How are horses’ ages calculated and why is it not the same as humans?

Horses are aged differently to humans and how it works is important for understanding certain aspects of horse racing

Horse racing ages explained


Betting on horse racing isn’t always as simple as choosing your favourite name and sticking money on that pick. As racing punters will tell you, the more you know about the sport the better you are at choosing winners.

And that’s why Paddy Power have created our series of Demystifying Racing guides to help new punters flourish when horse racing betting. Today, we’re looking at why horses’ ages are calculated differently to humans. There’s logic behind it… honest!

How to calculate age of a horse

When you look at a race card you’ll notice the age of each horse, which runs along other stats such as form, silks, headgear and jockey. But a race horse’s age is not the same as a human’s. Whereas we mark our age on our birthdays, horses are grouped together in age depending on what year they were born.

This means each horse, regardless of the day or month of the year they were born, is given a 1 January birthday. So, if a horse running in the 2021 Grand National is eight years old, it was born between 1 January and 31 December 2013.

Horse racing ages explained

Most horses are born between January and April (GETTY)

Why are horse ages important?

Determining the age of a horse is greatly important for the horse racing industry, because there are many races in the UK and Ireland that stipulate age conditions. These allowance or conditions races usually require horses to be of a certain age to run, in order to level out the field.

What’s more, National Hunt races involving horses aged two or three years old are called Juvenile races, while in the Flat season two-year-olds can start their racing career.

But what’s more important for trainers and owners is the development of the horse. One born in the back end of the calendar year may not be as developed as its peers born between January and April. And so they are less likely to win races and have worse racing betting odds until they get to four or five years old, when age advantages level out.

Horse racing race card age

You can easily spot the age of a horse on the Paddy Power race card (PP)

When are race horses born?

Because of how the ageing system works in horse racing – and because the gestation period of a thoroughbred horse is around a year – most horses that are bred for running are born between January and April in the UK and Ireland.

This is to ensure that the horses are as ‘old’ as possible when they begin entering into races.

Remember, a horse born in January is deemed the same age as one born in December of the same year. Those 11 months could make all the difference when they run in Aintree’s Fillies Juvenile Hurdle, or the Champion Bumper at Cheltenham.



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