How we build these

Every figure on this site comes from a method you can check. This page sets out how each type of tool works and where its data comes from.

Date and time calculators

All date maths runs in UTC on whole calendar days. That sounds fussy, but it is the reason a clock change never adds or drops a day in a result. A count from March to April is the same number whether or not the clocks moved in between.

Years and months are counted as real calendar units, not as fixed blocks of 30 or 365 days. The calculator steps down through actual months, so the answer matches the way you would say it out loud. Leap years fall out of this correctly, including birthdays on 29 February.

Nothing you type is sent anywhere. The maths happens in your browser.

Working days and bank holidays

Working days mean Monday to Friday. Saturdays and Sundays are excluded.

Bank holidays are optional, because they differ across the UK and because plenty of contracts define their own holiday list. When you pick a region, the dates come from the official gov.uk bank holidays feed, covering England & Wales, Scotland and Northern Ireland separately. That feed is the authoritative source, which matters more than it sounds: substitute days (when Christmas falls on a weekend, say) are easy to get wrong from memory, and the official list settles it.

The holiday data is refreshed against gov.uk each year.

Word lists

The words come from the Datamuse language API, which returns words matching a spelling pattern along with how often each one appears in written English.

That raw output needs cleaning before it is any use, so each list is filtered:

• Checked against an English dictionary, so real words stay and invented strings go.
• Frequency floor for anything not in the dictionary, which keeps common inflections (words like “questions” or “planning”) while dropping obscure noise.
• Roman numerals removed. Without this, a page of words starting with X is mostly xi, xii, xiv and xvi, which is useless to anybody.
• Fragments and abbreviations removed: single and double letters, and strings with no vowel.

What survives is ranked by frequency, so the words people actually use sit at the top rather than being buried under rarities. Each list holds up to 500 words.

Some proper nouns still get through, particularly on sparse letters like X and Z where there are few common English words to draw on. We would rather show you Xerox and Xenon than an empty page.

When lists are short

A few patterns genuinely have very few English words. Those pages are kept for completeness and marked as short rather than padded out with junk to look fuller.

Getting it wrong

Some of this will be wrong somewhere. If you spot a bad answer or a missing word, tell us and it gets fixed.