How the sausage is made

Where every number on this site comes from

A mortgage site asking for trust owes you its working. This page states every data source we use, how often each updates, what we do when a fact can't be verified — and who pays us, because that last one explains the incentives behind everything else.

Market rates: Bank of England, checked daily

All market figures come from the Bank of England's official statistical database (IADB). We check it every few hours, but most series are monthly and published around the 5th working day of the following month, so a figure can be several weeks old — the age is shown wherever it is used:

Every figure we show carries the observation date it belongs to. The quoted-rate series are the Bank's own selection: for each loan-to-value band, the most competitive rate with the fewest conditions from Moneyfacts product data, as a headline rate with fees excluded, averaged over the month. When you give us a property value we price a comparison at your own LTV band, not the 75% figure; where the Bank publishes no band for you (5-year fixes between 75% and 95%) we say so and show the two published neighbours instead of inventing a number. We show these rates for context; we do not quote or rank individual lender deals, because we are not a comparison site and take no fee when you choose one. The current pull of every figure above is public and citable on the rate index page.

Lender rules: primary sources only, dated, or labelled assumption

The lender pages and the watch engine use the same rulebook, and it has one integrity rule: a fact is entered only when it can be read on the lender's own published pages, and it is stored with that URL and the date we checked it. Anything we cannot verify — a reset date, which balance a percentage applies to — is listed as unconfirmed and served as the market-standard assumption, clearly labelled. We would rather show you a labelled assumption than an invented fact.

Your numbers: computed, not stored — until you ask us to

The free calculators on /tools run entirely in your browser; nothing you type reaches a server. The free timeline computes on our server and stores nothing. We only keep your details when you buy a watch — that is the product — and the privacy page lists exactly what that means.

The engine

Projections use standard level-payment amortisation on monthly rests. Timeline events are derived from your deal's own terms: early repayment charge step-downs from the dates in your offer, overpayment allowance resets from your lender's rule (or the labelled assumption), the early-lock window from your lender's published product-transfer window where verified and a 6-month market assumption where not. Every event says which it is. House-price-indexed estimates are always labelled as estimates.

Who pays us — and who doesn't

You do: from £5.99, once per deal, no card kept on file. Nobody else does: no lender commission, no broker referral fees, no advertising, no selling data. Most free mortgage-alert services are funded by the broker or lender you end up switching through, which shapes what they nudge you towards. Our only incentive is that the dates and sums we send you are right.

What we are not

We are not regulated financial advisers and we do not give advice — the site computes facts about your own deal and the market and puts dates on them. For advice on a decision, speak to a mortgage adviser regulated by the FCA. If you spot a figure we've got wrong, or a lender rule that has changed, tell us — a correction with a source is the most useful email we can receive.