Betting glossary: UK betting terms in plain English

Odds and prices

A price tells you what you will be paid and, read the other way, how likely the bookmaker thinks the outcome is.

• Fractional odds: the traditional British format, for example 5/1, where £1 staked earns £5 profit and the £1 comes back too.
• Decimal odds: the full return for each £1 staked, stake included. 5/1 is 6.0, so £10 returns £60.
• Evens: 1/1, or 2.0 in decimal. A winning £10 bet pays back £20: £10 profit and your £10 stake.
• Odds on and odds against: odds on (such as 1/2) pays less profit than the stake; odds against (such as 3/1) pays more.
• Favourite: the shortest-priced selection in a market, which the bookmaker rates the most likely winner.
• Implied probability: the percentage chance a price represents. 2.0 implies 50% and 4.0 implies 25%. See our implied probability guide.
• Overround (margin): the profit the bookmaker builds into a market. Total the implied probabilities and whatever sits above 100% is the margin. Our bookmaker margin guide shows how to measure it.
• Price boost: a promotion that lengthens a price for a limited time, usually with a reduced maximum stake. Our price boosts guide tests whether they are worth it.

Value betting terms

These are the words you will see most in our value betting guide, which is about judging whether a price is good rather than guessing who wins.

• Value bet: a bet where the price is bigger than the outcome’s real chance justifies. It won’t win every time, but across many similar bets the price works in your favour.
• Expected value (EV): the average result for each £1 staked if the same bet were repeated many times. EV = your probability × decimal odds − 1, so a 50% chance at 2.20 gives +0.10, or 10p per £1. More in our expected value guide.
• Fair odds: prices with the margin removed, so the market’s implied chances total exactly 100%. They are the yardstick you compare real prices against. See the fair odds guide.
• Sharp bookmaker: a firm that accepts big stakes, runs thin margins and reacts quickly to informed money, so its prices are often the best guide to the true chance. In the UK, Betfair Exchange prices are the usual reference point. Read about sharp bookmakers.
• Soft bookmaker: a firm with wider margins that is slower to adjust its prices, so it sometimes offers more than the sharp market’s fair price. Comparing firms is covered in our odds shopping guide.
• Closing line value (CLV): how the price you took compares with the final price before the start. CLV % = odds taken ÷ closing odds − 1, so taking 2.10 on something that closes at 2.00 is +5%. See closing line value.
• Steamer and drifter: a steamer is a selection whose price shortens sharply as money comes in; a drifter is one whose price lengthens. Our steamers and drifters guide explains what the moves mean.

Staking, results and accounts

• Bankroll: the money you have set aside purely for betting, separate from everyday spending. See bankroll management.
• Kelly criterion: a formula that sizes each stake as a share of your bankroll according to your edge and the price. Full Kelly swings hard, so many bettors use a fraction such as a quarter. The Kelly criterion guide has the maths.
• Staking plan: a fixed rule for how much each bet will be, such as a flat £5 or 1% of your bankroll, which stops you upping stakes after a good run or to win money back.
• Yield: profit divided by everything you have staked. £30 profit from £1,000 of bets is a 3% yield. Our betting records guide explains how it differs from ROI.
• Variance: the natural ups and downs that luck brings, which is why short runs of results tell you very little. See how large the swings get in our variance guide.
• Arbitrage: backing every outcome of an event across different bookmakers at prices that should guarantee a profit. Prices move, bets get voided and accounts get limited, so it isn’t risk-free. Compare approaches in value betting vs matched betting.
• Account restrictions: limits a bookmaker applies to a customer, from cutting maximum stakes to closing the account, which UK firms may do for commercial reasons. Our account restrictions guide covers what to expect.

Bet types

• Single: a bet on just one selection.
• Accumulator (acca): a single bet on several selections, all of which must win. The prices multiply, so the potential return grows and so does the risk. See our accumulator margin guide.
• Double and treble: accumulators with two and three selections.
• Bet builder: several selections from one match rolled into one bet, for example a team to win plus a named player to score.
• Each way: two equal bets, one on the win and one on the place, so £5 each way costs £10.
• Lucky 15: four selections covered by 15 bets: four singles, six doubles, four trebles and a four-fold.
• Handicap: a notional head start for the weaker side that evens out a lopsided contest.
• Over/under: a bet on whether a total, such as goals, will finish above or below a stated line. See over 2.5 goals.
• Both teams to score (BTTS): a bet that each team scores at least once. Our BTTS odds guide shows how to price it.
• Correct score: a bet on the exact final score. See the correct score odds guide.
• Outright and ante-post: a bet on the overall winner of a competition, or a race bet struck well ahead of the day. Ante-post stakes are normally not refunded if your pick doesn’t run.

