Years and months move first
Years, then months, then weeks and days. The order matters: one month after 31 January is 28 February, and thirty days after it is 2 March. Both are correct answers to different questions.
Date Calculator 📅
Pick a date, say how far to move and in which direction, and read the answer. Days, weeks, months and years can be combined, before or after, and the result is marked on a calendar so you can see the week it falls in. The answer updates as you type — there is nothing to submit.
Days · weeks · months · years
Before or after
Calendar view
Nothing leaves your device
Result
Start date
Result
Today
How the arithmetic works
Date arithmetic looks simple and is not, because months are not all the same length. These are the rules this tool follows, so you can check that the answer is the one you meant.
A short month clamps to its last day
There is no 31 February, so one month after 31 January lands on the 28th — the 29th in a leap year. Every calendar behaves this way. When it happens, the tool says so instead of silently spilling into the next month.
A week is always seven days
Weeks and days are counted as plain days, so they never clamp. Weekends and public holidays are counted too — this is a calendar-day tool, not a working-day one.
Nothing leaves your device
The calculation runs in your browser. No date you type is sent anywhere, saved or logged, and the page works with the network switched off once it has loaded.
Counting the days to an examination?
We build revision timetables backwards from the date that matters. Tell us when the paper is and we will tell you what each week needs to cover.