Strip the bookmaker margin to find the true fair odds and probability.
Arbitrage Calculator
Find guaranteed profit opportunities across two bookmakers.
$
ARB FOUND
Stake on Outcome 1
—
Stake on Outcome 2
—
Guaranteed Profit
—
ROI
—
Back & Lay Calculator
Calculate lay stakes for Betfair exchange hedging. Back at a bookmaker, lay on the exchange.
$
%
Lay Stake
—
Profit if Back Wins
—
Profit if Lay Wins
—
Betfair Liability
—
Bonus Bet Turnover Calculator
Convert bonus/free bets into guaranteed cash. Bonus bet stake is not returned — only profit.
$
%
Lay Stake
—
Guaranteed Profit
—
Retention %
—
Betfair Liability
—
No Vig / Fair Odds Calculator
Remove the bookmaker's margin to find true fair odds and probabilities.
Fair Odds 1
—
Fair Odds 2
—
Fair Odds 3
—
True Prob 1
—
True Prob 2
—
True Prob 3
—
Overround
—
Vig / Margin
—
Vig Calculator
See exactly how much the bookmaker is taking from both sides of a two-way market.
Bookmaker's Edge
—
Vig / Margin
—
Overround
—
Fair Odds 1
—
Fair Odds 2
—
Implied Prob 1
—
Implied Prob 2
—
True Prob 1
—
True Prob 2
—
Kelly Criterion Calculator
Determine optimal bet sizing based on your edge and bankroll.
%
$
+EV BET
Full Kelly %
—
Recommended Stake
—
Expected Value / Bet
—
Edge %
—
Conservative Sizing
Quarter Kelly
—
—
Half Kelly
—
—
Full Kelly
—
—
Expected Value Calculator
Determine whether a bet has positive expected value (+EV).
%
$
+EV BET
Expected Value
—
EV % per Bet
—
Break-even Probability
—
Your Edge
—
Odds Converter
Enter odds in any format — decimal (2.50), fractional (3/2), or American (+150 / -200).
Decimal
—
Fractional
—
American
—
Implied Probability
—
Common Odds Reference
Decimal
Fractional
American
Implied Prob.
1.50
1/2
-200
66.67%
1.80
4/5
-125
55.56%
1.91
10/11
-110
52.36%
2.00
1/1
+100
50.00%
2.50
3/2
+150
40.00%
3.00
2/1
+200
33.33%
4.00
3/1
+300
25.00%
5.00
4/1
+400
20.00%
10.00
9/1
+900
10.00%
21.00
20/1
+2000
4.76%
Hedge / Cash Out Calculator
Lock in a guaranteed profit on an existing bet by hedging the opposite outcome.
$
Hedge Stake
—
Profit if Original Wins
—
Profit if Hedge Wins
—
Guaranteed Profit
—
Every posted price includes the bookmaker's margin (the vig). Removing it reveals the fair odds, which is the sharp estimate of an outcome's real probability. Comparing a bookmaker's price to the fair price is the foundation of value and EV betting.
How to use it
Enter the odds for each outcome of the market (leave the third box blank for a two-way market).
The calculator normalises the implied probabilities so they sum to 100%.
Read the fair odds and fair probability for each outcome.
Worked example. A two-way market priced 1.90 / 1.90 implies 52.6% each, summing to 105.2%. Stripping the 5.2% margin gives fair odds of 2.00 / 2.00, or a true 50% each.
Use the fair price from a sharp bookmaker as your benchmark, then look for softer books offering more. That gap is your edge, which the DegenToPro +EV finder surfaces automatically. See also closing line value.
Frequently asked questions
What does no-vig mean?
Vig (or juice) is the margin a bookmaker builds into its prices so implied probabilities sum to more than 100%. A no-vig calculation removes that margin so the probabilities sum to exactly 100%, giving the fair odds.
Which bookmaker's odds should I no-vig?
Use the sharpest available price, typically a low-margin bookmaker or a market-leading exchange, because its no-vig line is the most accurate estimate of true probability.
How is no-vig used to find value bets?
If a soft bookmaker offers higher odds than the sharp no-vig fair odds, the bet has positive expected value. The bigger the gap, the bigger the edge.