Exchanges and trading

• Back: betting on something to happen, as you would with a bookmaker.
• Lay: betting on something not to happen, taking the bookmaker’s role on an exchange.
• Liability: the amount you would pay out if a lay bet wins for the backer. Laying £10 at 3.00 carries £20 liability.
• Commission: the exchange’s charge on your net winnings in a market, usually a few per cent.
• Matched and unmatched: a bet is matched once someone takes the other side; until then it sits unmatched in the market.
• Trading: backing and laying the same selection at different prices to lock in a result before the event ends. Start with our football trading guide.
• Green up: spreading a trading profit evenly across every outcome. See how to green up.

Horse racing terms

• Starting price (SP): the official price of each runner when the race begins.
• Best odds guaranteed (BOG): if the SP ends up bigger than the price you took, you are paid at the SP.
• Place terms: how many places an each-way bet pays on and what fraction of the win price applies, for example three places at 1/5 of the odds.
• Extra places: a promotion paying each-way bets on more places than the standard terms.
• Non-runner: a horse withdrawn before the off. Singles on it are normally refunded.
• Non-runner no bet (NRNB): an ante-post concession that refunds your stake if your horse doesn’t take part.
• Rule 4 deduction: a reduction in winnings after a late withdrawal, because the remaining runners had a better chance than their prices showed.
• Dead heat: two or more horses finishing exactly level. Your stake is divided between them and each part is paid at full odds.

Offers and free bets

The terms that decide what a welcome offer is really worth. See current offers, or work out a free bet’s value with our free bet value guide.

• Free bet (stake not returned): a bet paid for by the bookmaker. You keep the winnings but not the stake.
• Qualifying bet: the real-money bet you place to trigger a sign-up offer.
• Minimum odds: the shortest price a qualifying bet can be placed at, commonly 1/2 (1.5) or evens (2.0).
• Bet credits: bet365’s term for free bet funds, which can be staked but not withdrawn.
• Expiry: the time you have to use a free bet, often seven days.
• Opt-in: some offers only apply if you tick a box or enter a code when you join.
• Payment method exclusions: deposits through some e-wallets, such as Skrill, may not count towards a welcome offer.
• Wagering requirement: how many times a bonus must be bet through before any winnings can be withdrawn. Capped at 10 times in Great Britain since 19 January 2026.
• Mixed-product promotion: an offer requiring you to use more than one gambling product. Banned in Great Britain since 19 January 2026. Read about the rule changes.
• Matched betting: backing an outcome with a bookmaker and laying the same outcome on an exchange to lock in the value of a free bet.

In-play and settlement

• In-play: betting on an event once it has started.
• Cash out: settling a bet early for whatever the bookmaker offers.
• Partial cash out: settling part of a bet now and leaving the rest running.
• Void bet: a bet the bookmaker cancels, returning the stake. In an acca, a void leg is usually treated as a winner at 1.0, so the rest of the bet carries on.
• Push: a result landing exactly on the line, such as a one-goal Asian handicap won by one goal, in which case the stake is returned.
• Palpable error: an obvious pricing mistake, which bookmaker terms allow them to resettle at the correct price.

Safer gambling tools

Every UK-licensed bookmaker must provide these free tools, and you can switch them on in your account.

• Deposit limit: a cap on what you can pay in per day, week or month.
• Reality check: a pop-up reminding you how long you have been logged in.
• Time-out: a short, fixed break from a site, from 24 hours to six weeks.
• Self-exclusion: closing your account with a bookmaker for at least six months.
• GAMSTOP: a free scheme that self-excludes you from every UK-licensed online gambling site in one go.
• Financial risk check: a check a bookmaker carries out to make sure your spending is sustainable. See our financial risk checks guide.