A
American odds (moneyline)
An odds format with a positive value (profit per 100 staked) or negative (stake to win 100). +150 returns €150 profit for €100; −150 needs €150 to win €100.
Related calculator: convertisseur cotes
Asian handicap
A handicap variant removing the draw via fractional lines (−0.5, −0.25). Refunds or splits the stake in certain cases.
B
Back (bet for)
Betting that an event will happen — the classic bet. Opposite to lay on betting exchanges.
Bankroll
The total capital dedicated exclusively to betting, kept separate from personal finances. Managing it well is the key to long-term survival.
Related calculator: roi
Betting exchange
A platform where bettors bet against each other (back vs lay) without a bookmaker, for a commission. Betfair is the main example.
Related calculator: lay couverture
Betting unit
A fixed fraction of the bankroll staked per bet, usually 1 to 3%. Thinking in units rather than currency protects against emotional decisions.
Related calculator: kelly
Bookmaker margin (vig, juice)
The commission built into the odds that guarantees the bookmaker a profit whatever the outcome. Also called "vig" or "overround". Odds without margin would be "fair" odds.
BTTS (both teams to score)
A market betting that both teams will score at least one goal, regardless of the final result.
C
Cash out
An option to settle a bet before the event ends, to secure a profit or limit a loss, at a value calculated by the bookmaker.
Related calculator: cote live
Closing line
The last odds available just before kick-off. Consistently beating the closing line (CLV) is a reliable indicator of profitability.
CLV (closing line value)
The gap between the odds taken and the closing odds. Positive CLV means you bet at better odds than the final market — a sign of value.
Commission
The percentage a betting exchange takes from net winnings, usually 2 to 5%. Must be factored into any hedging calculation.
Related calculator: lay couverture
D
Decimal odds (European)
An odds format where the total return (stake included) equals stake × odds. Odds of 2.50 return €25 for €10 staked. Standard format in Europe.
Related calculator: convertisseur cotes
Double chance
A bet covering two of the three possible outcomes (1X, 12 or X2), reducing risk but also the odds.
Draw no bet
A bet on a team with the stake refunded if the match is a draw. Removes the draw risk for reduced odds.
Drift
A rise in odds over time, indicating the market judges the event less likely than at first.
Dutching
Spreading the stake across several selections in the same event to win the same amount whichever of the covered selections wins.
Related calculator: dutching
E
Expected value (EV)
The average expected profit of a bet over the long term: (probability × odds) − 1. Positive EV means a profitable bet, negative EV a losing one on average.
Related calculator: value bet
F
Fair odds
Odds that would exactly reflect the real probability, without the bookmaker's margin. A reference for measuring value.
Related calculator: comparateur value
Favourite
The selection judged most likely by bookmakers, therefore showing the lowest odds.
Flat betting
A strategy of always staking the same fixed amount, whatever the bet. Simple and robust, ideal for beginners.
Related calculator: roi
Fractional odds (British)
An odds format expressed as a fraction (e.g. 6/4) showing net profit relative to the stake. 6/4 means €6 profit for €4 staked.
Related calculator: convertisseur cotes
Free bet
A bet offered by a bookmaker where only the net profit (excluding stake) is kept. A pillar of matched betting.
Related calculator: matched betting
H
Handicap (spread)
A market where a team gets a fictional goal/point advantage or disadvantage, to balance the odds between favourite and underdog.
Hedging
Placing an opposite bet to reduce risk or guarantee a profit, often via a lay on an exchange or a live bet.
Related calculator: lay couverture
I
Implied probability
The probability that odds imply, calculated as 1 ÷ (decimal) odds. Odds of 2.00 imply 50%. Comparing it to your own estimate reveals value.
Related calculator: probabilites cotes
K
Kelly criterion
A formula calculating the optimal stake based on value and odds, to maximise capital growth. Half-Kelly is recommended in practice to reduce volatility.
Related calculator: kelly
L
Lay (bet against)
On a betting exchange, betting that an event will NOT happen, playing the bookmaker's role. The basis of matched betting and hedging.
Related calculator: lay couverture
Line
The value set by the bookmaker on a threshold market (handicap, total), around which over/under or handicap bets are organised.
