Arbitrage Betting Calculator
18+ · Gambling can be addictive. The house edge means you lose over time.
- Arbitrage
- 1.44%
- Profit on the total staked, whatever happens
- Guaranteed return
- $1,014.38
- +$14.38 on $1,000.00
- Market total
- 98.58%
- Sum of implied probabilities. Under 100% = arb
Stakes
| Outcome | Odds | Implied | Exact stake | Return | Profit |
|---|---|---|---|---|---|
| Outcome 1 | 2.080 | 48.08% | $487.68 | $1,014.38 | +$14.38 |
| Outcome 2 | 1.980 | 50.51% | $512.32 | $1,014.38 | +$14.38 |
Rounded stakes
Whole amounts are quicker to place and look less unusual than stakes to the cent. We pick the rounding (up or down for each leg) with the best worst-case return on what you stake, so the total can end up a unit or two off.
| Outcome | Stake | Return | Profit if it wins |
|---|---|---|---|
| Outcome 1 | $488.00 | $1,015.04 | +$14.04 |
| Outcome 2 | $513.00 | $1,015.74 | +$14.74 |
| Total | $1,001.00 | Worst case +$14.04 | |
How to use it
- Pick the odds format and a 2-way or 3-way market (3-way is home, draw, away).
- Enter the best price you can get for each outcome, each from whichever bookmaker offers it.
- Enter the total you want to stake across all the bets.
- Check the arb %: green means a guaranteed profit, red means the prices still carry a margin.
- Place the stakes shown, or the rounded ones. Copy the URL to share the calculation.
How arbitrage stakes are calculated
Each price has an implied probability, 1 ÷ decimal odds. A bookmaker's own prices add up to more than 100%: the excess is its margin. When the best prices from different bookmakers add up to less than 100%, you can back every outcome and profit whichever one wins.
stake on outcome i = total × (1/di) ÷ m
guaranteed return = total ÷ m, profit % = 1/m - 1
Staking in proportion to 1/d makes every outcome return the same amount, because stake × odds is then total ÷ m for each one. No other split does better on its worst outcome; our test script checks this against a brute-force search.
Examples
| Market | Odds | Market total | Stakes ($1,000) | Profit |
|---|---|---|---|---|
| 2-way | 2.08 / 1.98 | 98.58% | $487.68 / $512.32 | +$14.38 (1.44%) |
| 3-way | 3.00 / 3.70 / 2.65 | 98.10% | $339.80 / $275.52 / $384.68 | +$19.41 (1.94%) |
| No arb | 1.91 / 1.91 | 104.71% | $500.00 / $500.00 | -$45.00 (-4.50%) |
Rounded to $5, the 2-way example becomes $490 and $515 ($1,005 in total), with a worst case of +$14.20.
Arb % and how calculators differ
"Arb %" gets used for two different numbers. We show the profit on the total staked (1/m - 1), which is what you actually make, and the market total m next to it. Some tools show 1 - m instead, which is slightly smaller. Many calculators also give exact stakes to the cent with no way to round them, or round them without telling you that the profit changed. Ours checks every up or down rounding of each leg and shows the real worst case.
Bookmaker limits: the honest part
The math is guaranteed. Getting paid is not. Bookmakers set their prices expecting to win, and they can restrict accounts that don't lose. The UK Gambling Commission asked large betting operators for their 2024 data, covering 14,923,840 active accounts. 643,779 of them (4.31%) had been restricted in some way. The most common restriction was a reduced maximum stake (2.68% of all active accounts), and 46.78% of restricted customers were in profit, against 25.42% of all customers.
Other things that can turn an arb into a normal bet:
- A price moves or a stake is cut before you place the last leg.
- One bookmaker voids a bet under its terms for obvious or palpable errors, which leaves you with one open side. Read the terms first.
- The two bookmakers settle differently, for example on a player retiring, overtime or a void market.
- Deposit and withdrawal fees, currency conversion or exchange commission, which come off the profit.
Source: UK Gambling Commission, Commercial restrictions by betting operators (23 July 2025). Formulas derived on this page.
Where to use it
Compare esports and CS2 bookmakers on our CS2 betting sites list, or crypto sportsbooks and casinos on crypto casinos. Check what a game keeps with the house edge calculator. Set a budget first, and see our responsible gambling page if it stops being fun.
FAQ
- How do you calculate an arbitrage bet?
- Convert every price to decimal odds and add up 1/odds for each outcome. Below 1 (100%) is an arb. Stake total x (1/odds) / sum on each outcome and they all return the same amount. At 2.08 and 1.98, $1,000 splits into $487.68 and $512.32 and returns $1,014.38 either way.
- What is a good arbitrage percentage?
- Any arb above 0% is a guaranteed profit on paper, but small ones are what you usually find, because bookmakers move prices quickly. Weigh the profit against the chance that a price changes before you place the second bet, and against the risk of the account being limited.
- Is arbitrage betting legal?
- An arb is just ordinary bets placed with different bookmakers, so it's as legal as betting is where you live. The practical problem is that bookmakers can limit or close accounts. In Great Britain the Gambling Commission has said operators are entitled to act in their commercial interests and manage their liabilities.
- Why do bookmakers limit arbitrage bettors?
- Arbers win over time, and bookmakers price their markets expecting most customers to lose. Data the UK Gambling Commission collected from large operators for 2024 found 4.31% of active accounts restricted in some way, and restricted customers were far more likely to be in profit.
- What happens if odds change before I place the second bet?
- Then the arb may be gone and you're left with a normal bet on one side. Re-enter the new price here: the calculator shows whether there's still an arb, and if not, how much the best split loses.