Betting Calculators: Odds, Returns, Margin and Free Bets
Ten free calculators for the sums every bettor runs into: what a bet pays, what the odds say about probability, how much margin the bookmaker has built in, what an accumulator or an over/under line returns, and what a free bet or a money-back offer is really worth. They run in your browser, with no sign-up.
None of them predicts results or promises profit. They show the arithmetic — how much you can win, how much you can lose and which terms change the outcome — so you can check a price before you place the bet.
Start with these two
Most questions about a bet come down to two numbers: the return and the probability the odds imply.
Bet payout calculator
Total return, net profit, the probability implied by the odds and the win rate you need to break even at that price.
Odds to probability
Turns decimal odds into implied probability, sums a whole market and shows the bookmaker margin and fair odds without it.
Odds and probability
Tools for reading a price: the reverse calculation, the bookmaker's margin and odds formats.
Probability to odds
Fair odds and odds with a margin from your own probability estimate, for one outcome or a 1X2 market, plus the odds implied by a stake and a payout.
Bookmaker margin
Overround of a market, odds with the margin removed four ways, the mark-up on each outcome and a comparison of every market in one match.
Odds converter
Converts between decimal, fractional and American odds and shows the implied probability of each price.
Bet slips and markets
From a single selection to a multi-leg slip and Asian totals lines.
Accumulator calculator
Combined odds, returns and net result of an acca, with voids and partial settlement, the margin that builds up across legs and the bonus needed to offset it.
Over/under calculator
Over and under bets on 2.5, 3.0, 2.25 and 2.75 lines: win, push, half win or half loss for any final score.
Free bets and bet insurance
Promotions look generous on a banner; these two tools put a cash value on them.
Free bet calculator
What a free bet pays with the stake not returned or returned, how much survives a wagering requirement, and how much cash a hedge locks in.
Bet insurance calculator
The hedge stake that covers a bet, the fair price of a bookmaker's paid insurance and the value of a money-back first bet offer.
Budget and risk
A limit set in advance is easier to keep than one decided after a losing run.
Monthly betting budget
Your monthly limit, what is already spent, what is left, a safe daily pace, projected spend and a hard stop.
Questions about the calculators
Are the calculators free? Do I need an account?
They are free and work in the browser without registration. Enter your numbers and the result updates straight away.
Do these tools predict match results?
No. They calculate returns, implied probability, margin, bonus terms and risk from the numbers you enter. A probability taken from odds already contains the bookmaker's margin and is not a forecast.
Which calculator should a beginner open first?
The payout calculator and odds to probability. Between them they explain the difference between stake, return, net profit and the chance a price implies.
Can I type decimal commas or thousands separators?
Yes. Decimals can be entered with a point or a comma, and amounts such as 1,000 or 12,500.75 are read correctly.
Is there a Russian version?
Yes. Goodbets started as a Russian-language site with more than 50 calculators; each English page links to its Russian counterpart in the header.