Branchsum is one person building free calculators for the UK money decisions that are slow or costly to undo, and finding out which ones anybody actually wants.
Every tool here is real and finished enough to be useful on its own. Each one is also a question: is this worth building further? I put one out, see whether anyone uses it, and decide from that.
Which means some of these will be abandoned. Not neglected quietly — actually stopped, because not enough people needed them. I would rather say that plainly on this page than have you find out when a calculator you liked stops being improved.
There is a bigger idea behind the small ones. It might never get built. If it does, it will be because the small ones showed there was something worth building, and the people on the email list will hear about it first.
In the UK, recommending a course of action on a mortgage, investment or pension is a regulated activity. Every tool here shows arithmetic under assumptions you set and stops there — never “you should”, never a ranked best option. This is information, not financial advice. For a decision this size, regulated financial advice is worth getting.
They stay up. A tool that works costs almost nothing to keep online, and a calculator that is right today is still right in three years. What stops is my adding to it. If one ever does have to come down, the email list gets told before it happens.
Because charging for them would answer a different question from the one I am asking. A paywall measures who will pay for a calculator, which is close to nobody, and tells me nothing about whether the underlying decision is one people actually need help with. Free, useful, and counted is a much better instrument.
There are no adverts and nothing is sold. Nothing about you is sold either — there is a page on exactly what gets counted, and the short version is: no cookies, no identifier, and nothing you type into a calculator is ever stored.
Two things at the bottom of every tool, both of which genuinely work:
If a number looks wrong to you, please say so in that box. Money decisions are personal in ways a calculator can miss, and “this told me X and my actual mortgage doesn’t work like that” is the most valuable sentence anyone can send me.
Haydn, in the UK. Built in evenings. If you want to reach me, the box on any tool page comes straight to me, and replying to any email on the list does too.