Guides

The arithmetic behind the tools on this site, explained plainly. No tips, no promotions, and no claims about what you might win.

What is bookmaker hold, and what does it actually cost you?

The margin built into every price, how to calculate it in two lines, and what 5% versus 1% is worth on $1,000 of turnover.

4 min read

Closing line value: the number that measures skill instead of luck

Why professionals track CLV rather than win rate, the formula, and how many bets it takes before yours means anything.

5 min read

How arbitrage betting works — and why most arbs disappear

The arithmetic, the stake split, and the four practical reasons an arb you can see is often one you cannot take.

5 min read

No-vig fair odds: working out what a price should be

Strip the margin out of a market to get its honest estimate of the true chance — the benchmark that tells you whether any other price is value.

5 min read

The Kelly criterion: how much to stake once you've found an edge

The bet-sizing formula worked through with real numbers, and why quarter Kelly is the sensible compromise.

5 min read

Middles: betting both sides at different lines

How to price a middle from actual results, and why most of the hundred on any board are not worth taking.

5 min read

Turning a bonus bet into cash you can withdraw

A bonus bet is not money and its stake is not returned. Hedging converts about 70% of face value into real cash.

4 min read