OK — been on this thing for about four months now and it's basically bookmarked at this point, reckon I'd write something up since a lad on another thread asked me last week. I'm in the UK, generally do football and horses, nothing mad, so take it how you like.
 
How I found it was actually a bit daft — I could never get my head round what an e/w payout would be once you get five places instead of three. I'd just wing it and then be surprised. Now I stick my stake in first, every time, even the boring singles.
 
Their single bet calculator is the bit I open most — type in stake and odds and you get the return straight away, either odds format. There's also the multiples — acca and treble returns, lucky 15s, a yankee, honestly that's where I'd always got it wrong. If you want a look, it's here <a href=https://singlebettingcalculator.uk/bet-calculator/accumulator>acca accumulator</a> and there's no login wall, which I appreciated.
 
The thing that really shifted things for me was the more serious tools. There's an implied probability calculator which shows you the overround, and there's the kelly staking calculator — I stick to fractional kelly as the full version is terrifying. Dutching calculator is handy too if I'm covering two or three runners.
 
Not all sunshine though. Its interface is very functional, let's say — no frills, looks like it was built by someone who cares more about maths than colours. Phone-wise it's fine although the acca grid make you pinch and zoom. Also there's no app, just the site — fine by me but worth saying.
 
So yeah. Doesn't cost anything, not plastered in adverts, does the job. If anyone still works out returns on a calculator app, give it a go — saved me a load of arguments with the bookie.