Bookmaker Margins Explained: What UK Betting Sites Really Charge You
Every price a bookmaker quotes carries a charge built into it. This is the Margin Study, August 2026. The average bookmaker margin measured at 18 UK betting sites across 5 competitions, with the sample size and the capture window printed on every row. Groceries have to show a unit price so you can compare on a common base. Betting odds do not. So we have printed one.
- Book sum
- S = Σ(1 / oi) every outcome in the market
- Margin
- M = (S − 1) × 100 the overround
- Payout
- P = 100 / S share of stake returned
- Your cost
- C = 100 − P per £100 staked — the unit price
The register: average bookmaker margins across five UK competitions
Ordered by measured cost across our August 2026 sample, keenest first. Not by bonus, and not by whether we have a commercial relationship. how this was measured and who pays us.
| # | Bookmaker | Margin / unit price | Premium over keenest | Sample |
|---|---|---|---|---|
| 01 | Betfred keenest | 6.02% £5.67 per £100 staked | — | 58 markets 7 August 2026 |
| 02 | Coral | 6.03% £5.69 per £100 staked | +£0.02 | 58 markets 7 August 2026 |
| 03 | Ladbrokes | 6.71% £6.29 per £100 staked | +£0.62 | 58 markets 7 August 2026 |
| 04 | Betfair Sportsbook | 6.86% £6.42 per £100 staked | +£0.75 | 40 markets 7 August 2026 |
| 05 | Unibet | 7.55% £7.02 per £100 staked | +£1.35 | 57 markets 7 August 2026 |
| 06 | Casumo | 7.90% £7.33 per £100 staked | +£1.66 | 58 markets 7 August 2026 |
| 07 | Grosvenor | 7.90% £7.33 per £100 staked | +£1.66 | 58 markets 7 August 2026 |
| 08 | William Hill | 7.96% £7.37 per £100 staked | +£1.70 | 57 markets 7 August 2026 |
| 09 | 888sport | 8.18% £7.56 per £100 staked | +£1.89 | 57 markets 7 August 2026 |
| 10 | Paddy Power | 8.56% £7.88 per £100 staked | +£2.21 | 58 markets 7 August 2026 |
| 11 | BetVictor | 8.72% £8.02 per £100 staked | +£2.35 | 58 markets 7 August 2026 |
| 12 | Betano | 8.72% £8.02 per £100 staked | +£2.35 | 58 markets 7 August 2026 |
| 13 | Betway | 8.72% £8.02 per £100 staked | +£2.35 | 58 markets 7 August 2026 |
| 14 | Sky Bet | 9.11% £8.35 per £100 staked | +£2.68 | 58 markets 7 August 2026 |
| 15 | LeoVegas | 9.40% £8.59 per £100 staked | +£2.92 | 58 markets 7 August 2026 |
| 16 | LiveScore Bet | 9.88% £8.99 per £100 staked | +£3.32 | 58 markets 7 August 2026 |
| 17 | Virgin Bet | 9.88% £8.99 per £100 staked | +£3.32 | 58 markets 7 August 2026 |
| 18 | BoyleSports | 11.83% £10.58 per £100 staked | +£4.91 | 57 markets 7 August 2026 |
Betting exchanges — measured separately, and not comparable
| Smarkets | Premier League 2.80% · Championship 4.92% · League One 13.69% · League Two 14.69% · ATP Canadian Open 3.32% | 58 markets |
| Betfair | Premier League 1.58% · Championship 5.75% · League One 24.81% · League Two 49.35% · ATP Canadian Open 0.84% | 52 markets |
An exchange charges commission on net winnings. It does not set an overround, so its book sum is a by-product of the order book rather than a price anyone chose. Our own data shows it plainly: Betfair’s implied figure runs at 1.58% on the Premier League and 49.35% in League Two — not because it charges more in League Two, but because the book is thin there. 6 markets quoted every outcome below 1.10 and were excluded as unpriced, under the same rule applied to every operator here. Ranking exchanges against bookmakers on one scale would be measuring liquidity and calling it price.
Not sampled: The Hundred — 3 events, below the 8-event floor. Shown as not sampled rather than reported on a thin sample.
The same figures, drawn
The table ranks; the chart shows how far apart the ranks actually are.
The average bookmaker margin in this sample, explained
What the figures above mean, where they come from, and the one distinction most comparisons get wrong.
