Date Difference

Count the days, weeks and months between two dates. Free, runs entirely in your browser — no signup, and nothing you paste in is uploaded.

Days between dates is the only part that is simple arithmetic; months are not, because they vary in length. The gap from 31 January to 28 February is one month by one convention and not by another, and any tool has to pick a rule and apply it consistently.

Two details cause most disagreements about a count. Whether the calculation is inclusive of both endpoints — which is why a hotel stay and a project duration count differently — and daylight saving, where two dates a month apart are not exactly 720 hours apart in any timezone that shifts.