110 betting and casino terms, explained in plain English with worked examples where the maths matters.
Written by Daniel Ward
Updated · Advertiser disclosure
A single bet that combines two or more selections. Every selection must win for the bet to pay out, but the odds multiply together, so the return is bigger than separate bets would give.
£10 on three selections at 2.00, 3.00 and 1.50 pays £90 (2.00 x 3.00 x 1.50 = 9.00 x £10).
Read the guideA way of judging a team by whether it beats the point spread rather than whether it wins the game. A team can win outright and still lose against the spread.
A team favoured by 7 points wins by 3. It won the game but failed to cover, so a bet on it at -7 loses.
Read the guideThe US way of quoting odds. A plus number shows the profit on a 100 stake, and a minus number shows the stake needed to win 100.
At +150 a $100 bet returns $250 ($150 profit plus your $100 stake). At -150 you must stake $150 to win $100.
Read the guideA bet placed well before an event starts, such as a league title or the Grand National. Prices are often bigger than on the day, but if your selection does not take part you usually lose the stake, unless the bookmaker offers a non-runner refund.
A bet that a named player will score at any point during a match. Own goals do not count, and extra time usually does not count unless the rules say so.
Backing every outcome of an event at different bookmakers so that the combined implied probability is under 100%. It is rare, margins are thin, and accounts that do it are often restricted.
Odds of 2.10 on each side of a two-way market imply 47.6% + 47.6% = 95.2%. Staking £100 on each side returns £210 for £200 out, a £10 profit.
A handicap market that removes the draw by giving one side a head start in goals, often in half or quarter steps. Whole-number lines can result in a stake refund, and quarter lines split your stake across two lines.
£10 on a team at -0.25 is £5 on 0 and £5 on -0.5. If the match is drawn, the £5 on 0 is refunded and the £5 on -0.5 loses.
Read the guideTo bet on an outcome to happen. On a betting exchange it is the opposite of laying, which means betting against an outcome.
A selection you must include in every line of a permutation bet, or a result you view as very likely. In a permutation, a banker that loses sinks every line it is in.
The money you have set aside for betting and can afford to lose. It should be separate from rent, bills and savings, and many bettors stake only a small percentage of it on any one bet.
With a £500 bankroll and a rule of 1% per bet, a standard stake is £5.
Read the guideA UK feature that lets you combine several markets from the same match into one bet, such as a team to win, a player to score and over 2.5 goals. The bookmaker prices the combination as a whole because the outcomes are linked.
Read the guideThe panel on a betting site where your selections are collected before you confirm a bet. Check the odds, stake and bet type on the slip before you place it.
A word or number you enter when signing up or depositing to claim a specific offer. Some offers apply automatically, so check whether a code is genuinely needed.
Read the guideA company that takes bets on sports and other events and sets the odds. In the UK a bookmaker needs a Gambling Commission licence, and in the US it needs a licence from each state where it operates.
Read the guideA football market that wins if each team scores at least one goal in normal time. The final result and total number of goals do not matter.
A 2-1 win for either side lands a BTTS Yes bet. A 3-0 win does not.
A full-cover bet on five selections made up of 26 separate bets: 10 doubles, 10 trebles, 5 fourfolds and 1 fivefold. Two winners are needed to get any return.
A £1 Canadian costs £26 (26 bets x £1).
An option to settle a bet before the event ends for an amount the bookmaker offers. The amount reflects the current odds and includes the bookmaker's margin, so it is usually less than the fair value of the bet.
Read the guideAn offer that returns part of your net losses over a set period. Check whether it pays out in cash or as a bonus with wagering requirements attached.
With 10% cashback and £200 of net losses in a week, you receive £20.
Read the guideThe final odds on a market just before an event starts. Because it reflects the most money and information, it is often treated as the best estimate of the true probability.
A measure of whether you took better odds than the closing line. Consistently beating the close is seen as a sign of good bet selection, even though single results can differ.
