AUOdds

Dutch Betting Horse Racing: How to Back the Whole Field for a Lock

By the AUOdds team · Updated 11 Oct 2026 · 7 min read

Key takeaways
  • Dutching two or three horses is still a bet, but backing every runner at the best cross-bookmaker prices can lock in a return when the field totals under 100%.
  • Convert each best price to a percentage (1 divided by the odds) and only act when the total sits comfortably below 100%.
  • Rounding stakes to whole dollars changes each outcome's return, so round the favourite's stake up and check the lowest return before betting.
  • Scratchings, late price moves, stake limits and voided bets are the real risks, and any one of them can wipe out a 2% margin.

Dutch betting horse racing usually means splitting a stake across two or three runners so you collect the same amount if any of them wins. The catch is that if another horse wins, you lose the lot. This guide covers a different approach. You back every runner in an Australian race, each at the best fixed price across licensed bookmakers, and only when those prices combine to under 100%. When they do, the right stakes lock in a small return at the prices shown. You'll learn how to collect the best price per runner, check the field total, work out each stake, and handle the three things that break most attempts: scratchings, late price moves and minimum-bet rounding.

In this guide
  1. Why does dutch betting horse racing need the whole field?
  2. How do you collect the best price for every runner?
  3. How do you check the field adds up to under 100%?
  4. How do you stake every runner? A worked example
  5. What happens with scratchings, late price moves and minimum bets?
  6. What are the real risks of a full-field dutching strategy?

Why does dutch betting horse racing need the whole field?

Most dutching guides show you how to back two or three horses so each returns the same amount. That's a sensible dutching strategy when you have a strong view on a short list, but it is still a bet. If a horse you left out wins, every dollar is gone.

A full-field dutch is different. You back every runner still in the race, each at the best fixed price you can find across licensed Australian bookmakers. Because one runner has to win, one of your bets has to pay. The only question is whether the combined prices leave room for a return.

At a single bookmaker they almost never do. Convert each price in a race market to a percentage and the total usually lands well over 100%. That margin is how the book is built. The opening appears when you take the best price for each runner from different bookmakers. Each might be slightly generous on a different horse, and together the best prices can add up to under 100%.

When that happens, staking each runner in the right proportion locks in a return at the prices shown. It won't be large. AUOdds data shows 939 locks over the last 30 days, with a typical lock of around 2.0%. On a $500 field, that is roughly $10.

That's the honest picture: a small, repeatable margin that depends on getting every bet on at the right price. The rest of this guide walks through doing that on an Australian race, step by step.

How do you collect the best price for every runner?

Start with the final field. Check the racecard and note every runner that hasn't been scratched, including any emergencies that could still get a start. Missing one horse breaks the whole lock.

Then go runner by runner and record the best win price on offer. Only use bookmakers licensed in Australia. The ACMA has a guide to checking whether a gambling operator is legal if you're unsure about one.

Keep a simple table:

The time column matters. Racing prices move constantly in the last half hour, and a price you saw five minutes ago may already be gone. Doing this by hand across several apps for a 12-horse field is slow, and slowness is the main enemy.

This is where dutching software earns its place. A good tool pulls the current best price per runner across bookmakers and shows you the field total. When comparing tools, look at how many bookmakers each covers, how many prices it watches and how fresh they are. For reference, AUOdds tracks about 15,000 prices across 9 bookmakers at any moment, with prices typically about 10 seconds old. Whatever you use, confirm each price on the bookmaker's own bet slip before you stake. The bet slip is the only price that counts.

Also check your balances. If the best price for runner 7 is at a bookmaker where you have $12 in your account, either top up first or use the next-best price and recheck the total.

How do you check the field adds up to under 100%?

Each decimal price converts to an implied percentage when you divide 1 by the odds. A $4.00 runner is 25%. A $10.00 runner is 10%. Add the percentages for every runner in the field, using the best price you found for each.

A field at 98.2% returns about $1.018 for every dollar staked, or roughly 1.8%.

A dutch betting calculator does this arithmetic instantly and then splits your stake. It's worth using one even if you understand the maths, because a single typo on a 14-runner field is easy to make and hard to spot. Enter every runner, not just the ones that look interesting. If the calculator lets you set a total stake, use an amount you're comfortable spreading across several bookmakers at once.

Treat a thin margin with caution. A total of 99.6% looks like a lock, but rounding stakes to whole dollars, or one price shortening before you place it, can push it back over 100%. Many people set a personal floor, such as only acting on fields at 98.5% or lower, so there's a buffer for the small things that go wrong.

