Betting calculators

Nine calculators on the same exact formulas as our guides. They run in your browser and send nothing to us.

Decimal, fractional and American odds, and the probability they imply.

The overround of a market, the bookmaker's margin and the odds without it.

Payout, chance to win and the compounded margin of an accumulator.

The stake that grows a bankroll fastest when your edge is real, and fractional Kelly.

What a bet is worth per unit, and the break-even probability of any odds.

How much to bet on the other side to lock in a result.

Stakes on two or three outcomes for the same return whatever happens.

Returns of the win and place parts under any place terms.

Lay stake, liability and the result either way, with exchange commission.

Updated: 2026-09-26