Odds boosts and betting promotions: what they are worth

Odds boosts and betting promotions change what a bet costs or pays: an odds boost or profit boost raises the payout on a winning bet, a bet credit lets you stake without using your balance, and a deposit match adds bonus funds that carry rollover. Each has a value you can calculate, and it is usually smaller than the headline. A boost is worth something only if the new price beats the fair price.

The two numbers that matter are the bookmaker's margin, which is built into every price, and whether your stake comes back when you win. This guide works through each common offer.

Bet credits

What many bookmakers advertise as a free bet is a bet credit: a stake you can place without using your own balance. Two terms make it worth less than its face value.

• The stake is not returned. A £10 bet credit at 3.00 (2/1) that wins pays £20, not £30. You keep the winnings only.
• A qualifying bet is often required. You may need to bet your own money first. UK advertising guidance from CAP says marketers should not describe an offer as free if the customer must risk their own money to qualify, and that a qualifying bet must be stated clearly.

What a £10 bet credit is worth

The expected value of a bet credit is the winnings it pays times the chance of winning. At decimal odds O, the winnings are £10 × (O - 1). If the price were fair, the chance of winning would be 1 ÷ O. Real prices include a margin, so here we assume an illustrative 5% overround and a true chance of 1 ÷ (O × 1.05). The figures are our calculation.

At longer odds the missing stake is a smaller part of the payout, so more of the credit's value survives. The catch is variance: at 10.00 you win about one time in ten and the credit is gone the other nine.

If a qualifying £10 bet is needed, it has its own expected cost: at a 5% margin, £10 × (1 - 1/1.05) = about 48p. That is small next to the credit, but the bigger risk is behaviour: a promotion that gets you betting more often than you planned costs far more than its maths suggests.

Use the converter to translate fractional or American odds before you do the sums:

Odds boosts

An odds boost raises the price on a selection, usually for a limited stake. Its value depends on the fair price, not the old price.

Example (illustrative). A selection is boosted from 3.00 to 3.50, and its true chance makes the fair price 3.15. A £10 bet has an expected return of £10 × 3.50 ÷ 3.15 = £11.11, so an expected profit of about £1.11. If the fair price were 3.60, the same boost would still lose money on average. A boost on a bet builder or a long parlay starts from a price with a larger margin built in, so the boosted price can still be below fair. Our parlays and bet builders guide explains why.

Profit boosts

A profit boost adds a percentage to your winnings, for example 25%. On a £10 bet at 3.00, normal profit is £20; boosted, it is £25, which is the same as betting at 3.50. Work out the effective price this way and compare it with the fair price, exactly as for an odds boost. Check the maximum stake and any cap on the extra winnings.

Price promises

A price promise on horse racing means that if you take a fixed price and the starting price turns out bigger, you are paid at the starting price. On the bet it covers, it can only help you. Read the terms for which races qualify, whether it is limited to certain customers, and whether it applies to each-way bets. Our each-way and horse racing guide explains starting prices.

Deposit matches and rollover

A deposit match adds bonus funds in proportion to your deposit. The cost sits in the rollover (wagering): the amount you must bet before you can withdraw. Every pound of turnover loses the margin on average.

Example (illustrative, our calculation). A £50 bonus with 5x rollover means £250 of bets. At a 5% overround, the expected cost is £250 × (1 - 1/1.05) = about £11.90. At 10x, it is £500 of bets and about £23.81. Minimum-odds rules and time limits push that cost up or make the bonus hard to clear.

UK rules: wagering cap and no mixed products

Since 19 January 2026, the UK Gambling Commission's social responsibility code 5.1.1 has said that licensees must not "apply wagering requirements, which requires a customer to play through bonus funds, over a maximum of 10 times". The code applies to "all licences (including ancillary remote licences), except gaming machine technical and gambling software licences". It does not name betting or any other sector separately; on our reading, because betting licences are not among the exceptions, a betting bonus with a play-through requirement falls under the same limit. Read more in our guide to the UK 10x wagering cap.

The same code says licensees must not include more than one type of gambling product (betting, casino, bingo and lottery) within an incentive. The Commission's announcement gives the example of a promotion that requires both betting and playing slots. In practice, a betting offer cannot also require casino play, and the other way round.

Outside Great Britain, promotion rules differ by market, so check the rules where you live.

Mistakes to avoid

• Valuing a bet credit at face value. £10 in credits is worth well under £10.
• Judging a boost against the old price. Compare with the fair price.
• Ignoring rollover. Each pound of turnover costs the margin.
• Betting to use up a promotion. If you would not have placed the bet anyway, the offer has cost you money. See wagering requirements explained.

Where to bet

See our UK betting site listings, New Jersey sportsbook listings and the sports betting markets hub. For margins and fair prices, read betting margins and value and how to read betting odds.