer than the identical month-and-day range in a non-leap year, and this instrument reflects that without you needing to check a leap-year table.
For the same span expressed with a years/months/days breakdown instead of a single total, see Day Counter; for the same total-days figure specifically anchored to a birth date, see Age in Days.
- Enter the start date.
- Enter the end date — any date on or after the start date.
- Read Days between the two dates beneath the two fields.
- The start date must be on or before the end date.
Worked example — 29 February 2024 to 28 February 2025
Enter 29 February 2024 as the start date and 28 February 2025 as the end date. Days between the two dates reads 365.
2024 is a leap year, so the span opens on the leap day itself; a year later, 2025 is not a leap year and has no 29 February to land on. The two dates come out exactly 365 days apart — the same length as a standard non-leap calendar year — even though the span starts on a date, 29 February, that doesn't exist most years.
Questions
Why does the leap-day example come out to exactly 365 days, not 366?
Because the span runs from 29 February 2024 to 28 February 2025, and the only 29 February inside that window is the starting day itself — the next one doesn't arrive until 2028. A span that instead ran from 28 February to the following 1 March in a leap year would pick up that extra day and read 366.
What's a day-count convention, and how does this relate?
Day-count conventions (Actual/365, Actual/360, 30/360 and others) are standardized methods finance uses to compute interest accrued between two dates. The 'Actual' methods use the real calendar day count this instrument computes directly; the '30/360' methods instead assume every month is 30 days, which can give a slightly different total for the same two dates.
Does the count include the start date, the end date, or both?
It's the number of days elapsed between them — like counting nights between two dates on a calendar — so the start date is day zero and the count runs up to, and includes, the end date as the final day counted.
Is this the right number for a notice period or contract deadline?
It's the raw calendar-day count, which is what most 'X days' notice periods and contract terms mean by default. Always check the specific contract or regulation for whether it means calendar days (what this instrument gives) or business days, which would need weekends and holidays excluded separately.
How is this different from Date to Date?
The math is identical — this instrument just reports the single days total, where Date to Date also reports the same span as a rounded-down weeks total alongside it.