You back a team at 2.20 and it closes at 2.00. Your price implied 45.5% and the close implied 50%, so you got positive closing line value.
A short, self-imposed break from gambling, commonly 24 hours up to several weeks. The account is locked during the break and reopens when it ends.
Read the guideA bet on the exact final score of a match. The prices are long because there are so many possible scores.
When two or more competitors finish level for a position that pays out. Your stake is divided by the number of dead-heaters, and only that part of the stake is paid at the full odds.
£10 on a 5/1 horse that dead-heats for first with one other: £5 is paid at 5/1 (£25 profit plus £5 stake = £30) and the other £5 loses.
Odds shown as the total return per 1 staked, including your stake. Multiply your stake by the odds to get the return.
£10 at 3.50 returns £35, which is £25 profit plus your £10 stake.
Read the guideA cap you set on how much you can pay into your account per day, week or month. Lowering a limit takes effect at once, while raising it normally has a delay.
Read the guideA bet on two selections where both must win. The odds of the two selections multiply together.
£10 on a double at 2.00 and 3.00 returns £60 (2.00 x 3.00 x £10).
A football market that covers two of the three match results. 1X is home win or draw, X2 is draw or away win, and 12 is home or away win.
A double chance bet on 1X wins if the home side wins or the match is drawn.
A two-way football market where your stake is refunded if the match ends in a draw. Because you are protected against the draw, the odds are lower than for the same team in the match result market.
Splitting your total stake across several selections in one event so that you get the same return whichever one wins. Each stake is inversely proportional to its odds, and the return only beats your total stake if the odds are long enough.
£100 across selections at 3.00 and 4.00: £57.14 on the 3.00 and £42.86 on the 4.00. Either one winning returns £171.43.
Two bets in one: a win bet and a place bet on the same selection. The place part pays a fraction of the odds if your selection finishes in the places, which commonly are the top 2, 3 or 4 depending on the race.
£5 each way (£10 total) at 10/1, 1/4 odds, 3 places. If it places only, the place bet pays £5 x 10/1 x 1/4 = £12.50 plus £5 stake, so £17.50 returned.
Read the guideThe difference between your estimate of the true probability and the probability implied by the odds. A positive edge means the bet is priced in your favour, but your estimate may be wrong.
You rate a team 55% to win and the odds imply 50%. Your estimated edge is 5 percentage points.
Odds where the profit equals the stake. Evens is 1/1 in fractional odds, 2.00 in decimal and +100 in American odds.
£10 at evens returns £20 (£10 profit plus £10 stake).
Read the guideA platform where users bet against each other rather than against a bookmaker. You can back or lay an outcome, and the exchange charges commission on net winnings.
With 5% commission, a £10 net win on an exchange leaves you £9.50.
The average result of a bet if it were repeated many times. It is the probability of winning times the profit, minus the probability of losing times the stake. A single bet can still lose even when its EV is positive.
A £10 bet at 2.50 with a true win chance of 45%: (0.45 x £15) - (0.55 x £10) = +£1.25.
The selection the bookmaker rates as most likely to win, shown with the shortest odds. In US betting the favourite carries a minus sign on the moneyline.
Odds that are locked in when you place the bet, so the return is known in advance. It contrasts with starting price and tote bets, where the final price is set later.
Odds written as a fraction, such as 5/2, showing the profit relative to the stake. The first number is the profit and the second is the stake.
£10 at 5/2 wins £25 profit and returns £35 including your stake.
Read the guideA bonus stake given by a bookmaker. Most free bets are stake not returned (SNR), so you receive only the profit if it wins, and the stake is not paid back.
A £10 free bet at 3/1 that wins pays £30. The £10 stake itself is not returned.
Read the guideSpins on a slot game given as an offer, with no cost from your balance. Winnings often carry wagering requirements and may be capped.
20 free spins at £0.10 per spin are worth £2 of play in total.
Read the guideThe mistaken belief that a result is due because it has not happened recently. Roulette, slots and coin tosses have no memory, so past results do not change the next one.
