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Week number
The ISO week for a date, or the seven dates of a week.
It runs entirely in this browser tab: what you type is never uploaded, and the tool makes no network request while it works. Open your browser's network panel and try it — nothing leaves the page. There is no sign-up and no account.
Settings
- Month before day
- Only for a date like 03/04 — a four-digit year first is never ambiguous.
How to use it
- Paste your text into the box above, or open a file.
- Adjust the settings beside it until the result is what you wanted.
- Copy the result, or save it as a file. The result updates as you type.
Questions
- Is 03/04/2024 the third of April or the fourth of March?
- Both, and no parser can tell. Every tool that reads a date has a setting for the order, and a four-digit year first is never ambiguous whatever the setting says. The format converter goes further: it counts the dates in a column that can only be read one way, and warns when the column disagrees with itself.
- Are the public holidays accurate?
- They are rules rather than dates — a fixed day, an offset from Easter, or the nth weekday of a month — so they work for any year. They are not a legal source: holidays are moved, added and removed by decree, and regional ones are not here at all. Every result that uses them says so.
- Does it know about time zones?
- No, deliberately. A time-zone database is several megabytes, larger than this whole application, and it is revised several times a year — a stale copy would put a meeting an hour out for half of Europe every spring. The meeting planner takes offsets from you and says it knows nothing about daylight saving.
- Is what I type uploaded anywhere?
- No. This page carries the whole tool as WebAssembly and runs it on your own device. Nothing you type is sent anywhere.
Other tools for the calendar
Day of the week
Which weekday a date was, and where it sits in its year.
Leap year
Whether a year is one, and the century rule that decides it.
Easter date
Easter Sunday and the twelve feasts that hang off it, in both churches.
Public holidays
A year of holidays for seven countries, with the long weekends marked.
Julian date
The three different things called a Julian date, side by side.
All twenty-five tools