Betfair commission is the share of your net winnings that the exchange keeps from each market you finish ahead in. It adds up every bet you hold in that market, works out what you made or lost on the actual result, and charges its rate only on a net win. At an illustrative 8%, a market you finish $100 ahead in leaves you $92, and a market you finish behind in costs no commission at all.
The exchange sets its commission, and any extra charges on some winning customers, in its own terms and can change them. So every figure below uses a rate labelled as illustrative: swap in the one shown in your own account.
How commission on net winnings is worked out
Three steps settle every market:
- Price each of your bets in the market on the actual result. A winning back makes stake x (odds - 1), a winning lay makes its lay stake, and a losing bet costs its stake or its liability.
- Add them up. The total is your net result in that market.
- If the total is above zero, commission = net winnings x rate. At zero or below, there is no commission.
Commission comes off profit, never off the stake or the whole return. With illustrative prices and an illustrative 8% rate:
| Your position in one market | Net result | Commission at 8% | You keep |
|---|---|---|---|
| $20 back at $6.00, and the runner wins | 20 x 5.00 = +$100.00 | 100 x 0.08 = $8.00 | +$92.00, a $112 return with the stake |
| $40 lay at $3.50, and the runner loses | +$40.00 | 40 x 0.08 = $3.20 | +$36.80 |
| $40 lay at $3.50, and the runner wins | 40 x 2.50 = -$100.00 | None | -$100.00 |
| $20 back at $6.00, and the runner loses | -$20.00 | None | -$20.00 |
Charging 8% on the $120 return in the first row would take $9.60, not $8. A lay's $100 liability never attracts commission either: on a lay, the rate comes only out of what the lay wins.
Per market, not per bet: a worked race
Netting matters most when you hold several bets in one market. With illustrative prices and the same 8% rate, you hold three bets in one race's win market:
- a $40 back of Runner 3 at $6.00
- a $60 lay of Runner 1 at $2.50, a liability of 60 x 1.50 = $90
- a $10 back of Runner 7 at $15.00
| Result | Back Runner 3 | Lay Runner 1 | Back Runner 7 | Net in the market | Kept, commission on the net | Kept if charged bet by bet |
|---|---|---|---|---|---|---|
| Runner 1 wins | -$40 | -$90 | -$10 | -$140 | -$140.00 | -$140.00 |
| Runner 3 wins | +$200 | +$60 | -$10 | +$250 | 250 - 20.00 = +$230.00 | 250 - 20.80 = +$229.20 |
| Runner 7 wins | -$40 | +$60 | +$140 | +$160 | 160 - 12.80 = +$147.20 | 160 - 16.00 = +$144.00 |
| Any other runner | -$40 | +$60 | -$10 | +$10 | 10 - 0.80 = +$9.20 | 10 - 4.80 = +$5.20 |
On the net, the bets that lose shrink the amount the rate is charged on. In the last row the lay wins $60 while the two backs lose $50 between them, so commission falls on $10, not on $60. Bet by bet, the Runner 3 row would pay 0.08 x (200 + 60) = $20.80 instead of 0.08 x 250 = $20.00. The -$140 row is the most this race can cost you, and it is the amount reserved from your balance until the race settles, as the exposure glossary entry works through.
Each market is charged on its own
Netting stops at the edge of a market, so a loss in one market does nothing for the commission on a win in another. With illustrative figures at 8%, finishing Race 2 $100 ahead and Race 5 $100 behind means $8.00 of commission in Race 2 and none in Race 5. The day ends 92 - 100 = -$8.00, not level.
A race's win market and its place market are separate markets too. With illustrative prices, back Runner 4 to win for $20 at $8.00 and to place for $20 at $2.50:
| Runner 4 finishes | Win market | Place market | Total after 8% commission |
|---|---|---|---|
| First | +$140, keeps 140 x 0.92 = $128.80 | +$30, keeps $27.60 | +$156.40 |
| Second or third | -$20 | +$30, keeps 30 x 0.92 = $27.60 | +$7.60 |
| Unplaced | -$20 | -$20 | -$40.00 |
The second row is the one to notice. Across the two markets you are $10 ahead, but the place market pays commission on its own $30 win, $2.40, where one combined market would have charged $0.80. Bets you think of as one position can pay more commission than their combined result suggests once they span two markets. Exchange place markets covers the place side.
Commission in back and lay maths
Commission changes the price you are really getting on both sides of the exchange.
Backing: the effective back price
effective back price = 1 + (back price - 1) x (1 - rate)
With illustrative prices and an 8% rate, an exchange back price of $5.00 pays like 1 + 4.00 x 0.92 = $4.68. A bookmaker offering $4.75 for the same bet beats it: on $50 the bookmaker's win is 50 x 3.75 = $187.50, against 50 x 4.00 x 0.92 = $184 on the exchange. With the rate as an input:
| Exchange back price | At 5% | At 8% | At 10% | Share of the price lost at 8% |
|---|---|---|---|---|
| $2.60 | $2.52 | $2.47 | $2.44 | 4.9% |
| $5.00 | $4.80 | $4.68 | $4.60 | 6.4% |
| $12.00 | $11.45 | $11.12 | $10.90 | 7.3% |
The share lost is rate x (price - 1) / price, so commission takes a bigger slice of a long price than of a short one: 0.08 x 11.00 / 12.00 = 7.3% at $12.00, against 0.08 x 1.60 / 2.60 = 4.9% at $2.60.
