Break-even odds: include commission before judging a bet

For a cash back bet at decimal odds, the winning return includes the original stake. A stake of 10 at 2.50 returns 25 if it wins: 15 profit plus the 10 stake. If it loses, the loss is 10.

This guide assumes an ordinary win/lose cash bet with no void, push, bonus conditions or tax. A free bet whose stake is not returned needs different arithmetic. Exchange lay positions also need their liability included.

Gross expected profit = stake × (estimated win probability × decimal odds − 1).

The probability in this expression must be an estimate you can defend. Reading a bookmaker's price and converting it into a percentage does not independently establish your selection's chance.

Setting expected profit to zero gives:

Break-even probability = 1 ÷ decimal odds.

These are price thresholds, not predictions. A quoted 2.00 does not tell you that the event is truly 50/50. Across a bookmaker's complete market, implied probabilities commonly contain a margin; one selection's reciprocal alone does not remove it.

Suppose commission is charged only on a winning profit at rate c, and this is your only position in the market. The winning profit per unit staked becomes (odds − 1) × (1 − c).

Break-even probability = 1 ÷ [1 + (odds − 1) × (1 − c)].

At 2.00 with an illustrative 5% commission, a winning stake of 10 produces 9.50 net profit. A loss still costs 10. The break-even probability is 1 ÷ 1.95, or about 51.28%.

The 5% is an example, not a current rate for a named exchange. Real commission can depend on market-level net winnings, customer terms and other charges. Multiple positions in one market may therefore need to be assessed together.

Assume, for illustration, a genuinely accurate 51% win probability at 2.00. Before commission, the expected profit per unit staked is 0.51 × 1 − 0.49 × 1 = 0.02.

Under the simple 5% commission assumption, it becomes 0.51 × 0.95 − 0.49 × 1 = −0.0055. A gross expected gain of 2% becomes an expected loss of 0.55%.

Payment fees, exchange-rate costs and any applicable taxes are separate considerations. Do not subtract a fee twice if it is already reflected in the recorded account result. Do not treat a fixed withdrawal fee as a per-bet fee without specifying how you allocate it.

Before deciding that one price is better, check that both selections settle on the same event, period and outcome. A full-time football price and a qualification price are not interchangeable.

1. Confirm the bet type and settlement rules.
2. Confirm the odds actually available for your stake.
3. Include applicable commission using the provider's charging basis.
4. Separate transaction costs from betting returns.
5. Treat uncertainty in your probability estimate as part of the decision.

Our odds converter can check the basic price conversion. It cannot supply the true probability of an event or validate an estimated edge. A narrow numerical advantage is especially sensitive to a small estimation error.