Tools
Exchange commission
A bookmaker is a shop. An exchange is a room full of other punters. The house does not take the other side of your 5/2. It takes a cut when you leave the room richer than you went in. That cut is commission. It is not VAT on the stake, and on the ordinary customer rates it is not a gym membership billed every Monday.
Checked against the companies’ published help pages and terms in September 2026. They change the numbers. The rate on your account at settlement is the one that bites.
One market, one sum
You can back, lay, trade out and make a mess in a single market. At the off the exchange nets the lot. Standard consumer commission is a percentage of that net profit. A net loss: nothing. A £10 losing lay and a £12 winning back in the same market is £2 profit. Commission is taken on the £2, not on both tickets like a souvenir shop.
The back-and-lay sheet uses that consumer rule. It will not pretend to be Smarkets Pro, which also taxes the bets you lose.
Betfair
Their own help page is blunt. Commission only on net winnings on a market. Losing bets do not pay. The formula they print is Commission = Net Winnings × Market Base Rate × (100% − Discount Rate). The base rate is set by where you live. Betfair’s worked examples use 5%. If you opt into My Betfair Rewards you pick a package — commonly 2%, 5% or 8% — instead of the old points discount that nobody could explain in a pub.
Still per market, at settlement. From 2025 an Expert Fee sits on top for a handful of accounts that print money over a rolling 52 weeks. That is not the 5% most people pay. It is the bill for being too good at the room. Source: Betfair help, “What is Commission and how is it calculated?”
BetDAQ
The official charges page is the rare thing on an exchange: a flat number. 2% on net market winnings if you live in the UK, Ireland, Gibraltar or Jersey. 5% if you live somewhere they have decided is elsewhere. A net loss in the market: nothing. They can mark an Enhanced Commission on a sport; it has to be written on the market, not sprung in the small print after the photo. Commercial and API accounts can be put on other rates with notice. The “commission points” they hand out for activity do not change the 2%. Source: BETDAQ commission charges.
Matchbook
The rate they publish for ordinary customers is 2% of net winnings in the UK, Ireland, the Channel Islands and the Isle of Man; 4% elsewhere. Losing bets do not pay. Matchbook Zero is a different counter — limited, advertised at 0% commission and 0% margin, not the main book. Promotional 0% weeks exist and then they end, which is the entire personality of a promotion. Their terms page did not give up a clean clause in this check. Believe the rate printed on the account.
Smarkets
Terms clause 3.1 is the one that matches everyone else: 2% of net winnings in each market. Per market, not per bet. Nothing on a losing market. Default accounts are capped at 1,500 bets or £1m staked in a calendar month, whichever you hit first. That is the only monthly number in this piece, and it is a volume cap, not a subscription.
Then the T&Cs grow teeth. Pro (3.3) is 1% on every matched bet, win or lose. A £10 back that gets beaten costs £10.10. You opt in for at least three calendar months. Select (3.5) is 3% on every bet, win or lose, if you have made more than £25,000 net with them over the previous 12 calendar months. Commission is taken at settlement on the rate then in force (3.8). Sources: Smarkets T&Cs §3 and their commission FAQ.
Type 2 or 5 into the sheet if you are an ordinary customer. Do not type 1 or 3 and call it Pro. Pro charges the losing side. The sheet does not.