Laying: the effective lay price
A lay risks its whole liability but keeps only lay stake x (1 - rate) when it wins, so commission makes every lay dearer:
effective lay price = 1 + (lay price - 1) / (1 - rate)
Laying at an illustrative $3.20 with an 8% rate risks $2.20 to keep $0.92 for each dollar of lay stake, the same trade as a commission-free lay at 1 + 2.20 / 0.92 = $3.39. The lay pays its way on average only if the runner's fair price is longer than about $3.39, a chance below 1 / 3.39 = 29.5%. Exchange prices as fair odds covers where a fair price can come from, and the lay bet calculator runs the same sums at your own rate.
Commission in a hedge's lay stake
To leave the same result either way, the rate goes into the denominator of the lay stake:
lay stake = back stake x back price / (lay price - rate)
Example: illustrative prices. You backed Runner 2 with Bookmaker A for $20 at $3.90, and it is now $3.20 to lay on the exchange. At an 8% rate the lay stake is 20 x 3.90 / (3.20 - 0.08) = 78 / 3.12 = $25.00, a liability of 25 x 2.20 = $55.00. If Runner 2 wins: 20 x 2.90 - 55 = +$3.00. If it loses: 25 x 0.92 - 20 = +$3.00.
The lay is your only bet in that exchange market, so its commission falls on its own win: 25 x 0.08 = $2.00, two thirds of the $3.00 the hedge keeps. Left out of the formula, the rate would shrink the lay to 78 / 3.20 = $24.38 and the two results would no longer match, as the mistakes table shows.
Hedging bets covers when a hedge is worth its cost, and the hedge calculator sizes one at your own rate.
Risk: Betting involves risk. A hedge holds only if the lay is matched in full at the price you sized it for, a rate higher than the one in your sums shrinks the result on one side, and there is no guarantee of profit. See responsible gambling for limits and support.
Rates, extra charges and how to check yours
The exchange publishes its commission rates in its own terms. They can differ from one market to another and can change, so take a rate, a threshold or a charge only from the exchange's current terms and your own account, never from an old article or a forum post.
Commission may not be your only cost. An exchange's terms can add a further charge for certain winning customers, and only its current terms say whether one applies to you and how much it takes. If your terms carry one, model it as a second input: with illustrative figures, a month that keeps $640 after commission keeps 640 x (1 - 0.25) = $480 if a further 25% of it goes in charges. Is Betfair trading profitable shows what those costs do across hundreds of trades.
To check the rate actually applied, take any settled market from your account history: rate = commission charged / net winnings in that market. With illustrative figures, a market with $40 of net winnings and $3.20 of commission was charged 3.20 / 40 = 8%. If a figure looks wrong, raise it with the exchange and ask for a dispute reference number.
Exchange commission in Australia
In Australia the commission sits in the exchange's own terms, not on a register: ACMA's register of licensed wagering providers shows who licenses a provider, not what it charges. On the register last updated 7 September 2026, Betfair Pty Ltd's licensing authority is the Northern Territory's wagering regulator, and the company is on the NT Wagering Commission's list of operators (both checked October 2026); is Betfair legal in Australia reads that entry in full.
For an operator the NT licenses, the NT Government's complaints page says to raise a dispute with the operator first, then refer it to the NT Wagering Commission within 60 days of becoming aware of the issue (checked October 2026).
Commission mistakes and what each costs
With the illustrative 8% rate and the examples above:
| Mistake | What it costs | The fix |
|---|---|---|
| Taking commission off the return | On the $20 back at $6.00 you budget $9.60 of commission instead of $8 | Charge the rate on the net profit in the market |
| Comparing a bookmaker price with the raw back price | $5.00 on the exchange looks better than $4.75, yet on $50 it wins $184 against the bookmaker's $187.50 | Compare with the effective back price, $4.68 |
| Leaving the rate out of a hedge | Laying $24.38 at $3.20 against the $20 at $3.90 leaves +$4.36 if Runner 2 wins and +$2.43 if it loses, instead of +$3.00 either way | Put the rate in the denominator: 78 / 3.12 |
| Netting across markets | A $100 win in Race 2 and a $100 loss in Race 5 do not cancel out: the day costs $8 | Treat each market's result on its own |
The working for the hedge row: if Runner 2 wins, 58 - 24.38 x 2.20 = 58 - 53.64 = +$4.36; if it loses, 24.38 x 0.92 - 20 = 22.43 - 20 = +$2.43.
Where B337 fits
B337 places no back or lay bets on the exchange, so every commission sum here applies to bets you place yourself, in your own exchange account. On the Terminal, Betfair's back and lay prices sit beside racing and sports prices from 40+ bookmakers, with flucs and closing lines; apply your own rate to the exchange price before comparing it with a bookmaker's. The Terminal reads prices on a repeating cycle, not tick by tick, so confirm a price on the exchange before you bet.
A free account opens a limited view of the Terminal with live odds; Betfair's prices start at Terminal View, as plans and pricing shows. Laying from the start is in the lay betting hub. Bookmaker names are trade marks of their owners. B337 is not affiliated with them.
For free and confidential support call 1800 858 858 or visit gamblinghelponline.org.au.
Risk: Betting involves risk. Commission comes off every winning market whatever happened in the last one, prices on the Terminal can trail the exchange's own, and there is no guarantee of profit. See responsible gambling for limits and support.