How to calculate a value bet: formula, worked example and common mistakes
A value bet is a bet where the odds pay more than the true chance of the outcome deserves. Checking for one takes a single line: expected value = your probability × decimal odds − 1. If the answer is positive, there's value; if it's negative, there isn't. The formula is easy. The hard part is making sure the probability you feed into it is any good. This guide shows you how to run the numbers and, more importantly, how not to fool yourself with them.
What a value bet actually is
Betting for value doesn't mean backing whoever you think will win. It means betting when the price is wrong. A heavy favourite at 1.30 can have no value at all, while an away side at 4.50 can have plenty. The question is never "who wins?" but "do these odds pay more than this outcome is worth?"
Every price carries an implied probability: 1 divided by the odds. At 2.00 the bookmaker is saying the outcome happens 50% of the time; at 2.50, 40%. If you have solid reasons to believe the outcome happens more often than the price suggests, you may be looking at a value bet.
The value bet formula, step by step
- Estimate the probability. Turn it into a decimal: 55% becomes 0.55.
- Take the decimal odds you can actually bet right now, not the price you saw an hour ago.
- Multiply and subtract 1. 0.55 × 2.10 − 1 = 0.155.
- Read the result. +0.155 means +15.5% expected value per unit staked. For every £100 bet in identical spots, you'd expect to be £15.50 up over the long run.
Another way in is the fair price: 1 divided by your probability. At 55%, fair odds are 1.82. Anything above 1.82 has value on your numbers; anything below doesn't.
| Your probability | Fair odds | Odds offered | Expected value |
|---|---|---|---|
| 50% | 2.00 | 2.10 | +5.0% |
| 50% | 2.00 | 1.90 | −5.0% |
| 40% | 2.50 | 2.75 | +10.0% |
| 65% | 1.54 | 1.45 | −5.8% |
Look at the last row: a pick that lands 65% of the time is still a bad bet at 1.45. A high strike rate won't make you profitable if you keep paying too little for it.
Where the probability comes from: the weak link
The formula is never wrong; the probability you give it often is. There are three usual sources, each with its own trap:
- The market with the margin stripped out. You remove the bookmaker's margin from a very liquid market and use that as your benchmark to hunt for better prices elsewhere. First learn how to calculate a bookmaker's margin, because if you strip it badly you'll see value in what is just noise.
- Your own model. Stats, xG, line-ups, injuries. It works if the model has been tested over hundreds of matches, not the last ten.
- A tipster. If you follow someone, their record tells you whether their picks had value in the past, not whether the next one does.
What never works is a hunch. If you can't explain why your 55% beats the 47.6% baked into the odds, it probably doesn't.
How to tell whether you're really finding value
A value bet can lose. So can ten in a row. That's why a week of results tells you almost nothing. Two checks are far more reliable:
- Closing line value. If you consistently bet at better prices than the closing odds, you're very likely finding value. We cover it in closing line value explained.
- Long-run yield. Over hundreds of logged bets, a positive and stable yield is the final proof. Over 40 bets, it's an anecdote.
Value bets and tipsters: using this to choose who to follow
A good tipster is, at heart, someone who finds value bets more often than the market does. That's why on Tippium every pick is logged before the event with its odds, and you can see each tipster's full record in the verified tipsters list. When you look, don't stop at the strike rate: check the average odds, the yield and whether the posted prices were genuinely available.
And remember that value depends on the price you get. If the tipster posts at 2.10 and the best you can find is 1.95, a good chunk of the edge is gone. Many users follow their picks at Stake, a crypto sportsbook with deep football, tennis and basketball markets; always compare its price with the posted one before you bet.
Why the Stake link won't open or shows an error
If you're in a restricted country such as Spain, France, the UK or the US and you tap the Stake link, the site will usually fail to load, stay blank or show a "not available in your country" message. The link isn't broken and neither is your phone: Stake geo-blocks the countries it doesn't accept, based on the IP address you connect from.
How many people connect with Mullvad, step by step
The route many users take is a VPN, an app that makes your connection appear to come from another country. The most common example is Mullvad. Here's how it works, in plain terms:
- Create a Mullvad account. Go to mullvad.net, click to generate an account number and write it down: there's no email or name, that number is your username and password in one.
- Pay for the time you want. It costs about €5 a month and you can pay by card, PayPal or crypto.
- Install the app. Download it for Windows, Mac, Android or iPhone and log in with your account number.
- Pick a server in a country Stake accepts. In Mullvad's location list, choose a country with servers that isn't on Stake's prohibited jurisdictions list, for example Norway, Finland, Switzerland or Japan. Check that list in the terms first, because it changes.
- Hit "Connect". Wait until the app shows the connection as secure (it turns green).
- Open the Stake link. With the VPN on, use this link to Stake: the site should load normally so you can sign up and deposit.
- Keep the VPN on every time you log in. If you switch it off or change country mid-session, the site will block you again or ask for extra checks.
What Stake's terms say: read this before you deposit
The site loading doesn't mean it's allowed. Clause 14.4 of Stake's terms forbids using a VPN, proxy or false residence details to get around geo-blocking, and under clauses 5.2 and 4.21 Stake can close the account, void bets and withhold the balance, winnings included. On top of that, identity verification (KYC) can ask for an ID and proof of your real address, so the country you live in eventually shows up. If you choose this route, it's at your own risk: only deposit what you're prepared to lose, withdraw often and always check the current terms, because they change.
If you live in a country where Stake is available, you don't need any of this: open Stake here and sign up directly. If you're in a restricted country and don't want that risk, the alternative is a locally licensed bookmaker.
Gamble responsibly: only stake money you can afford to lose and, if betting stops being fun, reach out to a support service in your country.
Value bet FAQs
How much expected value is enough to bet?
It depends on how reliable your estimate is. Using prices from a very liquid market, +2% or +3% is already worth having. With your own lightly tested estimates, demand bigger margins to cover your mistakes.
Does a value bet guarantee a win?
No. It means that, if your probability is right, the expectation is positive in the long run. In the short run, variance rules.
Can I find value in accumulators?
Only if every leg has value on its own, and even then the stacked margin works against you. We go through it in singles vs accumulators.
18+ only. No formula removes the risk of losing: please gamble responsibly.