# Betting exchange commission calculator > Free betting exchange commission calculator: net profit on back and lay bets after commission at Betfair or Smarkets, and whether an exchange price beats a bookmaker. - URL: https://safebet.ai/uk/prediction-markets/commission-calculator/ - Markdown version: https://safebet.ai/uk/prediction-markets/commission-calculator/index.html.md - Last updated: 2026-10-22 - Publisher: SafeBet.ai - Editorial policy and advertiser disclosure: https://safebet.ai/editorial-policy/ UK · Prediction markets · Free tool Enter the odds, your stake and the exchange’s commission to see what a back or lay bet really pays, the odds after commission, and whether the exchange beats a bookmaker’s price. By [SafeBet.ai Research Team](https://safebet.ai/editorial-policy/) Updated October 22, 2026 [2 sources](https://safebet.ai/uk/prediction-markets/commission-calculator/#sources) ## Commission at UK exchanges The standard commission each exchange publishes, and what a winning £100 back bet at odds of 3.00 (2/1) returns after it. | Exchange | Commission | What applies | £100 at 2/1 returns | | ------------------------------------------------------------------------------------- | ---------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------- | | [Smarkets](https://safebet.ai/uk/prediction-markets/smarkets-review/) | 2.0% | Standard tier: 2% on net profits per market. A 1% Pro tier applies above 1,500 bets or £1m staked in a month, and a 3% Select tier to the few customers with more than £25,000 of net profit over 12 months. | £296.00 | | [Betfair Exchange](https://safebet.ai/uk/prediction-markets/betfair-exchange-review/) | 2.0% | Basic package of My Betfair Rewards: 2% of net winnings per market, the rate in Betfair’s own worked example; other packages aren’t published. Accounts with more than £25,000 of gross profit over 52 active weeks can also pay an Expert Fee. | £296.00 | | A bookmaker at the same odds | — | No commission: the bookmaker’s margin is built into its odds instead. | £300.00 | ## How the calculator works On a betting exchange you bet against other users. You can **back** an outcome, betting that it happens, or **lay** it, betting that it doesn’t, by accepting another user’s back bet. The exchange doesn’t build a margin into the odds; it takes a commission on your net winnings in each market instead. For a back bet, your net profit is stake × (odds − 1) × (1 − commission), so a 2% commission turns odds of 3.00 into an effective 2.96. For a lay bet, you risk the liability, stake × (odds − 1), to win the backer’s stake, less commission. Enter a bookmaker’s odds on the same outcome to see which pays more, and the exchange odds you’d need to beat the bookmaker after commission. Bookmaker margins can be worked out with our [bookmaker margin calculator](https://safebet.ai/uk/sports-betting/margin-calculator/). [**Compare the 3 best betting exchanges in the UK** Ranked on regulation, fees, features and payouts · Smarkets, Betfair Exchange, Matchbook and more See the ranking](https://safebet.ai/uk/prediction-markets/) ## Frequently asked questions ### How is betting exchange commission calculated? As a percentage of your net winnings in a market: if a £100 back bet at 3.00 wins, the £200 profit at 2% commission costs £4, leaving £196. If you lose the market overall, you pay no commission on it. ### Is an exchange cheaper than a bookmaker? Often, because the exchange takes commission instead of building a margin into its odds, but not always: compare the exchange price after commission with the bookmaker’s odds. The calculator shows the exchange odds you need to beat a bookmaker. ### What is a lay bet? A bet that an outcome won’t happen. You accept another user’s back bet: if the outcome doesn’t happen you win their stake, less commission; if it does, you pay out their winnings, your liability. ### Do exchanges charge extra fees? Some charge their most profitable customers more. Smarkets applies a 3% Select tier to customers with more than £25,000 of net profit over 12 months, and Betfair can charge an Expert Fee to accounts with more than £25,000 of gross profit over 52 active weeks. ## Keep reading [Methodology · 4 min **How we rank betting exchanges and prediction markets in the UK** We only rank betting exchanges licensed by the Gambling Commission, the legal way to trade on events against other people in Great Britain; Polymarket and Kalshi, which block UK users, are never ranked. Each exchange is scored from 0 to 10 on six weighted criteria, licensing and safety, markets and features, commission and fees, liquidity, deposits and withdrawals, and app and experience, and the ranking follows the overall scores. We don't list or score bonuses. Read](https://safebet.ai/uk/prediction-markets/how-we-rank/) ## Sources We verify facts against primary sources (regulators, court records, operators’ own terms) wherever possible. 1. [Smarkets commission FAQ](https://help.smarkets.com/hc/en-gb/articles/212654665-Smarkets-commission-FAQ) — Smarkets , updated 2025-02-17 2. [Betfair charges](https://web.archive.org/web/20251011010622/https://www.betfair.com/aboutUs/Betfair.Charges/) — Betfair , Internet Archive capture of 2025-10-11 Researched and written by [SafeBet.ai Research Team](https://safebet.ai/editorial-policy/) · Betting analysts & data scientists The team behind SafeBet.ai’s AI sports picks: data analysts, AI engineers and sports bettors based in Maastricht. Since 2021 our models have analyzed 30,088 matches. We review betting, casino and prediction-market platforms against a published methodology and cite official sources for every fact. [Editorial policy](https://safebet.ai/editorial-policy/) [How we rank](https://safebet.ai/uk/prediction-markets/how-we-rank/) [About SafeBet.ai](https://safebet.ai/about/) [Report an error](https://safebet.ai/support/) 18+ Betting on elections and other events is legal in Great Britain only with operators licensed by the Gambling Commission, such as licensed betting exchanges, for adults 18+. Polymarket and Kalshi don’t accept UK users. Only play with money you can afford to lose. Gambling problem? Call [0808 8020 133](tel:+448088020133) (National Gambling Helpline, free and confidential, 24/7) or read our [responsible gambling guide](https://safebet.ai/uk/guides/gambling-help-uk/). Top 3 betting exchanges · UK 1. [1 **Smarkets** Best overall 8.7](https://safebet.ai/uk/prediction-markets/smarkets-review/) 2. [2 **Betfair Exchange** Biggest exchange 8.6](https://safebet.ai/uk/prediction-markets/betfair-exchange-review/) 3. [3 **Matchbook** Prediction-style markets 7.6](https://safebet.ai/uk/prediction-markets/matchbook-review/) [Full ranking](https://safebet.ai/uk/prediction-markets/) Free betting exchange tools - [Betting exchange commission calculator (UK)](https://safebet.ai/uk/prediction-markets/commission-calculator/) Prediction markets guides - [How we rank betting exchanges](https://safebet.ai/uk/prediction-markets/how-we-rank/)