Right — have been messing about with this thing for maybe six months now and it's basically bookmarked at this point, reckon I'd write something up since a lad on another thread asked me the other day. Am UK based, mostly do football and horses, small stakes, so take it how you like.
The reason I started using it was honestly embarrassing — I never could get my head round what an each way payout actually was with 1/5 odds a place. Basically I'd guess and then be surprised. Now I stick my stake in first, every time, even a simple single bet.
The single bet calculator tool is the part I use most — you drop in stake and odds and it spits out returns straight away, either odds format. There's also the fiddly ones — trebles returns, a lucky 15, patents and yankees, which is where most people I know got it wrong. Have a go yourself, it lives at <a>spread betting margin calculator</a> — free, no signup.
The thing that really changed how I bet is the geekier bits. They've got an implied probability calculator that shows how much the bookie's taking, and a kelly criterion calculator — I run quarter kelly since full stakes are terrifying. Dutching calculator is handy too for when I'm covering two or three runners.
Couple of gripes. Its layout looks pretty plain — not much frills, which honestly I don't mind but some will. On mobile it's fine although the acca grid need a bit of scrolling. Also there's no app, it's browser only — slight shame but worth saying.
So yeah. Doesn't cost anything, not plastered in adverts, does what it says. Anyone who honestly works out returns on a calculator app, have a look — it's saved me a fair few "wait, that's it?" moments.