About | Universal Week Number

Why this exists

Many week number pages bury the answer under pop-ups, ask you to sign up or never say which numbering rule they use. Universal Week Number does one thing differently: it shows the current and any other week number instantly and for free, states its rule openly (ISO 8601) and has nothing to sign up for.

How the calculator works

Your dates are processed entirely inside your own browser, using standard JavaScript. Nothing you enter is ever transmitted to any server — not even anonymised. Once the page has loaded, you can disconnect from the internet and the calculator works just the same.

How it stays free

This site is supported by advertising. There is no premium tier and no feature held behind a paywall — the ads are what make every part of the tool free and unlimited.

Privacy by design

Dates can say a lot about you — a due date, a trip, a contract, a shift plan. This tool was built so that it cannot see them: the code runs in your browser, the results stay in your browser, and no date leaves your device. There are no analytics that track what you entered.

Part of the Universal family

Universal Week Number is one of several free utility tools built on the same principle: solve one real problem well, keep it free, and respect your time. All tools share the same clean, fast design with no dark patterns, no upsells, and no friction.

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