# finance.uk-bank-rate
The Bank of England's Bank Rate (the "base rate", and the "official dealing
rate" in older legislation) in force on a date. Statutory interest, tracker
mortgages and loan agreements are all written as a margin over it, and all of
them need the rate on a particular past date, not today's.
The rates are dated rows in `data/bank-rate.json`, one per change, each in force
from the day of the change to the day before the next. They run from the cut to
4% on 8 November 2001 (so the rate on any date from then on is known) to the cut
to 3.75% on 18 December 2025, which was still in force when this version was
published. A date before 8 November 2001 is refused rather than guessed.
Source: Bank of England, "Official Bank Rate history",
https://www.bankofengland.co.uk/boeapps/database/Bank-Rate.asp, checked on
23 September 2026 (no change in 2026 up to that date). Rates are held in basis
points, which every published rate fits exactly (0.1% is 10).
When the rate changes, publish a new version with the new row and the previous
row's `validTo` filled in. The data declares its effective dates, so a
`history=current` build ships only the rate still in force and refuses an
earlier date, explaining why, rather than answering it with today's rate.