Across the 18 operators in this study the average bookmaker margin was 8.33%, which works out at £7.67 taken from every £100 staked. The more useful number is the spread: Betfred priced at 6.02% and BoyleSports at 11.83%, a difference of £4.91 per £100. Two UK bookmakers taking the same bet on the same match are not selling the same product at the same price, and nothing on either website says so.
The bookmaker margin formula
The bookmaker margin formula begins with the book sum. Convert every price in a market to its implied probability by dividing one by the decimal odds, then add them up. A market priced without a charge would total exactly 1. Real markets total more, and the surplus is the margin. If you want to know how to calculate bookmaker margin on any market in front of you, that is the whole method: add the reciprocals, subtract one.
On a two-way market priced 1.90 and 1.90 the reciprocals are 0.5263 each, the book sum is 1.0526, and the margin is 5.26%. On the three-way football market 2.10 / 3.50 / 3.60 the book sum is 1.0397 and the margin is 3.97%. The same bookmaker margin formula applies whatever the number of outcomes, which is why a three-way football market and a two-way tennis match can sit in one table without adjustment. Every figure in the register above was produced this way and no other way.
Our odds calculator runs the same arithmetic on any prices you paste into it, but knowing how to calculate bookmaker margin by hand is what makes this register checkable rather than something you have to take on trust.
Margin and cost are different numbers
This is where most published comparisons go wrong. The margin is measured against the fair book; your cost is measured against your stake. A book quoted at a 5% margin does not take £5 from every £100 you stake — it takes £4.76. The relationship is C = M / (1 + M), and the gap widens as the margin grows: BoyleSports’s 11.83% margin is a cost of £10.58, a difference of 1.25 percentage points. Quote one figure and label it the other and you are wrong by about that much.
Both numbers are printed on every row above, which is what the unit-price toggle switches between. Across several legs the distinction matters more, not less, because the charge compounds — that is explained separately, since a six-fold surrenders roughly a quarter of its fair value before a ball is kicked.
What a margin does not tell you
A margin is a charge on a market, not a forecast of anyone’s results. It describes what a price costs before any event has taken place. How much profit do bookies make in practice is a different question, because the bookmaker profit margin realised over a season depends on how balanced the book was and how results fell, not only on how the market was priced.
So treat the two as separate things. How much profit do bookies make is an accounting question about an operator’s year; the bookmaker profit margin built into a single market is a published price you can check yourself in about a minute. This register only measures the second, because it is the part a customer can see before staking anything. How we sample it, and who pays us, is explained in full on the method page.
Two limits worth stating plainly. These are averages across 5 competitions in a single capture window, not live prices, and an individual market can sit well above or below an operator’s average. And a single average bookmaker margin for the whole UK market would hide the spread that matters. A keen average describes price, and price is one property of a betting account among many.
What a bookmaker margin costs you per £100
The register prices the market. This prices your habit — the same margin, applied to how you actually bet. A shelf label states the unit price before you buy; a receipt totals what you actually paid.
Bookmaker margins explained: questions about the method
The full method, the basket definition and our commercial position are on the method page. The short answers:
Is the margin the same as what it costs me?
No, and the difference is why both figures are printed on every row. A book quoted at a 5% margin costs £4.76 per £100 staked, not £5.00. The margin is measured against the fair book; the cost is measured against your stake. The relationship is C = M / (1 + M). Most sites publish one figure and label it the other.
Why does an accumulator lose so much more?
Because the margin compounds on every leg. Retained fair value is (1 + M) to the power of minus n, so at a 5% margin a four-fold retains 82.27% and a six-fold retains 74.62%. The bet shape, not the bookmaker, is doing most of the work.
How can a bookmaker you link to rank badly?
Because the order is set by the measurement, not by the commercial relationship. We measure every bookmaker we can sample and publish the order that comes out. We can only link the ones we have an arrangement with, which is a different thing and is stated on the method page, along with the list of bookmakers we measure but do not review.
How current is this study?
It is a dated study, not a live feed. Every figure here was captured on 7 August 2026 and every row carries the number of markets behind it. Prices move constantly; these are ours, from that window, and they are not updated in the background.
What is an average bookmaker margin in the UK?
Across our sample the 18 bookmakers measured ran from 6.02% to 11.83%. Any single figure quoted as "the" UK average hides that spread, which is worth £4.91 per £100 staked between the keenest and the dearest price in this sample.