OK — have been messing about with this thing for something like a few months now and it's stuck on my phone, so figured I'd chuck my thoughts in since a mate asked me last week. Am based in the UK, generally do football and horses, a fiver here and there, so take it how you like.
The reason I started using it was genuinely a bit daft — I never could figure out what an each way return would be once you get five places instead of three. Basically I'd wing it and then be surprised. Now I type the odds in before I place anything, even a simple single bet.
The single bet calculator is the bit I'm on daily — type in stake and odds and it spits out returns straight away, fractional or decimal, doesn't matter. It also handles the bigger stuff — acca and treble returns, lucky 15 and lucky 63, patents and yankees, honestly that's where I'd always mess it up. If you fancy a poke about, it lives at work out patent bet and it's free with no account nonsense.
One thing that genuinely made a difference were the geekier tools. There's an implied probability converter and it makes obvious the overround, and there's the kelly staking calculator — I run quarter kelly because full kelly is terrifying. Dutching calculator is handy too for when I'm splitting a race.
Not all sunshine though. The layout feels very functional, let's say — zero polish, which honestly I don't mind but some will. On my phone it's usable but the lucky 63 breakdown make you pinch and zoom. Also there's no app, it's browser only — fine by me but worth saying.
Anyway. Free, barely any ads, works. If you even now does the maths on paper, give it a go — it's saved me plenty of arguments with the bookie.