Sports Betting Calculator

Enter a stake and the odds to see the payout, the profit and the implied probability, with the same price shown in American, decimal, fractional and contract formats. Below the tool you will find every other DarkHorse Odds calculator, free, with an example beside each one.

Which Calculator Do I Need?

Start from the situation you are in. Each row points to the one tool built for it.

I want to

Use this

See what a bet pays and what it profits

Bet Calculator

Turn a Bonus Bet into cash I can withdraw

Bonus Bet Calculator

Turn Site Credit into cash I can withdraw

Site Credit Calculator

Hedge a bet that refunds me if it loses

Second Chance Bet Calculator

Get the most out of a Profit Boost token

Profit Boost Calculator

Lock in profit on a bet I already hold

Hedge Calculator

Cover both sides at two sportsbooks for a fixed margin

Arbitrage Calculator

See the same price in American, decimal, fractional or contract odds

Odds Converter

Compare what Kalshi, Polymarket and other venues charge for the same trade

Prediction Market Comparison

Work out the real odds behind a prediction market fill after fees

Prediction Market Odds Converter

All Calculators

Every tool is free and takes American odds by default. Each card carries one example so you can check the tool against the math before you trust it.

Promo Conversion

The four promotion types DarkHorse Odds has a Bet Finder for. Site Credit and Bonus Bets look alike but convert very differently, so pick the calculator that matches the terms of your offer, not its name.

Bonus Bet Calculator

Convert a Bonus Bet into withdrawable cash. Enter the promotional amount, the bet odds and the hedge odds to see the hedge stake and the cash you keep either way.

Example

A $100 Bonus Bet at +500, hedged at -585 elsewhere, keeps about $73 whichever side wins, close to the typical 70% conversion.

Open calculatorRead the guide
Site Credit Calculator

Convert sportsbook Site Credit into cash you can withdraw. Enter the credit amount, the bet odds and the hedge odds to see the hedge stake and the result on both outcomes.

Example

$100 of Site Credit bet at -115 and hedged at +115 lands at about $100 either way, because a Site Credit stake is returned with the winnings.

Open calculatorRead the guide
Second Chance Bet Calculator

Hedge any Second Chance Bet, including no-sweat bets and bet-back tokens. Enter the bet, the hedge odds and the refund type to see a hedge that pays the same whether the first bet wins or loses.

Example

Enter a $100 bet at +200 with a Bonus Bet refund and the tool shows the hedge stake and the identical profit on both paths, so the refund type decides the value, not luck.

Open calculatorRead the guide
Profit Boost Calculator

Work out how to hedge a Profit Boost. Enter the odds, the boost percentage and the hedge odds to see the boosted payout and the stake that locks in the added value.

Example

A 50% Profit Boost on +100 pays like +150, so a $100 stake profits $150 instead of $100, and the boosted line can turn an ordinary market into an arbitrage.

Open calculatorRead the guide

Strategy

Hedge Calculator

Determine how much to hedge a bet you already placed. Enter the original stake and odds plus the odds available now to see the hedge stake and the profit on either result.

Example

$50 on a future at +1200 pays $650. If the opponent is now -200, a $433.33 hedge locks in about $166.67 whichever side wins.

Open calculatorHedge or let it ride?
Arbitrage Calculator

Cover every outcome so the profit is the same whatever happens. Enter the odds from each sportsbook and a total budget to see how to split the stakes and the margin you lock in.

Example

+105 at one book and -95 at another sum to 97.5% implied probability. A $500 budget splits $250.16 and $249.84 and returns $512.83 either way, a locked-in $12.83.

Open calculatorRead the guide

Pricing and Odds

Odds Converter

Convert any price between American, decimal, fractional and contract odds, with the implied probability alongside, plus lookup tables for every common line.

Example

-150 American is 1.6667 decimal, 2/3 fractional, 60% implied probability and a 60¢ contract.

