Each one works out a single decision — overpay the mortgage or invest, fix for two years or five — under assumptions you can see and change, then stops. No signup, no adverts, nothing to install, and nothing about your money ever leaves your browser.
More are coming, roughly one a week — fixing for two years or five is next. What gets built next is decided by the vote at the bottom of each tool, so it is worth using.
One person building a free calculator every few weeks, and honest notes about which of them worked. The next one goes to this list first.
Being straight with you: these are experiments. Some will be abandoned and the bigger thing behind them may never get built. One email a fortnight at most, unsubscribe in a click, no selling. You will get a confirmation email first — your address is not added until you click the link in it.
Every tool here shows arithmetic under assumptions you can see and change — never a recommendation, never a ranked “best option”. This is information, not financial advice, and regulated advice is worth getting before a decision this size.
Because I am finding out which of these decisions people actually want help with. Each tool is real and useful on its own, and each is also a question: does anyone need this? Some will be kept and built out further. Some will be dropped. The longer version is here, including what happens to the ones that get dropped.