Calculator guide · 6 min read
Free bet calculator: cover stakes, retention and the best odds
A free bet only has value if it wins. Covering it with a bet on the other outcome at a second bookmaker turns that into a result you know in advance. This page is the calculation: a calculator, the inputs, the formulas, the share of the free bet you keep, which odds work best, three-way markets and Austria's betting fee.
Updated 22 October 2026
Contents
The free bet calculator
Enter the free bet and the odds exactly as they appear on the bet slips; a comma or a full stop both work as the decimal mark. The example values are the worked example below: a €20 free bet at 4.00, covered at 1.30 at a second bookmaker.
The inputs
- Free bet amount (F). The value of the free bet, for example €20.
- Type. Stake not returned (SNR), the usual kind: a win pays F × (odds − 1). Or stake returned (SR): a win pays F × odds.
- Free bet odds. The price you put the free bet on, at or above the promotion's minimum odds.
- Cover odds. The best price for the opposite outcome at another bookmaker. On a three-way market, one price for each of the two other outcomes.
Why it works without an exchange, and what free bets are, is explained in the free bets guide. This page is the arithmetic.
The formulas
The cover bet is sized so that it pays exactly what a winning free bet pays:
SNR: cover stake = F × (odds − 1) / cover odds
SR: cover stake = F × odds / cover odds
Your result is the same whatever happens, and the retention rate is the share of the free bet's face value you keep:
SNR result = F × (odds − 1) − cover stake
SR result = F × odds − cover stake
retention = result / F
Worked example: €20 at 4.00
A winning free bet pays €20 × 3.00 = €60.00.
| Cover odds | Cover stake | Result either way | Retention |
|---|---|---|---|
| 1.40 | €42.86 | +€17.14 | 86% |
| 1.30 | €46.15 | +€13.85 | 69% |
At 1.40 the cover is €60.00 / 1.40 = €42.86 and you keep €60.00 − €42.86 = €17.14 either way; if the cover wins, it pays €42.86 × 1.40 = €60.00, €17.14 more than you staked. That price pair is unusually good: 1/4.00 + 1/1.40 = 0.964, below 1, so the two prices would be a sure bet even with cash. A more typical cover price of 1.30 keeps €13.85.
For an SR free bet with the same prices (4.00 and 1.30) the cover stake is €80.00 / 1.30 = €61.54 and the result €18.46, a retention of 92%.
All figures assume every bet is accepted at the shown odds and stands.
Which odds work best
With SNR free bets, higher free-bet odds usually keep more, because the stake you lose matters less in proportion. Here is the same €20 SNR free bet at different price pairs, each with a cover price that roughly matches a typical market:
| Free bet odds | Cover odds | Cover stake | Result | Retention |
|---|---|---|---|---|
| 2.50 | 1.60 | €18.75 | €11.25 | 56% |
| 3.00 | 1.45 | €27.59 | €12.41 | 62% |
| 4.00 | 1.30 | €46.15 | €13.85 | 69% |
| 6.00 | 1.18 | €84.75 | €15.25 | 76% |
Typical retention for SNR free bets covered at a second bookmaker is somewhere around 55 to 80% in examples like these, more with unusually close prices. The trade-off: higher odds tie up much more cash in the cover bet (€84.75 at 6.00 versus €18.75 at 2.50), and large cover stakes are more likely to hit a stake limit. Check the minimum odds and the maximum odds in the promotion's terms too; some free bets cap the odds.
With SR free bets the odds matter much less, because the stake comes back anyway. Retention is close to the combined price quality, often 85 to 95%, at almost any odds.
Three-way free bets (1X2)
On a football match result you cover the two other outcomes, ideally each at the best price available. Each cover uses the same formula with its own odds:
cover stake X = F × (odds − 1) / odds X
A winning free bet pays €20 × 3.50 = €70.00. Home win at 1.75 at Bookmaker B: €70.00 / 1.75 = €40.00. Draw at 3.80 at Bookmaker C: €70.00 / 3.80 = €18.42. Cash staked: €58.42.
| Outcome | Payout | Cash staked | Result |
|---|---|---|---|
| Away win (free bet) | €70.00 | €58.42 | +€11.58 |
| Home win | €70.00 | €58.42 | +€11.58 |
| Draw | €70.00 | €58.42 | +€11.58 |
Retention in this example: 58%, if all three bets are accepted at the shown odds and stand. The draw payout is €18.42 × 3.80 = €70.00 after rounding.
Three-way conversions usually keep less than two-way ones, because two cover bets each carry their bookmaker's margin, and three bets mean three chances for a price to move. Two-way markets such as tennis, over/under or basketball are usually simpler.
With Austria's betting fee
Austria charges a betting fee (Wettgebühr) of 5% of the stake. The bookmaker owes it, and most absorb it, but some pass it on by reducing the payout or the stake. For the calculation, replace the cover odds with the effective odds after the fee. If 5% is deducted from the payout, that is cover odds × 0.95.
The €20 SNR free bet at 4.00, cover at 1.30, but the cover bookmaker deducts 5%: effective odds 1.30 × 0.95 = 1.235. Cover stake €60.00 / 1.235 = €48.58, result €11.42, retention 57% instead of 69%.
How a bookmaker treats the fee is in its terms or shown on the bet slip. The Austrian betting fee guide has the details.
Before you place the bets
- Check the free bet type (SNR or SR), minimum and maximum odds, eligible markets and expiry.
- Confirm both sides are the same event, the same market and the same settlement period.
- Place the bet whose price is most likely to drop first, usually the cover, then recalculate the other with the price you got.
- On the bet slip, make sure the free bet is actually selected, not your cash balance.
The free-bet calculator in the ArbVantage app does this arithmetic for one or two cover bets, prices in known betting fees and ranks current price pairs by retention for a given bookmaker. Free bets are usually one part of matched betting, the method of working through bookmaker promotions with cover bets.
Frequently asked questions
Which odds should I use for a free bet?
For stake-not-returned free bets, higher odds usually keep more, often 3.00 to 6.00 in practice, as long as the cover price is close and you have enough cash for the larger cover stake. For stake-returned free bets the odds matter much less. Always stay within the promotion's minimum and maximum odds.
What is the retention rate?
The share of the free bet's face value you keep after covering it: result divided by the free bet amount. A €20 free bet that leaves €13.85 either way has a retention rate of about 69%.
Can I withdraw a free bet as cash?
Not directly. A free bet is betting credit that only pays if the bet wins. Covering it with a bet on the other outcome turns part of its value into a result you know in advance, if both bets are accepted and stand. The bonus terms can add wagering on the winnings before you can withdraw.
Is a covered free bet risk-free?
No. Odds change between the two bets, bets can be voided and bonus terms can restrict the payout. The calculated result only holds if every bet is accepted at the shown odds and stands.
Sources
- RIS: Gebührengesetz 1957, § 33 TP 17 (Austrian betting fee) (in German)
- Unternehmensserviceportal (USP), Austria: Wettgebührenabrechnung (in German)
- Wikipedia: Matched betting
As of October 2026. Bookmakers' rules, odds and offers change; their current terms and betting rules always apply.
A free bet is a bookmaker's promotion, not an entitlement, and a single void can cost more than the free bet was worth. Only use money you can do without. Our responsible gambling page lists free help in Austria and Germany.
Information, not betting, legal or tax advice. 18+.