Open calculatorRead the guide

Prediction Markets

Prediction Market Comparison

Compare what one trade costs across venues. Enter the amount and the contract price to see the contracts bought, the fee, the profit and the odds at Kalshi, Polymarket and eight other markets side by side.

Example

$100 at a 60¢ contract buys 166 contracts before fees. The tool shows how many you actually get, and at what effective price, at each venue.

Open calculatorSingle trade tool
Prediction Market Odds Converter

See what you actually paid per contract, what odds that price really is, and how much of it was fee. Enter the amount, the contract price and the payout from a filled order.

Example

A 40¢ contract prices the outcome at +150. Enter the payout you were quoted and the fee embedded in it falls out as an adjusted price.

Open calculatorCompare venues

Coming Next

Parlay, round robin, SGP correlation, implied probability, vig, no-vig, devig, expected value, Kelly criterion and qualifying bet calculators are being finished and will be added here as each one goes live.

How the Calculators Fit Together

The Pricing Pipeline

Every sharp decision starts with a price. The Odds Converter puts any line into the format you think in and shows the implied probability behind it. Because a two-sided market always adds up to more than 100%, the next step is stripping the sportsbook's margin to find the fair odds, which is what the no-vig and devig tools will do when they go live. Compare those fair odds with the price you are being offered and you have the expected value of the bet, and from the expected value and your bankroll the Kelly criterion tells you how much to stake.

Odds ConverterDetermining Fair Odds guide

The Promo Triad

Sportsbook promotions arrive as one of three things, and the calculator you pick has to match the terms, not the marketing name. A Bonus Bet pays winnings only, so it is worth well under face value. Site Credit returns the stake with the winnings, so it converts near 100%. A Second Chance Bet is your own money with a refund attached, and the refund arrives as one of the other two. The same $500 token at +200 hedged at -150 shows an 80% conversion as a Bonus Bet and 120% as Site Credit, a 40-point swing on identical inputs, which is why the choice matters more than any number you type.

Bonus BetSite CreditSecond Chance Bet

Frequently Asked Questions

For a positive line, profit equals the stake multiplied by the odds divided by 100, so $100 at +150 profits $150 and pays $250 in total. For a negative line, profit equals the stake multiplied by 100 divided by the odds, so $100 at -150 profits $66.67 and pays $166.67. The Bet Calculator at the top of this page does both and shows the implied probability alongside.

Implied probability is the win rate a price is quietly assuming. For a negative American line it is the odds divided by the odds plus 100, so -150 implies 60%. For a positive line it is 100 divided by the odds plus 100, so +150 implies 40%. It includes the sportsbook's margin, which is why the two sides of a market add up to more than 100%.

The excess is the vig, the sportsbook's built-in margin. A standard -110 and -110 market implies 52.38% on each side, 104.76% in total, so the book keeps about 4.5% of the money wagered over time. Removing the vig gives the fair odds, and comparing fair odds with the price you are offered is how expected value is found.

Go by the terms, not the name on the offer. If the stake is not returned on a win, it is a Bonus Bet. If the stake comes back with the winnings but cannot be withdrawn until it is bet, it is Site Credit. If you bet your own money and get a refund only if it loses, it is a Second Chance Bet, and the refund itself will be one of the first two. A percentage added to your winnings is a Profit Boost.

Arbitrage opens both sides of a market fresh, at two sportsbooks whose prices disagree, so that the combined implied probability sits under 100% and the return is fixed before anything is placed. Hedging closes a position you already hold by betting the other side at whatever odds are available now. The math is the same equalization; the difference is whether one of the bets already exists.

Next Steps

The calculators show you the math on one bet. The guides show you how to find those bets every day.

What Is Matched Betting?

How hedged bets turn sportsbook promotions into supplemental income, from the first qualifying bet onward.

Read guide

Intro to +EV Sports Betting

What positive expected value means, where true probabilities come from, and why variance dominates short samples.

Read guide

Matched Betting Terminology

Every term the calculators use, from hedge and implied probability to rollover and Site Credit, defined in one place.

Read guide

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