Betting Margins Explained


The ever-expanding world of online betting offers endless opportunity for bettors to handpick the best odds and bets from a wide array of offers.

Many bookmakers will claim to have the best-valued odds, but the burning question every tipster and punter is keeping their minds on is whether they will truly get the best deal for their money.

All of those who want to remain on top of things and always make sure they get the best odds possible need to make sure they understand how betting margins work.

What betting sites and bookies in general will do is adjusting the odds in order to attract bets from as many bettors as they can with a simple aim of securing a profit whatever the outcome may be.

The way they do this is by offering odds that often exceed the statistical probability of a chosen event, making sure they secure what is called a bookmaker’s margin. It is usually represented as the betting over-round or the market percentage with amounts over 100% and it is that difference between the actual value and the marketing value of a particular product – in this specific case a bet.

How do you calculate a betting margin?

If we are to bet on a match between Novak Djokovic and Andy Murray with Djokovic available at the betting odds of 1.65 and Murray standing at 2.35, the betting margin for this particular game will be:

(1/1)*100 + (1/2.35)*100 = 60.6 + 42.55 = 103.15%

This is close to 100%, so punters are getting a good deal, but the bookmaker has put in a 3.15% margin here, so if they have an even book, with the same amount of money placed on each player, their profit is 3.15% of the market.


Best 10 New Bookmakers

£40 SIGN UP HERE

New customers online only, UK & ROI, 18+. Place £10+ qualifying bet at 1/1 (2.0) odds+ (EW: £10 Win + £10 Place). Get £20 Tote Credit, £10 Free Bet + 50 Free Spins (selected game) within 48h. Free bets/Tote Credit expire in 7 days. One per customer. Full T&Cs apply. BeGambleAware.org

£10 SIGN UP HERE

New Customers use code EPL10. Deposit £10 and place a bet of £10 on any Premier League Outrights 2025/26 market at minimum odds of 2.0. Free Bet credited within 24 hours and must be wagered on English Premier League markets only. Full Terms apply. Bangers N'Cash rewards are a separate promotional scheme and must be opted into during the weekly promotional period via the BetWright Rewards Section. 18+ begambleaware.

10 SIGN UP HERE

100% Casino Bonus up to £100 (new players only), £10 min deposit, no max cash out, 40x wagering, £5 max bet with active bonus, eligibility restricted for suspected abuse, cashback unrestricted, Skrill & Neteller excluded, T&Cs apply. Free bet min odds 2.0; free bet value deducted from winnings.

£30 SIGN UP HERE

18+ New customers only. Place a £10+ bet at min odds 1/1 (2.0) within 14 days of sign-up. Get £30 in Free Bets, valid for 7 days on selected bets only. Free stake not returned with winnings. T&Cs apply. BeGambleAware.org

£20 SIGN UP HERE

New customers place your first bet of £10 at minimum odds of 1/1 on any sports market within 7 days of registering. Get £20 in ACCA Free Bets (2x£10 Acca Free bet (2+ selections, pre-match or in-play/live, min odds per leg 2/5 (1.4), max payout £50) . Full terms apply. 18+ begambleaware. Please gamble responsibly.

£40 SIGN UP HERE

New cust. Deposit £10+ in 7 days & bet on sports. Min odds apply. Reward = 4 x £10 Free Bets (2 x £10 Bet Builders & 2 x £10 Sports bet). Valid 7 days. Free bets not valid on e-sports & non UK/IE horse racing. 18+. T&Cs apply. GambleAware.org.

£20 SIGN UP HERE

New UK customers only. Min £20 Single or Acca (2+) at 1.9+ odds, settled within 7 days. Get £20 Free Bet (7-day expiry, max payout £500). Deposit via banking app (Truelayer). Profit Boost: 1/day, claim by 23:59 (UTC+3), max stake £30, 24h valid, max payout £1,000. 18+ BeGambleAware.org.

£10 SIGN UP HERE

*#ad. 18+. Gamble Responsibly. Gambleaware.org. New customers only. £10 in real money. Bets placed on sports at odds of 2.00 ore more to qualify. Bets must be placed 24 hours within of registration. £10 free bets must be wagered on sports. Cashback is cash without restrictions. - Full Terms Apply

£25 SIGN UP HERE

New customers only, 18+, 3 bets of £10+ at odds of evens or greater. Max Free Bet: £25, credited within 24 hours. Free Bet valid for 7 days. T&Cs Apply. BeGambleAware.org.

£25 SIGN UP HERE

New UK Customers Only. Wager £10+ at odds of 2.00+ on any sports market. Receive 50% back on first day’s losses (up to £25) as a Free Bet. Minimum of 3 bets required, with at least 2 bets being 50%+ of the highest stake placed. Even if no loss, place £10+ to get a £5 Free Bet. Free Bets expire in 7 days. Full T&Cs apply.

Read More