How Odds Comparison Works for Irish Punters

How odds comparison works (and how to actually use an odds checker)

The same horse can be 5/1 with one bookmaker and 11/2 with another at the same moment, and neither price is wrong. On a €20 bet, that gap is €10 for exactly the same result.

An odds checker exists to find that gap. It gathers the published prices for a market, lines them up in a grid and shows you which firm is biggest. That is the whole product, and it is more useful to a casual punter than most of what gets sold to them.

Here is what a comparison table is actually doing, why the prices differ in the first place, and the handful of things the grid does not show you.

The short version

• It is a price list, not a tip. An odds checker tells you where a bet is cheapest to strike. It says nothing about what will win.

• Prices differ for three reasons: traders disagree, firms hold different liabilities, and every bookmaker sets its own margin.

• The margin is the bit worth understanding. Add up the chances implied by a full set of prices and they come to more than 100%. The overshoot is the bookmaker's cut.

• It only pays off if you can act on it. A comparison table you can only use in one app is entertainment.

• The grid does not show the terms. Deductions for withdrawn runners, each-way places, maximum payouts and best odds guaranteed all sit outside the price, and any of them can be worth more than the price.

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What an odds checker actually does

Every bookmaker publishes its prices. A comparison site collects them, market by market, and lays them out in a grid: one row per selection, one column per firm, with the biggest price in each row marked out. There is no model underneath it and no prediction of any kind.

It does two jobs. The obvious one is finding the biggest number before you strike the bet. The quieter one is showing you the shape of a market: a firm well out of line with everyone else on a horse has usually not caught up with a move rather than spotted something.

One caveat. A grid is a snapshot of whenever it last pulled the data, so on a busy Saturday it can run a few minutes behind. It is a steer on where to go, not a promise of what you get when you land.

Why the same horse is 5/1 in one place and 11/2 in another

Three things, in order of importance.

Opinion. Someone has to decide what a horse's chance is worth, and reasonable people disagree. A firm that rates a runner worse than the rest will happily lay it at a bigger price.

Position. A bookmaker is managing bets it has already taken. Take a pile of money for one runner and the sensible move is to shorten it and push the others out. Prices shortening and drifting through the day, what the racing press calls market movers, are mostly weight of money rather than anything anyone knows.

Margin. Every price has the bookmaker's cut built into it, and how big that cut is comes down to commercial choice. This is the one worth spending a minute on, because it is what a comparison grid is really measuring.

The overround, in one worked example

Turn a price into an implied chance and it gets a lot clearer. A price of 5/1, or 6.00 in decimals, implies a 16.67% chance. 11/2, or 6.50, implies 15.38%. Bigger price, smaller implied chance, more back if it lands.

Do that for every outcome in a market and add the percentages up. In a perfectly fair market they would total 100%. In a real one they always total more, and the excess is the margin. The trade calls it the overround.

Take a made-up football match with three outcomes priced at 2.00, 3.50 and 4.00. Those imply 50%, 28.57% and 25%, which totals 103.57%. The 3.57% on top is the bookmaker's edge. Now the same match at a tighter-fisted firm: 1.91, 3.30 and 3.75, which totals 109.35%.

Put it in euro. Stake €100 across all three outcomes so you get the same amount back whichever way the match goes, and the first book returns €96.55. The second returns €91.45. That is not a betting strategy, it is just the cleanest way to see the cut.

The more outcomes in a market, the more room the margin has to hide, which is why a twenty-runner handicap at Fairyhouse is where comparing prices earns its keep.

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What the gap is actually worth

A €20 bet at 5/1 returns €120. The same €20 at 11/2 returns €130. Same horse, same race, same result, a tenner between them.

As a share of your profit that is 10% more for doing nothing except striking the bet in a different app. Take the best price available rather than the first one you see, and that difference lands on every winner you have.

Be straight about what that is and is not, though. Shopping around does not change how often you are right, only what being right pays. And the margin is still in there: even the biggest price on the grid has the bookmaker's cut inside it. Comparing narrows the house's edge. Nothing removes it.

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Best odds guaranteed, and where it fits

Best odds guaranteed, BOG in the shorthand, means that if you take an early price and the starting price turns out bigger, you get paid at the bigger one. It puts a floor under an early price, which changes what you are comparing: a choice between two similar prices can come down to whose concession is better rather than whose number is bigger.

Three things worth knowing about it.

• It is a concession, not a rule. No Irish law requires it. Each firm writes its own terms and limits it by sport, market, bet type and the window in which it applies.

• It is not universal and it is not permanent. It tends to sit on horse racing and, at some firms, greyhound racing. It can be narrowed, withdrawn or pulled from individual accounts, and firms do exactly that.

• The rule book is where you check it. Not a comparison grid and not a third party describing it. The operator's own published terms are the only version that binds anyone.

Worth knowing where the law sits. The restrictions on inducements in the Gambling Regulation Act 2024 have not commenced, so concessions and promotions of this kind are lawful in Ireland today. When they do start, what operators may offer changes, and this is one of the areas most likely to look different afterwards.

The price you see is not always the price you get

This is the part a grid cannot show you, and it is where the real money hides.

A withdrawn runner. If a horse comes out after you have taken a price, your winnings are cut by a deduction sized on the withdrawn horse's price. Horse Racing Ireland publishes the scale applied at Irish racecourses: a withdrawal at evens takes 45c in the euro off winnings, one priced 10/1 to 14/1 takes 5c, and anything longer than 14/1 takes nothing at all. Where two or more come out, HRI caps the total on course at 75c in the euro. Online bookmakers apply their own version of the same industry scale under their own rules, so that is where to look for the online figures.