Live betting
A bet placed during the event, with odds changing in real time according to the action.
Related calculator: cote live
Live odds
Odds updated continuously during a live event, reflecting the score and time elapsed.
Related calculator: cote live
M
Matched betting
A technique using bookmakers' free bets while covering each bet with an exchange lay, for a near risk-free profit.
Related calculator: matched betting
Minimum (qualifying) odds
The floor odds required for a bet to count towards a bonus or promotion's terms, often 1.50 or 1.80.
Related calculator: optimiser promos
O
Over/Under
A bet on whether a total (goals, points) will be above or below a line set by the bookmaker, e.g. over 2.5 goals.
P
Parlay (accumulator)
A bet combining several selections whose odds multiply. Potential return is high but every selection must win.
Related calculator: parlay
Payout rate (RTP)
The percentage of stakes a bookmaker returns on average to bettors. The higher it is, the better the odds. Its complement to 100% is the bookmaker's margin.
Related calculator: trj
Poisson distribution
A statistical model estimating the probability of a number of goals from offensive and defensive averages. Widely used for football.
Related calculator: poisson
Push (refund)
An outcome where the bet is void and the stake refunded, typically when the score lands exactly on a whole handicap or total line.
R
Real probability
An estimate of the true chance an event occurs, independent of the bookmaker's odds. It's compared to the implied probability to find value.
Related calculator: probabilites cotes
Return (payout)
The total amount received if the bet wins, stake included: stake × odds. Net profit is the return minus the stake.
Related calculator: gains
Risk of ruin
The probability of losing your entire bankroll. Rises sharply when the betting unit exceeds 5% of capital.
Related calculator: kelly
ROI (return on investment)
The ratio of net profit to total staked, as a percentage. Measures a bettor's real profitability over a large number of bets.
Related calculator: roi
Rollover (wagering requirement)
The number of times a bonus must be re-wagered before withdrawal. A x5 rollover on €50 requires staking €250.
Related calculator: optimiser promos
S
Single bet
A bet on one selection. The most basic bet type, opposite to a parlay.
Stake
The amount placed on a bet. The potential return equals the stake multiplied by the odds (for decimal odds).
Related calculator: gains
Stake splitter
A tool calculating how to split a total stake across several selections to reach a profit target or a balanced risk.
Related calculator: repartiteur mises
Steam (odds move)
A rapid, sharp drop in odds caused by a flood of bets, often followed by sharp bettors.
Surebet (arbitrage)
A combination of bets on every outcome of an event, placed at different bookmakers, guaranteeing a profit whatever happens. Rare and quickly limited by bookmakers.
Related calculator: surebet
System bet
A combination of several bets into sub-parlays (e.g. 2 of 3), allowing a win even if some selections fail.
T
Target profit
The net profit aimed for on a bet, from which the required stake is calculated based on the odds.
Related calculator: benefice acquerir
Tilt
An emotional state leading to irrational betting after losses, the main cause of bettors' ruin.
Tipster
A person or service providing betting tips. Reliability is judged on long-term ROI, not a few good tips.
U
Underdog
The selection judged unlikely, showing high odds and a large potential return.
V
Value bet
A bet whose offered odds are higher than the real probability of the event. The only type of bet that is profitable over the long term.
Related calculator: value bet
Value comparator
A tool pitting market odds against estimated probability to instantly reveal the presence and size of value.
Related calculator: comparateur value
Variance
The spread between actual results and theoretical expectation. High in the short term, it smooths out over a large volume of bets.
W
Welcome bonus
A bookmaker's promotional offer for new sign-ups, often with wagering requirements (rollover) to meet before withdrawal.
Related calculator: optimiser promos
X
xG (expected goals)
A metric measuring the quality of chances created, used to estimate a team's real performance beyond the scoreline.
Y
Yield
Betting jargon synonym for ROI: net profit divided by total stakes. A 5% yield over a season is considered excellent.
Related calculator: roi
#
1X2 (full-time result)
The basic football market: 1 = home win, X = draw, 2 = away win. Also called "moneyline" in other sports.
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