A winning back bet of 10 at decimal odds of 3.0 produces a gross return of 30. Apply a hypothetical 5% commission to its profit and 29 remains. The accepted price can be correct while the amount credited is smaller than the gross return.
Betting exchange commission needs two pieces of information: the rate and the amount it applies to. Some models use a customer's positive net result across one market. Other account tiers charge individual bets. A percentage without its calculation base cannot explain the settlement.
This article uses invented amounts for the arithmetic and named provider documents for the rules. The illustrative 5% and 2% rates are not quoted Betfair tariffs or promises about anyone's account.
A return of 30 can finish at 29
Suppose that 10-unit winning back bet is the only position in its market and there are no other charges. A back bet pays when the selected outcome happens. Decimal odds include the returned stake, so 30 is the gross return and 20 is the profit before commission.
| Line | Amount | Calculation |
|---|---|---|
| Stake | 10.00 | The amount committed to this back bet |
| Gross return | 30.00 | 10 × 3.0, including the stake |
| Gross profit | 20.00 | 30 minus 10 |
| Hypothetical commission | 1.00 | 5% of 20, not 5% of 30 |
| Return after this commission | 29.00 | 30 minus 1 |
| Profit after this commission | 19.00 | 29 minus the original 10 |
The same result can be expressed as an effective return multiple of 2.9: 1 + (3.0 − 1) × (1 − 0.05). That is arithmetic for this winning scenario, not a replacement for the matched odds on the ticket. Another position in the market or an additional charge would change the calculation.
Our guide to accepted sportsbook odds examines price changes and settlement exceptions. Exchange commission is a separate deduction question; a smaller credit does not, by itself, show that an accepted price was altered.
Which results share the commission line?
Betfair Australia's FAQ describes commission on net winnings at market level, rather than transaction level. Its explanation belongs to the Australian exchange service, not every Betfair product or country.
Consider a different invented market with one position making a 25-unit profit and another losing 10 units. Under a model that nets those results first, the commission base is 15. A hypothetical 2% market commission is 0.30, leaving 14.70 in net profit. The total stakes have not been supplied, so 14.70 is profit, not a gross return.
If those results belong to two separate markets, they cannot automatically be combined into one commission base. Under the same illustrative positive-market-only model, the 25-unit winning market generates a 0.50 charge. The separate 10-unit loss leaves an overall profit of 14.50 after that charge. This is a conditional example, not a statement that every losing position is free of fees.
The distinction between an exchange and a sportsbook is covered in our comparison of betting and contract-market products. The fee question is narrower: which settled positions does this calculation group together?
A smaller percentage, a different bill
Smarkets' English-language terms, version 4.14, last modified 14 August 2026, specify a default 2% rate on net winnings in each market. Those are provider terms, distinct from the hypothetical rates above.
The same document describes Pro Tier commission of 1% on winnings or losses per bet and Select Tier commission of 3% on winnings or losses per bet. Account eligibility and tier changes are also governed by those terms. These are not simply lower or higher percentages applied to an unchanged denominator.
The provider's commission FAQ demonstrates the difference. Its Pro Tier example has a winning back bet earning £30 and a losing lay bet losing £20 in the same market. Commission of £0.30 on the winning bet and £0.20 on the losing bet leaves £9.50 overall profit. The fee applies to both results before they are combined.
A description such as "commission only on winnings" therefore needs the product and tier beside it. It would not accurately describe the Pro and Select mechanisms in these Smarkets documents. This comparison explains charging bases, not which account tier anyone should choose.
The fee schedule has a place and a clock
Betfair Australia's Commissions and Charges page says its Market Base Rate depends on the market and that commission is removed when the market settles. It also identifies premium, transaction and turnover charges that some customers may encounter. The single-charge examples here do not model those additional charges.
Smarkets clause 3.8 says commission is calculated and charged at market settlement using the customer's commission at that time, rather than at placement. A rate remembered from an earlier bet is therefore insufficient evidence for that product's settled charge.
The Smarkets document also restricts registration by country. An English help page is not proof that an exchange can serve a reader everywhere. Use the applicable country, product, market and account terms; neither provider's example establishes a worldwide fee.
All amounts in our invented examples are units of a currency with two decimal places, and the calculations terminate exactly at that precision. They do not establish a provider's rounding rule. Smarkets separately describes conversion of odds to percentage prices and possible rounding of stakes or liabilities in clauses 6.12 and 6.13. Keep the matched price and actual settled lines when checking a difference.
For a deduction that does not reconcile, ask for the market identifier, included bets, profit or loss before commission, applicable tier or rate, commission base and charged amount. Separate later charges from that market calculation. Money credited to an exchange account is also different from a bank withdrawal; our withdrawal-timing explainer follows that later process.
A settlement record should let the reader trace the amount credited back to the matched bets and applicable charges. The odds alone cannot supply the missing commission line.