A fair coin that lands heads five times in a row is still 50% to land heads on the sixth toss.
Legal permission from a regulator to offer gambling to a market. In the UK this is the Gambling Commission, in Ontario it is the AGCO with iGaming Ontario, and in the US it is each state's regulator.
Read the guideThe percentage of each stake that counts towards a wagering requirement. Slots often count in full, while table games such as blackjack can count for much less or not at all.
At 10% contribution, a £100 blackjack stake clears only £10 of the wagering requirement.
Read the guideThe UK's free national self-exclusion scheme. Signing up blocks you from every online gambling site holding a Great Britain licence, for however long you pick.
Read the guideA bet where one side is given a points or goals head start or deficit to even up the contest. The result is judged after the handicap is applied.
Team A -1 beats Team B 2-0. After the handicap it counts as 1-0, so a bet on Team A -1 wins.
The total amount of money wagered on an event, a sport or by an operator over a period. It is a measure of betting volume, not of what the bookmaker earns.
A second bet placed on the opposite outcome to lock in a result or reduce risk on an existing bet. It lowers the possible loss but also the possible win.
£20 on Team A at 5.00 in the final. You bet £40 on Team B at 2.50. Total staked £60, and either team winning returns £100.
A full-cover bet on six selections made up of 57 bets: 15 doubles, 20 trebles, 15 fourfolds, 6 fivefolds and 1 sixfold. There are no singles, so at least two selections must win.
A £1 Heinz costs £57 (57 bets x £1).
How often a slot returns a winning spin of any size. A high hit frequency tends to mean frequent small wins rather than big ones.
A hit frequency of 25% means roughly one spin in four returns something.
The share of total money wagered that an operator keeps after paying winners. It is the operator's side of the same maths as the house edge or margin.
With -110 on both sides of a game and equal money on each, the book holds about 4.55% ($10 kept from $220 staked).
The average percentage of each stake a casino expects to keep over the long run. It is the opposite of RTP, so a game with 96% RTP has a 4% house edge.
Single-zero roulette has a 2.70% house edge (1 in 37). Double-zero American roulette has 5.26% (2 in 38).
Read the guideThe chance of an outcome that the odds suggest. For decimal odds it is 1 divided by the odds. Add up the implied probabilities across a market and the total exceeds 100% because of the margin.
Decimal odds of 4.00 imply 1 / 4.00 = 25%. Fractional odds of 3/1 also imply 25%.
Read the guideBetting on an event after it has started, with odds that change as the action unfolds. Bets can be suspended during key moments, such as a penalty.
The bookmaker's built-in fee on a bet. On a standard US line of -110 each way, the juice is the gap between a fair 2.00 price and the 1.91 you actually get.
At -110 both sides, each side implies 52.38% (110 / 210), so the market totals 104.76% and the vig is 4.76%.
A formula for sizing a stake as a fraction of your bankroll based on your estimated edge. It is very sensitive to a wrong probability estimate, so many people use only a fraction of the result.
Odds of 2.50 (b = 1.5) and a 45% win chance (q = 55%): (1.5 x 0.45 - 0.55) / 1.5 = 8.3% of bankroll.
Identity checks a licensed operator must carry out before paying out or sometimes before you play. You usually upload ID and proof of address.
Read the guideA bet that an outcome will not happen, available on betting exchanges. You act as the bookmaker, and if the outcome does happen you pay the backer.
Laying £10 at 4.00 and winning means you keep the backer's £10 stake, less commission. Losing costs you £30.
The amount you stand to lose on a lay bet. It is the backer's profit if the outcome happens.
A £10 lay at 4.00 has a liability of £10 x (4.00 - 1) = £30.
The US term for the price or number a bookmaker offers on a game. That can be the moneyline, the point spread or the total.
A change in the odds or spread between the time a market opens and the event starts. It can be caused by bets, injury news or other information.
Casino games such as blackjack and roulette run by a real dealer and streamed in real time from a studio. Results come from real cards and wheels, not an RNG.
