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How Are Thoroughbred Horses’ Ratings Calculated?


Back in January of this year, it was announced that the Juddmonte International Stakes 2020 was crowned Longines World’s Best Race of the Year. It’s a title that course and festival organisers (the Juddmonte Stakes place at the York Ebor Festival, with the 2021 event taking place this week) will accept gladly, as it raises the profile of their events. But the award is also an objective take on something that is ultimately subjective – a great horse race is always in the eye of the beholder.

But how do they arrive at this point? You don’t, for example, see awards for the best football or basketball match of the year. Well, it’s the quality of the field and how they finished that matters. And if you look back at the results from the York Ebor Festival, you’ll see that the Juddmonte Stakes had some of the best-rated horses in the world romping home. Ghaiyyath (1st), Magical (2nd), Lord North (3rd) and Kameko (4th) were the first four home, and their combined ratings added up to the highest-quality race on the planet for 2020.

Frankel has the highest all-time rating

The rating of a racehorse is an intriguing business, and one that does court controversy from time to time. The legendary Frankel, for example, has a rating of 140 – the highest possible rating for a flat racing horse. Frankel’s ranking was adjusted in 2013 after a “historical recalibration” relegated Dancing Brave to 138.

Rankings, of course, are not just there to please owners of elite racehorses; they serve a functional purpose too. For a start, a horse with a higher rating will carry a higher weight than those with lower ratings in certain types of races, particularly handicaps. A good example is the Aintree Grand National, where the handicapper will decide a tiered system of weights for each runner before the race. Not everyone is happy with that system. For instance, Tiger Roll was pulled from the 2021 Grand National because his owner, Michael O’Leary, felt the handicapper gave too much weight to the two-time winner.

The ratings system is complicated in terms of its process, but not difficult to understand in its outcome. The higher the rating, the better the horse (in theory). Arriving at the rating takes into consideration a horse’s wins and placings, but also factors like the racecourse, level of competition, the weights carried, the going (ground), and so on.

The ‘best’ horse does not always win

Of course, bettors will use the rating system too, but perhaps not as religiously as you might think. Other factors come into play. It can vary by season, but some rough data tells us that around 20-22% of race wins are achieved by the horse with the highest rating on the race card, meaning just over one-fifth of all races are won by the horse considered the best in the field.

As we mentioned, there can be some controversy within the ratings system. Consider a trainer who has a racehorse suited to long-distance racing. That trainer could enter the horse into sprint-type races initially, then have a low rating (given lower weights, and thus an advantage) when it switches to greater distances. If you are a bettor, being able to pinpoint when this happens is a formidable weapon.

The above is a simple explanation of how and why racehorses receive ratings. It’s not always a linear process, and sometimes rankings are judged by different committees – but it’s a useful piece of information, even if it does not always tell you the winner of the race.