Sure Bet Explained: What Australians Call a Lock
- In European betting software, a 'sure bet' means an arbitrage that covers every outcome, not a confident tip.
- 'Sure win' tips back a single outcome and can lose like any other bet.
- Australians usually call an arbitrage a lock, found in pre-match and pre-race markets at licensed Australian bookmakers.
- A lock locks in a small return at the prices shown, and recent typical locks have sat around 1.5%.
- Moving prices, stake limits, voided bets and simple mistakes can all break a lock, so the word 'sure' should never be taken literally.
Sure bet explained simply: in European betting software, a 'sure bet' is an arbitrage. That means a set of prices across different bookmakers where backing every outcome returns more than you staked at the prices shown. In Australia, most people call the same thing a lock. The confusion starts because tipping pages use 'sure bet' and 'sure win' for single selections that can lose like any other punt. This guide separates the two meanings and shows how the Australian lock works with a realistic tennis example. It also lists the risks that the word 'sure' tends to hide. By the end, you will be able to look at any 'sure bet' claim and tell in seconds whether it is maths or marketing.
Sure bet explained: what does the term really mean?
In European betting software, 'sure bet' (often written as one word, surebet) is simply another name for an arbitrage bet. It describes a set of prices across different bookmakers where backing every possible outcome, in the right proportions, returns more than the total staked at the prices shown.
The word 'sure' refers to the maths, not the match. Nobody knows who will win. What the software has spotted is that the bookmakers disagree enough that the combined implied probability of all outcomes falls below 100%.
The term grew up in Europe, where comparison tools scan dozens of bookmakers across many countries. Tools there label each find a 'surebet' and show it as a percentage, such as 1.8% or 2.4%. That percentage is the margin you would lock in if every leg were placed at the displayed price.
When a European forum user says 'I found a sure bet on the tennis', they usually mean:
- Two or more bookmakers are offering prices that together cover every outcome of one event
- The implied probabilities add up to less than 100%
- Splitting stakes correctly returns about the same amount whichever side wins
That is a narrow, technical meaning. It has nothing to do with confidence in a team, inside information or a strong form guide. A sure bet in this sense can involve backing a big outsider, because you are also backing the favourite at another bookmaker.
The trouble is that tipsters use the same two words very differently, and that is where most of the confusion starts.
Sure bets meaning: why aren't 'sure win' tips the same thing?
Search for sure bets meaning and you will find two worlds mixed together. One is arbitrage software. The other is tipping pages offering 'sure bets, sure win' selections for tonight's games.
A tip is a single opinion. Someone thinks one outcome is likely and suggests you back it. If that outcome loses, your stake is gone. Confident wording does not change that. Phrases like 'sure win' describe the tipster's marketing, not the bet.
Here is a quick way to tell them apart:
- Number of bets: an arb covers every outcome, usually across two or three bookmakers. A tip backs one outcome.
- What it depends on: an arb depends on prices. A tip depends on the result.
- How it is shown: an arb comes with exact stakes for each leg and a percentage return. A tip comes with a selection and perhaps a confidence rating.
- What happens if the favourite loses: with an arb, the other leg pays. With a tip, you lose your stake.
- Shelf life: an arb can disappear within minutes as prices adjust. A tip can sit on a page all day.
If a page uses 'sure bet' but only names one team, it is a tip using borrowed language. If it lists every outcome with a stake beside each, it is describing an arbitrage.
Neither label tells you whether the person behind it is trustworthy. But recognising which one you are looking at stops you treating a punt as if it were a calculated position.
Why do Australians call a sure bet a lock?
In Australia, punters and arbers more often say 'lock' or 'arb' than 'sure bet'. The idea is identical. The prices across bookmakers let you lock in a return before the event starts. The word suits the action, because once every leg is on at the expected prices, the result no longer changes what you get back.
The local market shapes how locks appear. Australians can only bet online with licensed Australian bookmakers. The Australian Communications and Media Authority explains how to check whether a gambling operator is legal (ACMA-LEGAL). That means the pool of prices is smaller than the one European software scans. Online in-play sports betting isn't offered to Australians, so locks here are found in pre-match and pre-race markets.
Even with a smaller pool, bookmakers disagree often. AUOdds data shows 3,587 locks over the last 30 days and 1,032 in the last seven. Those locks were drawn from about 15,000 prices across 9 bookmakers, refreshed roughly every 10 seconds. The typical lock over the 30-day period was around 1.5%.
That figure is worth sitting with. A lock is not a big win. It is a small edge that comes from prices, and it rewards accuracy and speed more than bold calls.
Common Australian terms you will see alongside 'lock':
- Arb or arb %: the margin, the same as a European surebet percentage
- Legs: each individual bet that makes up the lock
- Dutching and middles: related strategies with their own rules and risks, not the same thing as a standard lock
What does a lock look like with real numbers?
Take a pre-match tennis match. Bookmaker A offers Player 1 at 2.10. Bookmaker B offers Player 2 at 1.98.
Convert each price to an implied probability by dividing 1 by the odds:
- 1 ÷ 2.10 = 0.4762 (47.62%)
- 1 ÷ 1.98 = 0.5051 (50.51%)
Together they make 98.13%. Because that is under 100%, the prices form a lock of about 1.9%.