A cap on how much you can lose over a day, week or month. When it is reached, you are blocked from further play until the period resets.
Read the guideA full-cover bet on four selections made up of 15 bets: 4 singles, 6 doubles, 4 trebles and 1 fourfold. You get a return even if only one selection wins.
A £1 Lucky 15 costs £15 (15 bets x £1).
A full-cover bet on five selections made up of 31 bets: 5 singles, 10 doubles, 10 trebles, 5 fourfolds and 1 fivefold.
A £1 Lucky 31 costs £31 (31 bets x £1).
The bookmaker's built-in profit margin. Add up the implied probabilities of every outcome in a market and anything over 100% is the margin.
Odds of 1.91 on both sides of a tennis match imply 52.4% + 52.4% = 104.7%, so the margin is 4.7%.
A bonus that matches a percentage of your deposit, up to a limit. It almost always comes with wagering requirements.
A 100% match up to £100: depositing £50 gives you £50 in bonus funds.
Read the guideA cap on the stake allowed per spin or bet while a bonus is active. Going over it can void the bonus and any winnings.
Read the guideA bet on which team or player will win outright, with no point spread. It is usually quoted in American odds.
A $100 bet on a +200 underdog that wins returns $300 ($200 profit plus $100 stake).
Read the guideA bonus credited without a deposit, usually small and capped, with wagering requirements and a maximum cashout.
Read the guideA number that shows how likely an outcome is thought to be and how much a bet pays. Odds appear as fractional, decimal or American, and all three can be converted to one another.
5/2, 3.50 and +250 all describe the same price.
Read the guideA promotion that raises the odds on a selected bet above the normal price. Boosts usually have a maximum stake.
A boost takes a 2.00 selection to 2.50. A £10 bet now returns £25 rather than £20.
Odds shorter than evens, meaning you must stake more than you can win. The selection is rated more likely than not to win.
£10 at 1/2 (1.50) returns £15: £5 profit plus your £10 stake.
Read the guideA bet on who will win a competition as a whole, such as a league, tournament or golf major, rather than a single match.
A bet on whether a stat, such as goals or points, will finish above or below a number set by the bookmaker. Whole-number lines can end in a push.
On a line of 2.5 goals, a 2-1 result lands the over (3 goals) and a 1-0 result lands the under.
The US term for a bet that links two or more selections, with every leg required to win.
$10 on a two-leg parlay at +100 each returns $40 (2.00 x 2.00 x $10).
Read the guideA full-cover bet on three selections made up of 7 bets: 3 singles, 3 doubles and 1 treble. You get a return if just one selection wins.
A £1 Patent costs £7 (7 bets x £1).
A line across the reels of a slot on which matching symbols must land to pay out. Some slots have fixed paylines, and others pay in ways or clusters.
A margin of victory set by the bookmaker to even up a game. The favourite must win by more than the spread, and the underdog can lose by less than it or win.
A team at -3.5 must win by 4 or more. At standard -110 odds, $110 staked wins $100.
Read the guideA jackpot that grows with every bet placed on a game or network of games until someone wins it, then resets. Games that feed a big jackpot tend to pay back less on ordinary spins.
A bet on a specific event within a game rather than its result, such as a player's points total or the first scorer.
British slang for someone who places bets.
A bet that lands exactly on the line, such as a total of 48 on a line of 48. The stake is returned and nothing is won or lost.
A team favoured by 7 wins by exactly 7. Bets on either side at -7 are refunded.
A pop-up reminder showing how long you have been playing and how much you have won or lost. Licensed UK casinos must offer them.
Read the guideA bonus given on deposits after your first one, typically a percentage match on a set day.
Read the guideSoftware that produces random outcomes for slots, virtual table games and other digital casino games. Licensed games are independently tested for fairness.
A US set of parlays built from a group of picks, where each parlay combines a fixed number of them. It is similar to a permutation bet in the UK.
