Sports Betting Calculators: 13 Free Odds and Probability Tools
Sports betting calculators turn odds into probabilities and lines into stake sizes. This hub collects 13 of them, covering arbitrage, expected value, the Kelly criterion, parlays, round robins, vig and more. Each calculator has its own page with the formula, a worked example using US sportsbook pricing (American odds first, decimal in parentheses) and an FAQ. Click any card for the full breakdown, or read the AI model breakdown to see these formulas applied to real games.
All 13 sports betting calculators
Kelly Criterion Calculator
Kelly Criterion
What percentage of your bankroll to stake, with half and quarter Kelly
Open calculator →Parlay Calculator
Parlay
Parlay odds, payout, profit and the chance every leg hits
Open calculator →Round Robin Calculator
Round Robin
By 2s, by 3s or full cover: total cost, max payout and what one loss pays
Open calculator →Expected Value Calculator
Expected Value
The one number that says whether a bet wins or loses over time
Open calculator →Implied Probability Calculator
Implied Probability
Convert odds into the market's win probability and find the side with value
Open calculator →Vig Calculator
Vig Calculator
See how much juice the sportsbook takes on every bet and shop for the lowest
Open calculator →Sportsbook Hold Calculator
Hold
The built-in margin on a market with three or more outcomes
Open calculator →No-Vig Fair Odds Calculator
No-vig Fair Odds
Strip out the juice to see the fair odds on a game
Open calculator →Odds Converter
Odds Converter
Convert American, decimal and fractional odds and implied probability
Open calculator →Arbitrage Calculator
Arbitrage / Hedge
Split stakes across two books to lock in a profit, or hedge an open bet
Open calculator →Bonus Bet Conversion Calculator
Bonus Conversion
Turn a bonus bet into locked-in cash with the right hedge stake
Open calculator →Point Spread Calculator
Point Spread
Turn spread prices into cover probability and see whether the line is shaded
Open calculator →Poisson Distribution Calculator
Poisson Distribution
Estimate the hit rate on totals and over/unders from average scoring
Open calculator →Which betting calculator should I use?
- →Find out whether a bet makes money over the long run：Expected Value Calculator
- →Decide what percentage of your bankroll to put on a bet：Kelly Criterion Calculator
- →Price a parlay: total odds, payout and the chance every leg hits：Parlay Calculator
- →Cost out a round robin by 2s, by 3s or full cover, and what one loss pays：Round Robin Calculator
- →Convert odds to win probability or compare vig across sportsbooks：Implied Probability Calculator
- →Estimate the hit rate on a total or over/under from average scoring：Poisson Distribution Calculator
Sports betting calculator FAQ
Are the betting calculators free? Do I need an account?+
All 13 calculators are free and need no login; enter odds or a bankroll and the result updates instantly. You only need a Mysports.AI account if you want to save the bets you price into a bet log and track your bankroll curve over time.
Do the calculators take American odds?+
The inputs use decimal odds because the math is simpler: -110 is 1.91, +150 is 2.50. Paste your sportsbook's American price into the Odds Converter first, then carry the decimal value into any other tool. The Odds Converter itself defaults to American -110.
How are parlay odds calculated?+
Parlay odds multiply. A $100 three-leg parlay at +60 (1.6), +70 (1.7) and +80 (1.8) pays $100 × 1.6 × 1.7 × 1.8 = $489.60. The parlay calculator also shows the profit and the combined probability every leg needs to hit for the ticket to break even.
Do I have to bet exactly what the Kelly criterion says?+
No. Full Kelly is volatile, so most bettors use half or quarter Kelly. The Kelly criterion calculator shows all three stakes in dollars so you can pick the level of risk you are comfortable with, and it is common to cap any single bet at a few units.
Can these calculators guarantee a profit?+
No. A calculator only converts the odds and win probability you enter into a mathematical result, and the result is only as good as your probability estimate. To test your estimates, log every bet in a bet tracker and compare predicted win rates with actual results over hundreds of bets.
Done calculating? See how the AI reads today’s games
A calculator answers the formula; the AI answers the game. Mysports.AI compares model win probability against market odds every day and flags the prices that look mispriced.
For informational purposes only. Sports betting is legal in 39 states and D.C.; rules and minimum age vary by state. 21+. Gambling problem? Call 1-800-GAMBLER.
Odds and vig conventions follow standard US sportsbook pricing (-110 on spreads and totals). The tax line is based on IRS Topic 419 and the Form W-2G instructions (rev. 01/2026); it is not tax advice.