Our free betting calculators do the sums behind a price for you. Each one takes a few numbers and shows what the odds really say, so you can judge a bet before you place it, or decide to skip it.
They are tools for judging prices. However, none of them can tell you who will win, and no calculator turns betting into a way to make a profit. Most bettors lose over time.
All our betting calculators
- Odds converter: first, switch between decimal, fractional and American odds and see the implied %.
- Fair odds calculator: next, enter 2 or 3 prices, so you can see the book %, the margin and the fair odds.
- Expected value calculator: stake, odds and your win chance give the EV, the break-even chance and your fair odds.
- Kelly calculator: then size a stake from your odds, chance, bankroll and fraction.
- Betting variance calculator: simulates 40 bettors to show how far luck can swing results.
- Free bet calculator: the value of a free bet and also of the whole offer, after the qualifying bet.
- CLV calculator: compares the odds you took with the closing odds, for example 2.20 against 2.00.
- Betting ROI calculator: profit, yield, ROI on bankroll and average stake from your record.
- Drip feed calculator: checks in-play goal bets added while a match is still 0-0.
- Blackjack strategy calculator: the basic strategy play for each hand.
Horse racing calculators
- Each-way calculator: returns if your horse wins, places or loses, with place terms and Rule 4.
- Best odds guaranteed calculator: your price against the SP, and what BOG adds.
- Each-way value calculator: checks a bookmaker’s each-way price against exchange win and place prices.
- Extra place calculator: lay stakes and profit for every finishing position when a bookmaker pays extra places.
How to use it
Start with the question you have. For example, if you want to know what a price means, use the odds converter. Next, if you want to know whether the price is too short, the fair odds and EV tools come in.
Each tool explains its inputs on the page, so you won’t need to guess. Also, every calculator links to a full guide, such as our value betting guide, which explains the maths step by step.
A worked example using three betting calculators
Worked example
A team is priced at 2.40. First, the odds converter shows an implied chance of 1 ÷ 2.40 = 41.7%.
Next, say you rate the chance at 45%. The EV calculator then gives 0.45 × 2.40 − 1 = +£0.08 per £1 staked, or +£0.80 on a £10 stake. Your fair odds are 1 ÷ 0.45 = 2.22.
Finally, the variance calculator shows that even a real edge like this can leave you behind after hundreds of bets.
What the result means
A betting calculator is only as good as the numbers you give it. So if your 45% is really 40%, that same bet has a negative EV. Treat every result as an estimate, and remember that a single bet can lose whatever the maths says.
Our Value Predictor gives statistics, not tips. In the same way, these betting calculators help you check a price, not decide to bet.
Related guides and calculators
For independent guidance on gambling in the UK, see the Gambling Commission’s advice for the public.
18+ only. Betting should be fun, and every bet can lose. Set a budget you can afford to lose and stick to it. For free, confidential support, visit BeGambleAware.org or call the National Gambling Helpline on 0808 8020 133.