Three picks 'by 2' gives 3 two-team parlays: A+B, A+C and B+C.
The percentage of all money wagered that a game pays back to players over a very large number of plays. It is a long-run average and does not predict a single session.
A 96% RTP slot returns on average £960 for every £1,000 wagered.
Read the guideA UK horse racing rule that reduces winnings when a horse is withdrawn before the race starts, because the remaining runners now have better chances. Your stake is not affected.
A horse at 4/1 is withdrawn, which gives a 30p in the pound deduction. £50 of winnings becomes £35 (£50 x 0.70).
A US parlay that combines several bets from one game, such as the winner, a player's points and the total. The legs are linked, so sportsbooks price them with extra margin.
Read the guideA slot symbol that pays or triggers a feature, such as free spins, wherever it lands on the reels without needing to be on a payline.
A formal request to be blocked from gambling at an operator or across all operators for a set period, often six months or more. In the UK you can use GamStop for online sites.
Read the guideThe point where a bet is marked as won, lost, void or pushed and any winnings are paid to your account.
A skilled bettor whose bets bookmakers respect, and who often moves the odds. The opposite is a recreational player.
A bet on one selection to win. It is the simplest bet type and the easiest to track.
£10 on a single at 3.00 returns £30 if it wins, and nothing if it loses.
The amount of money you bet.
The official odds on a horse or greyhound at the moment the race starts. If you take SP, you accept whatever the final price turns out to be.
A bonus that cannot be withdrawn. Only winnings made from it can be cashed out, and the bonus balance is removed when you withdraw.
Read the guideA US parlay in which you move the point spreads or totals in your favour in exchange for lower odds. All legs must still win.
A 6-point NFL teaser moves a -7.5 favourite to -1.5, or a +2.5 underdog to +8.5.
A football market with three outcomes: home win, draw or away win. A draw loses a bet on either team.
A pool betting system in which all stakes go into a pool. After the operator's deduction, the rest is shared among winners, so the payout depends on how many people backed the winner.
A £10,000 pool with 15% deducted leaves £8,500. If £1,000 was staked on the winner, each £1 returns £8.50.
A bet on three selections, all of which must win.
£5 on a treble at 2/1, 3/1 and 1/1 uses decimal odds 3.00 x 4.00 x 2.00 = 24.00, so it returns £120.
A bet on three selections made up of 4 bets: 3 doubles and 1 treble. You need at least two winners to get a return.
A £2 Trixie costs £8 (4 bets x £2).
The selection rated less likely to win, with longer odds. On the US moneyline it carries a plus sign.
A standard stake used to record and compare bets, often a fixed percentage of your bankroll.
With a £1,000 bankroll and 1 unit = 1%, one unit is £10.
A bet where the odds are better than your estimate of the true probability. Estimating that probability well is the hard part.
You think a team has a 40% chance, and odds of 3.00 imply 33.3%. By your estimate, that is value.
A bet cancelled by the operator, for example if a match is abandoned. The stake is returned, and in a multi the void leg is treated as odds of 1.00.
A treble at 2.00, 3.00 and 4.00 with one leg void pays as a double at the remaining odds.
How much a game's results swing around its average. High volatility slots pay less often but can pay larger wins, and low volatility slots pay smaller wins more often.
Read the guideThe amount you must bet before bonus funds or winnings from a bonus can be withdrawn. It is shown as a multiple of the bonus, or of the bonus plus deposit.
A £50 bonus with a 35x requirement on the bonus means £50 x 35 = £1,750 of wagering.
Read the guideAn offer for new customers, such as a free bet or a deposit match. Always read the minimum odds, time limit and wagering terms.
Read the guideA slot symbol that substitutes for other symbols to complete a winning combination. Some wilds expand, stick or carry multipliers.
A bet on four selections made up of 11 bets: 6 doubles, 4 trebles and 1 fourfold. There are no singles, so at least two selections must win to get a return.
A £1 Yankee costs £11 (11 bets x £1).
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