Now split a $500 total so each leg returns the same amount. Each stake is the total multiplied by that leg's share of 98.13%:
- Player 1 at Bookmaker A: $500 × 0.4762 ÷ 0.9813 = $242.65
- Player 2 at Bookmaker B: $500 × 0.5051 ÷ 0.9813 = $257.35
Check the returns:
- If Player 1 wins: $242.65 × 2.10 = $509.57
- If Player 2 wins: $257.35 × 1.98 = $509.55
Either way, you get back about $509.56 on $500 staked. That is a return of roughly $9.56 at the prices shown, with a few cents' difference due to rounding.
Compare that with a tip calling Player 1 a 'sure win' at 2.10. Put $500 on it and you get $1,050 back if the tip is right, and nothing if it is wrong. The tip has a bigger upside and a real chance of losing the lot. The lock has a small upside that depends on both bets standing at those exact prices.
This is the whole difference in one picture. A lock covers every outcome. A tip picks one.
What risks hide behind the word 'sure'?
The maths of a lock holds only if everything goes to plan. In practice, several things can break it, and each one is worth planning for.
- Prices move. You place the first leg at 2.10, but by the time you reach the second bookmaker, the 1.98 has shortened to 1.90. The lock may now be gone, or it may have turned into a small loss. Placing the less stable price first and working quickly both help.
- Stakes get limited. A bookmaker may accept only part of your stake on one leg, leaving you unbalanced. Check the accepted amount before placing the other side.
- Bets can be voided. Obvious pricing errors can be cancelled under a bookmaker's terms. If one leg is voided while the other stands, you are left holding an ordinary single bet.
- Rules differ. Tennis retirement rules and the way extra time counts in soccer can vary between bookmakers. If two bookmakers settle the same event differently, one leg may lose while the other is voided.
- Mistakes happen. It is easy to pick the wrong player, the wrong market or mistype a stake. Under time pressure, small errors are common.
None of these risks appear in a European 'surebet' label or an Australian 'lock' alert. The percentage tells you what the prices offer, not whether you will capture it.
A sensible approach is to read each bookmaker's settlement rules for the sports you use. Keep a record of every lock, and review the ones that went wrong. Over time, your records will show your real return, and that is the number that matters.
How should you read 'sure bet' claims before acting?
Whether you see 'sure bet', 'surebet', 'lock' or 'sure win', run the claim through the same quick checks.
- Does it list every outcome? If not, it is a tip, whatever it is called.
- Are the bookmakers licensed in Australia? Check any unfamiliar name using ACMA's guidance on legal operators (ACMA-LEGAL).
- Is it pre-match or pre-race? Online in-play sports betting isn't available to Australians, so a service pushing live sports locks isn't built for local punters.
- Are exact stakes given? A real lock comes with a stake for each leg, worked out for a chosen total.
- How old are the prices? A lock found a few minutes ago may already be gone. Fresh prices matter more than a high percentage.
- Is the percentage believable? Most genuine locks are small. A steady stream of 10% 'sure bets' deserves suspicion.
- Does the wording promise money? Anyone promising a win on every bet is ignoring moving prices, limits and voids.
AUOdds alerts follow the lock model. Each alert shows every outcome, the bookmaker for each leg and the stake for each, so you can check the numbers yourself before deciding.
Whatever you decide, keep betting in proportion. Gambling is for adults 18 and over, and it should only involve money you can afford to lose. If betting stops being enjoyable or starts costing more than you planned, BetStop can help. It is the National Self-Exclusion Register, and it lets you exclude yourself from licensed Australian online and phone betting providers (BETSTOP, ACMA-BETSTOP). Free, confidential support is available through Gambling Help Online, and the Department of Social Services has further information on gambling support (DSS-GAMBLING).
Frequently asked questions
Is a sure bet the same as an arb?
Yes, in the software sense. European tools use 'sure bet' or 'surebet' for exactly what Australians call an arb or a lock. It is a set of prices across bookmakers where backing every outcome returns more than the total staked at the prices shown. The word 'sure' describes the maths of the prices, not the result of the event.
Are 'sure bets sure win' tips worth following?
Treat them as ordinary tips. A 'sure win' selection backs one outcome, so if that outcome loses, you lose your stake. The wording is marketing rather than a description of the bet. If a tip appeals to you, judge it like any other opinion, and only stake money you can comfortably afford to lose.
Why are locks usually such small percentages?
Bookmakers build a margin into their prices, so the prices only cross under 100% when they disagree by a reasonable amount. Those gaps tend to be narrow and close quickly as prices adjust. Recent typical locks have sat around 1.5%. A much higher figure is possible but rare, and it is often a sign of a pricing error that may be voided.
Can I find locks during a live game in Australia?
Not through online betting. Online in-play sports betting isn't offered to Australians, so locks with licensed Australian bookmakers are found in pre-match and pre-race markets. Any service suggesting live online sports locks for Australian accounts is not set up for the local rules, and you should treat it with caution.
Sources
- Check if a gambling operator is legal, Australian Communications and Media Authority
- BetStop, Australian Government
- BetStop: the National Self-Exclusion Register, Australian Communications and Media Authority
- Gambling, Department of Social Services
More guides
18+ only. Betting involves risk, and prices and limits can change before you place a bet. If gambling isn't fun any more, Gambling Help Online (1800 858 858) is free and confidential, and BetStop lets you exclude yourself from every licensed Australian bookmaker.