Free bet value is what a free bet or welcome offer is really worth to you in pounds and pence. A “£30 free bet” is not worth £30. Its true value depends on whether the stake comes back, the odds you use it at, and the terms attached.
This guide shows you how to work out that number, so you can compare offers on the maths rather than the headline.
Read the transcript
What is a welcome offer really worth? Let's put a number on it.
Here's a typical offer. Bet ten pounds, and get thirty pounds in free bets.
First, the qualifying bet. At a five per cent margin, a ten pound bet costs you about forty-eight pence on average.
Next, the free bets. Stake not returned means you only keep the winnings. At odds of three, a one pound free bet wins two pounds about a third of the time. After the margin, that's worth roughly sixty-three pence.
So thirty pounds of free bets is worth about nineteen pounds. Take off the qualifying cost, and the offer is worth roughly eighteen pounds fifty, on average.
Terms change the sums. Minimum odds, expiry dates and split free bets all matter. That's why we rank offers by estimated value, not headline size.
Please bet responsibly.
The short version
- Most UK sports free bets are “stake not returned” (SNR). You keep only the winnings, not the stake.
- At fair odds, an SNR free bet is worth stake × (1 − 1 ÷ odds). So £30 at 3.0 is worth about £20.
- The qualifying bet usually costs a little, because of the bookmaker’s margin.
- Minimum odds, expiry dates, split free bets and market limits can all cut the value.
Stake not returned vs stake returned
With a stake not returned free bet, a winning £10 free bet at 3.0 pays £20, not £30. That is because the £10 stake was never yours. So the value is the stake times (odds − 1) times the chance of winning.
With a stake returned (SR) free bet, the full return comes back, stake included. That works like a normal bet with someone else’s money. As a result, an SR free bet at fair odds is worth close to its face value. However, SR free bets are rare on UK sports offers, so always check the terms.
How to work out free bet value
For an SNR free bet, the formula is: value ≈ stake × (odds − 1) × p, where p is the real chance of the bet winning. If the odds are fair, p = 1 ÷ odds, so the formula becomes stake × (1 − 1 ÷ odds).
That means longer odds keep more of the free bet value. Here is a £30 SNR free bet at different fair odds:
| Odds used | Chance to win | Value |
|---|---|---|
| 1.50 (1/2) | 66.7% | £10.00 |
| 2.00 (evens) | 50.0% | £15.00 |
| 3.00 (2/1) | 33.3% | £20.00 |
| 5.00 (4/1) | 20.0% | £24.00 |
| 10.00 (9/1) | 10.0% | £27.00 |
But longer odds also bring much bigger swings. At 10.0, the free bet wins nothing 9 times in 10. So the value is an average over many offers, not what you get each time. Our guide to betting variance explains why that matters.
A full welcome offer example
Worked example
The offer: bet £10, get £30 in free bets (SNR).
Step 1: the qualifying bet. You bet £10 on one side of a two-way market priced at 1.90 each way. Those prices imply 52.6% each, so the book adds up to 105.3%. The fair chance is 50%. So the expected loss is 10 × (0.5 × 1.90 − 1) = −£0.50.
Step 2: the free bets. You use the £30 at odds of 3.0. At fair odds, that is worth 30 × (1 − 1 ÷ 3) = £20.00. But real odds carry a margin too. If 3.0 includes a 5% margin, the true chance is 33.33% ÷ 1.05 = 31.75%. Then the value is 30 × 2 × 0.3175 = £19.05.
Step 3: the total. The free bets are worth about £19.05 after the margin, so the whole offer is worth about £18.55 after the qualifying bet (£19.05 − £0.50).
Use the calculator below to work out free bet value for any offer. Choose SNR or SR, then enter the stake and the odds you plan to use.
Free bet value calculator
This is the same expected value maths that sits behind every bet. Our guide to expected value betting covers it in more depth, and our page on fair odds shows how to remove the margin from a price.
Terms that cut free bet value
The headline number is only the start. Read the full terms, because these four can each take a big bite.
Minimum odds
Many offers say the qualifying bet or the free bets must be at odds of 1.50 or more. That is fine for the free bet, since you want longer odds anyway. However, a minimum on the qualifying bet stops you using a short price with a small margin, so the cost can go up.
Expiry
Free bets often expire after 7 days, and some sooner. An unused free bet is worth £0. So if you cannot find a market you would bet on in that time, the true value is nil.
Split free bets
A £30 offer is often paid as 3 × £10 or 6 × £5. The value is the same if you use each one at the same odds. But splits often come with fixed uses, such as one for an acca and one for a bet builder. Those markets tend to carry higher margins, which lowers the value.
Market restrictions
Some free bets can only go on one sport, one event or one bet type. Also, accas and bet builders usually carry far bigger margins than a single on a main market. So a free bet tied to them is worth less than the same free bet on a plain single.
Since 19 January 2026, UK rules also cap any wagering on a bonus at 10 times and ban offers that mix betting with casino games. The Gambling Commission explains the changes. That makes terms simpler, but it does not remove the costs above.
Free bet value in context
An offer that is worth about £18.55 on average still means you can lose your qualifying stake and see the free bets lose too. Betting is a form of entertainment, not a way to earn, and every bet can lose. Only claim an offer for betting you would enjoy anyway, and only with money you can afford to lose. Also, never open accounts or place bets just to clear an offer.
You can see current deals ranked by estimated value on our offers page. To see how we score them, read how we rate offers.
Related guides
- Price boosts: when are they value?
- Value betting vs matched betting
- Casino bonus value
- Value betting explained
18+ only. Betting should be fun, and every bet can lose. Set a budget you can afford to lose and stick to it. For free, confidential support, visit BeGambleAware.org or call the National Gambling Helpline on 0808 8020 133.