What this calculator does
The same side of the same game can carry a slightly different price at two apps. This calculator takes the prices you can see, converts each to a break-even rate, and shows the margin of each app's market, which is how much its two prices add up to over 100%. It also picks the best price for each side across the apps you entered. Nothing is stored and nothing is sent anywhere. The numbers stay in your browser.
It does not tell you which side to bet, and it does not name apps. It tells you what you would pay at each price, so the choice of price becomes a choice you can see.
How to use it
- Open the same market at each app you can legally use where you are, for example the moneyline of one game.
- Type each app's price for side A and for side B in American odds, for example -110 or +130.
- Read the margin column to see which app charges the least on this market.
- Read the best-price boxes to see which app pays most for each side.
The button that fills an example puts in three made-up apps so you can see the layout. The prices are not real and are not an offer from any app.
A worked example
Take three made-up apps listing the same market. The table shows the break-even rate of each side and the margin.
| App | Prices | Break-even A | Break-even B | Margin |
|---|---|---|---|---|
| App 1 | -115 / -105 | 53.5% | 51.2% | 4.71% |
| App 2 | -110 / -110 | 52.4% | 52.4% | 4.76% |
| App 3 | -120 / +100 | 54.5% | 50.0% | 4.55% |
App 1 charges more than App 2 for side A (-115 against -110) and less for side B (-105 against -110). Its margin is 4.71%. App 2 prices both sides at -110 with a margin of 4.76%. App 3 prices side A at -120 and side B at +100, a margin of 4.55%. If you want side B, App 3 is the best price, and if you want side A, App 2 is the best among the three. The best price depends on the side you want, which is why comparing the whole market tells you less than comparing your side.
What a small price gap is worth
On a $100 stake, a win at -105 pays $95.24 in profit and a win at -115 pays $86.96. The gap on one winning bet is $8.28. The break-even rate falls from 53.5% to 51.2%, which is the share of bets you need to win to come out even. If a bettor whose true chance on the side is 50% placed 100 bets of $100 at each price, the difference in average cost would be about $414.08. A single price difference looks small and adds up when you bet often.
That figure is an average and not a promise. Results swing far above and below it over any number of bets, and the price you choose cannot make a losing bet win. It only changes how much each bet costs to make.
Read the whole market, not one price
A short price on one side can be paired with a long price on the other, so the headline number is not enough. App 1 above has a worse price for side A than App 2 and a better one for side B. The margin column adds both sides together and shows the overall cost of the market, which is useful when you are undecided about the side. When you have a side in mind, use the best-price box for it.
Reading the result boxes
After you enter prices, the boxes under the table sum up the comparison. The best price for each side names the app that pays most for it. The lowest margin names the app whose market costs least overall. The two "best versus worst" boxes show how much more a winning $100 bet would pay at the best price than at the worst one you entered, which turns a price difference into dollars. The last box adds the best price for side A and the best price for side B as break-even rates, and when that sum is under 100% the prices from different apps leave a gap, as described above.
Try the example button first, then replace its numbers with the prices on your screen. Because the tool recalculates as you type, it is quick to test what a price one step shorter or longer would do to the result.
Two-way and three-way markets
The calculator is built for two-way markets, where one side or the other wins, such as a moneyline in a sport without draws, a spread or a total. A three-way market, where a draw is a third result, has three prices and a different margin, and entering two of them here would give a wrong answer. If your market has a draw, compare the three prices by converting each to a break-even rate with the odds calculator and adding all three.
Make sure the bets are the same
Compare like with like. The same game, the same market and the same line. A spread of -3 and a spread of -3.5 are different bets, and a whole-number line can end in a push where a half-point line cannot. A moneyline that includes overtime is not the same as one that settles on regulation time. Player props can differ in the number they are set at, or in what happens if the player does not play. If the lines differ, the prices are not comparable, and this calculator will show a difference that is not real.
The article on pushes and voids explains how whole-number lines and half-point lines differ, and the guide to prop bets covers the rules to read on props.
When prices from two apps leave a gap
Occasionally the best price on side A at one app and the best price on side B at another add up to less than 100% when you convert them to break-even rates. For example -105 on one side and +100 on the other add up to 101.2% here, which is over 100% and therefore not a gap. When the sum is below 100%, a bettor could in principle bet both sides across the apps. Such gaps are rare and short-lived, and acting on them has practical limits: prices change, apps set their own limits and rules, and a bet that is voided or settled differently at one app can turn a locked result into a loss. This site does not recommend any of it. The calculator shows the sum so you can see when it happens, nothing more.
Having accounts at more than one app
To compare prices, you need to be able to see them, and that means having an account where you can legally bet. Which apps are available depends on your state, and the regulator publishes the list of approved operators. We do not list individual apps on this site, because we have not verified app-level facts for them. Our state law table shows what we have verified about each state's rules. Keep your deposits and your total staked in one place so that more accounts do not make your spending harder to track.
What the calculator cannot tell you
It cannot tell you whether a price is a good bet. A low margin means a lower average cost, not a winning bet. It cannot account for promotions, boosted prices or the terms behind them, which are covered in the guide to valuing a sportsbook bonus. It cannot predict which way a price will move. And it only looks at two-way markets, with two sides, so it does not cover a three-way market such as a soccer moneyline with a draw.
The margin, in one paragraph
If both sides were priced at -110, each would imply 52.4% and the two together 104.8%. The extra 4.76% is the margin. A market with a lower margin costs less to bet on, on average. Our article on how sportsbooks make money explains where the margin comes from, and the odds calculator works it out for one pair of prices.
Common mistakes when comparing prices
- Comparing different lines, such as -3 at one app and -3.5 at another.
- Comparing one side only and ignoring that the other side of the same market is priced differently.
- Moving money between apps to chase small gaps, and betting more than planned.
- Treating the lowest margin as a reason to bet.
- Forgetting that prices change by the minute and the price on the slip is the one that counts.
A checklist before you bet
- Is the market, the line and the period the same at each app?
- Which app has the best price for the side you want?
- What is the break-even rate at that price, and is your own estimate above it?
- Is the stake within the budget you set before you started?
Words you will meet
- Margin: the amount by which a market's implied chances add up to more than 100%.
- Break-even rate: the win rate a price needs.
- Best price: the longest price available for a side across the apps you entered.
- Line: the number a spread or total is set at.
- Push: a tie with the number, which returns the stake.
Keeping it in proportion
A better price makes betting cheaper, and it does not make it safe. Bet only what you can afford to lose, and treat any result as entertainment spending. If betting stops being fun, the responsible gambling page lists tools and help, and you can call 1-800-GAMBLER at any time.
Frequently asked questions
How do I find the best odds?
Open the same market at each app you can legally use, enter the prices here and read the best price for your side.
What does margin mean in a comparison?
It is how much the break-even rates of the two sides add up to over 100%. A lower margin costs less on average.
Is the lowest margin always the best bet?
No. It means a lower average cost, not a winning bet. If you want one side, the best price for that side is what matters.
Why must the line be the same?
Different lines are different bets. A spread of -3 and one of -3.5 pay on different results, so their prices cannot be compared directly.
Does this calculator store my numbers?
No. It runs in your browser and nothing is sent anywhere.
Does this site tell me which app to use?
No. We have not verified app-level facts, and the state regulator's list of approved operators is the authority on which apps are licensed where you live.