Finally, recheck the total right before you start placing bets. If any runner's best price has moved, recalculate rather than assuming the margin is still there.

How do you stake every runner? A worked example

Here is a six-runner race with the best price for each horse taken from different bookmakers:

The total is 98.2%, so a lock exists at these prices.

To spread $500, first find the target return: $500 divided by 0.982 is about $509.16. Each stake is that target divided by the runner's odds. Runner 1 gets $195.83, runner 2 gets $115.72, and so on down to $19.58 on runner 6.

Bookmakers want tidy stakes, so round to whole dollars:

Total staked: $501. Whichever horse wins, the return is between $507 and $520, so the result ranges from $6 to $19 at the prices shown.

Notice what rounding did. The exact split would have returned about $9 on every runner. Rounding left one outcome at $6 and another at $19. On a tighter field, rounding down on a short-priced runner can wipe out the margin on that outcome entirely. Round the favourite's stake up, not down, and check the lowest possible return before you place anything.

What happens with scratchings, late price moves and minimum bets?

These three problems cause most broken full-field dutches.

Scratchings. If a horse is scratched before you bet, remove it and recalculate, because the field total changes. If one is scratched after you've placed your bets, your stake on that runner is normally refunded, but fixed-odds win bets on the remaining runners are commonly subject to scratching deductions. A deduction reduces the payout on the winner and can easily cancel a 2% margin. Check each bookmaker's racing rules before you rely on a lock. Where you can, act once late scratchings are likely to be finalised, while still leaving enough time to place every bet before the jump.

Late price moves. You can't place six bets at the same instant. Place first the leg most likely to move, usually the generous price that stands out most against the rest of the market, because others are chasing it too. If a price shortens before you get it on, stop and recalculate with the new price. Sometimes the lock is still there at a smaller margin. Sometimes it's gone and you've already placed some legs, which leaves you holding ordinary bets.

Decide in advance what you'll do in that case. One option is to complete the field at the best remaining prices if the total is still close to 100%. The other is to accept the open position and move on. Choosing under pressure leads to mistakes.

Minimum bets and limits. Stakes on long shots can be small, so check minimum bet sizes. A bookmaker may also accept only part of a larger stake. If a bet is cut, recalculate the remaining legs around what was actually accepted, not the original plan.

What are the real risks of a full-field dutching strategy?

Even a well-run full-field dutch carries risks that the percentage doesn't show.

Keep records of every leg: bookmaker, runner, price, stake and result. They help you spot errors and recognise patterns in what goes wrong. The ATO's ruling on gambling and betting winnings (IT 2655) and its page on gambling winnings set out how the tax office views betting. Get personal advice if your situation is unclear.

Size the field to money you can spread comfortably across several accounts without chasing losses. A 2% margin rewards patience and accuracy, not bigger stakes.

Gambling is for adults 18 and over. If betting stops feeling like a controlled process, BetStop, the National Self-Exclusion Register, lets you exclude yourself from all licensed online and phone wagering providers in Australia. Gambling Help Online offers free, confidential support at any hour.

Frequently asked questions

Is dutching the whole field the same as arbitrage?

It is when the best prices across bookmakers add up to under 100%. Backing every runner at those prices in the right proportions is a form of arbitrage, because one runner must win. Dutching two or three horses is not arbitrage. It's a bet that one of your selections wins, and you lose if any other horse does.

How big is a typical margin on a full-field dutch?

Small. AUOdds data puts the typical lock over the last 30 days at about 2.0%, which is around $10 on a $500 field before rounding. Margins vary by race and change quickly, so check the field total immediately before betting and allow for the effect of rounding stakes to whole dollars.

What if a horse is scratched after I've placed my bets?

Your stake on the scratched runner is normally refunded, but winning fixed-odds bets on the remaining runners may be subject to a scratching deduction. That deduction can reduce or remove your margin. Check each bookmaker's racing rules, and where possible, act once late scratchings are likely to be done.

Do I need dutching software to do this?

Not strictly. You can do the maths with a dutch betting calculator and a spreadsheet. The difficulty is speed: finding the best price for every runner across several bookmakers by hand takes time, and racing prices move quickly near the jump. Price comparison software helps, but always confirm the price on the bookmaker's bet slip.

Sources

  1. Check if a gambling operator is legal, Australian Communications and Media Authority
  2. Taxation Ruling IT 2655: gambling and betting winnings, Australian Taxation Office
  3. Crypto asset prizes and gambling winnings, Australian Taxation Office
  4. BetStop: the National Self-Exclusion Register, Australian Communications and Media Authority

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.