What it does in practice: €20 at 5/1 is €100 of profit. A withdrawal at evens takes 45c in the euro off that, leaving €55 profit and €75 back in total. The price you took never changed. The payout did.

Ante-post against non-runner no bet. Ante-post prices are bigger because your stake is gone if the horse does not run. Where a firm prices a race non-runner no bet, the stake comes back instead. Two different products, and a grid will show them in the same row, so the bigger number is not automatically the better bet.

Each-way terms. Grids show the win price. In golf especially, the number of places paid and the fraction of the odds paid on them vary a lot between firms, and around a tournament like the Irish Open that difference is often worth more than the win price. Same story in big-field handicaps.

The price simply moving. Between the grid loading and you confirming, the price can go. Most apps ask whether you accept the new one. Read that prompt rather than tapping through it, because the price was the point.

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Exchanges, on-course prices and the 2% everyone gets wrong

A comparison table sometimes carries betting exchange prices alongside bookmaker prices, and they are not like for like. An exchange price is quoted before commission, so it is not what you take home. The exchange earns on commission rather than on a margin baked into the price, which is why its prices look bigger.

The duty works differently too, and this is where the most repeated myth in Irish betting comes from. Revenue charges betting duty at 2% on bets taken over the counter and 2% on remote bets, nothing at all on on-course or tote bets, and 25% on the commission a remote betting intermediary charges. Every one of those is a bill for the operator. None of them is a deduction from your winnings, and there is no 2% tax on your winnings.

The nil rate on course is one reason the boards at Galway or Leopardstown look different from the app in your pocket. Different market, different costs, rather than the same market with better prices.

Two or three accounts is where the value actually is

A comparison table you can only act on in one place is not much of a tool. It works only if you can strike the bet wherever the price is biggest, which means accounts with more than one firm. Two or three is plenty; beyond that you are managing accounts rather than betting.

Three things worth being straight about first.

• Bookmakers watch this. Consistently taking the biggest price is exactly the pattern that gets an account restricted to small stakes or closed. That is the firm's commercial right, it happens routinely, and nobody explains it to you at the time.

• Every account is a full sign-up now. Since 1 July 2026 a licensed remote operator has to verify who you are and how old you are before you can register: photo identification, proof of address, and a bank, building society or credit union statement from the last six months.

• This is about price, not about collecting offers. Opening accounts to hoover up sign-up bonuses is a different game with its own terms attached, and not what a comparison grid is for.

One thing to weigh before the fourth account. More accounts means more places money can go, and it makes stepping back harder if you ever want to. Ireland has no national self-exclusion register in operation yet, so self-exclusion is arranged with each operator separately, one at a time. A longer list is a longer job.

What a comparison site is not

Worth knowing what you are looking at, and this applies to us as much as to anyone else.

Comparison sites are commercial. They are funded by commission from the firms they list, so the list is rarely every bookmaker in the market and the running order is not neutral by default. That does not make the prices wrong: a price is a fact and it takes ten seconds to check against the bookmaker's own site. But bring the same eye to the coverage and the ordering that you would bring to any advertising.

They are also not regulated in Ireland. The GRAI licenses gambling operators, and since 1 July 2026 a bookmaker taking bets from people in Ireland has needed a remote betting licence. The Authority has said operating without one is a criminal offence and that it has begun identifying unlicensed operators. Business-to-business licensing, which covers the supply and advertising of gambling products and gambling-related services, has not opened: the GRAI's phasing puts it alongside gaming and lotteries across 2027 and 2028.

So the practical check is on the bookmaker, not the table. Before opening an account with a firm you do not recognise from a comparison grid, confirm it holds a GRAI betting licence and that the licence covers what you are actually doing on the site.

Frequently asked questions

What does an odds checker actually do?

It collects the prices bookmakers publish for a market and lays them in a grid so you can see which firm is biggest on each selection. It makes no prediction and does not tell you what will win. It tells you where a bet is cheapest to strike.

What does best odds guaranteed mean?

That if you take an early price and the starting price is bigger, you are paid at the bigger one. It is an operator concession rather than an Irish legal requirement, usually limited to horse racing and sometimes greyhounds, and each firm sets and can change its own terms.

Do I pay tax on betting winnings in Ireland?

No. Winnings are not taxed for players. The 2% betting duty is charged to the bookmaker on bets it takes, remote or over the counter, and Revenue charges nothing on on-course or tote bets. A remote betting intermediary pays 25% on the commission it charges. None of it comes out of your winnings.

Why were my winnings cut after a horse was withdrawn?

A deduction applies to bets struck before the withdrawal, sized on the withdrawn horse's price. On the scale Horse Racing Ireland applies at Irish racecourses, a withdrawal at evens takes 45c in the euro off winnings and anything longer than 14/1 takes nothing. Online firms apply their own version of the same scale under their own rules.

Can taking the best price get my account restricted?

Yes, and it does. Bookmakers monitor accounts and may cut stakes or close one that consistently takes the biggest price. It is a commercial decision rather than a rule, and no Irish requirement obliges a firm to keep taking your bets.

Are odds comparison sites regulated in Ireland?

Not as things stand. They are commercial publishers funded by commission from the firms they list, and business-to-business licensing under the Gambling Regulation Act 2024 has not opened, with applications expected across 2027 and 2028. The bookmaker is the thing to check: remote betting operators have needed a GRAI licence since 1 July 2026.

Safer gambling: a better price is a reason to be choosy about where you bet, never a reason to bet more often. If gambling is causing difficulty for you or someone you know, the National Gambling Helpline is free and confidential on 1800 936 725, 24 hours a day.