What 355 horse racing prices revealed about finding the best odds

By Rhyan Morice | odds-api.net

We compared 355 saved win prices across ten Australian horse races.

The bookmaker with the lowest overround quoted less than a rival on 25 of 71 runners.

That’s 35.2% of the sample. In none of the ten races did the lowest-overround bookmaker match the highest quote on every horse.

A competitive field total can still hide a lower quote on your horse. We checked the whole market, then every runner.

What we compared

We used 355 decimal win prices from Sportsbet, Betr, BetRight, PlayUp and Unibet, covering six Mount Isa races and four Kyneton races.

The saved feed was read at 00:24 UTC on 20 October 2026. All five bookmakers had prices for the same active runners in each selected race.

The saved prices came from odds-api.net’s horse racing odds API, which joins racecards and bookmaker quotes by race and runner.

For each race, we recalculated every bookmaker’s overround, selected the lowest using unrounded figures, then checked its price against the highest quote for each horse.

A joint-highest price counted as a match.

There were 46 matches and 25 runners with a higher price elsewhere.

The 71-runner denominator gives each horse equal weight. We did not average the ten race percentages or use race results to select examples.

The whole field and the individual horse

Overround starts with implied probability.

Divide one by each horse’s decimal odds, add the results for the entire active field and subtract one.

Format that answer as a percentage. A field totalling 127.47% has an overround of 27.47%.

This is a measure of the quoted market. It does not say that the bookmaker will keep 27.47% of stakes.

Actual returns depend on prices accepted, staking and outcomes. Nor does the calculation reveal any horse’s true chance of winning.

Kyneton Race 3 shows why the distinction matters.

PlayUp had the lowest full-field overround, at 27.47%. Betr was next at 29.30%.

Yet PlayUp’s quote was lower than the best available in our saved feed on two of the ten horses.

Horse	Sportsbet	Betr	BetRight	PlayUp	Unibet
Duke Of Oman	41.00	34.00	31.00	34.00	26.00
Western Edge	151.00	126.00	151.00	151.00	91.00
Unannounced	10.00	11.00	12.00	11.00	11.00
Bourne Legacy	1.65	1.70	1.70	1.70	1.70
Ciphered	10.00	10.00	9.00	10.00	10.00
Count Chevalier	14.00	13.00	12.00	14.00	14.00
Merry Chase	3.60	3.50	3.50	3.60	3.60
Velvet Reign	31.00	29.00	26.00	31.00	21.00
The Secret	14.00	14.00	13.00	14.00	14.00
Sarazain	151.00	126.00	151.00	151.00	91.00
Field overround	29.66%	29.30%	31.26%	27.47%	30.78%

Kyneton Race 3 from the saved 20 October feed. Decimal win odds include the returned stake.

Withdrawn runners are excluded; the non-consecutive runner numbers are retained in the workbook.

Duke Of Oman was 34.00 with PlayUp and 41.00 with Sportsbet. Unannounced was 11.00 with PlayUp and 12.00 with BetRight.

PlayUp was highest or joint-highest on the other eight runners, including the shortest-priced horse, Bourne Legacy, at 1.70.

BetRight had the highest overround in this race, at 31.26%. It also had the outright highest quote on Unannounced.

Its shorter prices elsewhere in the field pushed up the total. That didn’t stop it offering the highest quote on this horse.

Repeat the comparison in a spreadsheet

The accompanying workbook includes all 71 runners, a summary of all ten races and a worked Kyneton Race 3 sheet.

The worked sheet uses the same layout as the table: horses in column A and the five bookmakers in columns B to F. The ten horses occupy rows 2 to 11.

First, calculate each horse’s implied probability. In B16 enter =1/B2, copy across to F16, then fill down to row 25.

Format these cells as percentages. These are implied probabilities from the quotes, not independently estimated win probabilities.

Next, enter =SUM(B16:B25)-1 in B13 and copy across to F13.

These five cells hold the field overrounds. Displaying two decimal places makes them readable, but keep the full values for comparisons.

For individual prices, enter =MAX(B2:F2) in G2 and fill down to G11.

In H2, =INDEX(B2:F2,1,MATCH(MIN($B$13:$F$13),$B$13:$F$13,0)) returns that horse’s quote from the lowest-overround bookmaker.

Fill that down too. In I2, =IF(H2<G2,1,0) marks a lower quote; copying it down and summing I2:I11 gives two.

The lookup selects the first column if two field overrounds are exactly tied. None of the ten saved races had an exact tie.

For a new race with tied minima, check every tied bookmaker rather than treating the column order as a winner.

If you repeat this with another race, include every active runner and update the row ranges to match the field.

Convert fractional prices to decimal by dividing the numerator by the denominator, then adding one. For example, 10/1 becomes 11.00.

Why rounding deserves a separate check

Two races had extremely close lowest overrounds.

At Mount Isa Race 1, Sportsbet and BetRight differed by about 0.0029 percentage points.

At Kyneton Race 1, Sportsbet and Betr differed by about 0.0016 points. Both pairs look tied when displayed to two decimal places.

We therefore also grouped every bookmaker within 0.05 percentage points of the lowest overround.

For each horse, we took the highest quote within that group. Even with this more generous comparison, 18 of 71 runners still had a higher quote outside the group.

The workbook preserves the exact-ranking result and labels this sensitivity check separately.

What this sample can establish

The result describes one saved feed observation across two Australian meetings.

Source metadata was 10.7–24.3 minutes older than capture and does not establish when each bookmaker last changed its price.

The five price columns should therefore be read as saved feed quotes, not verified simultaneous offers on bookmaker websites.

We selected races by complete-field bookmaker coverage, then bookmaker count and scheduled start, without using price gaps, leaders or results.

Scratched runners were excluded and verified Mount Isa and Mt Isa aliases were counted once. Betfair Exchange was excluded from this fixed-odds comparison.

We did not test stake acceptance, subsequent movement, closing prices or profits.

The sample does not rank British bookmakers, and it cannot settle comparisons involving each-way terms or Best Odds Guaranteed.

Those are different offers from the straight win quotes analysed here.

Readers building their own comparison can use the racing API to connect race discovery, runner prices and timestamps.

Preserve the time of each quote and keep withdrawn runners separate from missing prices before calculating a field total.

Use the field overround for context. Then compare the price on the horse itself.