Understanding Horsebox Weights and Payloads

A horsebox's payload is one of the most important things to consider when buying a horsebox. However, it's often misunderstood or overlooked. It's vital to check that any horsebox you buy will have enough payload for your needs. Overloading a horsebox is illegal, unsafe, and can leave you with heavy fines and penalities (not to mention putting your horse at risk).

What's the difference between tonnage and payload?

A vehicle's gross weight (often called tonnage) and it's payload are not the same. Whilst a vehicle's tonnage refers to the maximum allowed weight of the vehicle plus its load, the payload is how much weight the vehicle can carry on top of it's own weight. In simple terms:

• Unladen Weight (kerb weight): what the horsebox weighs empty, with no horses or cargo (but including necessary fluids, and maybe a driver).
• Gross Vehicle Weight (GWV) (aka tonnage): the maximum legal weight of the loaded horsebox (e.g. 3.5t/3500kg).
• Payload: the difference between GWV and the unladen weight. This is the carrying capactiy for your horses and equipment.

When a horsebox is described as 3.5t, 4.5t, 7.5t, etc., that is not the weight of the empty vehicle - it’s the max gross weight limit. If the unladen weight was equal to the maximum weight, then you'd have zero payload, meaning you couldn't legally carry anything.

Why are there limits on payload?

A permitted total weight is calculated to ensure the vehicle operates within it's limits. Overloading any vehicle is dangerous, and can cause braking and stability issues. Manufacturers of vans aim to keep the unladen weight of a vehicle low, so that the payload is as large as posssible. This is paritcularly important with 3.5t horseboxes, where payload is at a premium.

The DVSA (previously VOSA) do spot-checks and can prohibit you from traveling if you're overweight.

Finding the payload of your horsebox

When buying or using a horsebox, it's essential to verify the actual payload rather than relying on manufacturer brochures or verbal assurances. Payload is the difference between your horsebox’s gross weight and its unladen weight – the latter should be confirmed with recent evidence, such as a weighbridge ticket showing the vehicle when empty but fully fuelled. The most accurate approach is to weigh the horsebox yourself and subtract that figure from the maximum gross weight. You can find your closest weighbridge online.

For a standard 3.5t horsebox, this typically leaves you with around 1,000kg of payload, which is usually suitable for one large horse or two smaller ponies, along with tack, fuel, and equipment. Be cautious if someone claims a 3.5t horsebox can carry two large horses - this often exceeds the legal payload limit and could result in fines, safety risks, or insurance issues.

What's the payload of 3.5 tonne horsebox?

The payload of a 3.5t horsebox can vary widely depending on its build and materials. As a rule of thumb, many 3.5 tonne horseboxes (especially those with a full coachbuilt body and living area) have a payload in the range of 1,000 kg (1.0 tonne), give or take. Simpler van-style conversions (where the horsebox is built by modifying a cargo van like a Renault Master or Ford Transit) tend to be lighter, often having payloads around 1,200 kg (1.2 tonnes). On the other hand, a more elaborate coachbuilt 3.5t with a lot of extras (such as living) or thicker construction might only offer around 600–800 kg payload.

Because of the variability, it's important that you have a payload certificate for your horsebox (post conversion).

Can a 3.5 tonne horsebox carry two horses?

Whether a horsebox can carry two horses depends on the size of the horses and the specific horsebox's payload. However, often a 3.5 tonne horsebox cannot safely carry two large horses. Most 3.5t boxes have a payload around 1000-1200kg. Whilst a single 16.2hh warmblood can weight 600-700kg alone; two large horses can easily weigh 1200-1400kg combined - and that's not including tack, hay, water, and people. In this case, the payload of a 3.5 tonne lorry would clearly be exceeded.

Often, two small horses or ponies might come in under the permitted payload of a 3.5 tonne lorry. In contrast, two big hunters or a heavy horse and a cob would likely exceed the payload. Even if the weight is just about acceptable, consider space and comfort: the stalls in a 3.5t are quite snug for two large horses and handling might be compromised if the vehicle is at its absolute max weight.

Some small van-type 3.5T horseboxes (with very minimal bodies) advertise that they can carry two horses because they managed to maximise payload​. For instance, a lightweight van conversion with ~1.2t payload could technically carry two horses of about 500–600 kg each (plus minimal gear). But this typically only adds up for smaller horses or ponies. If you have two larger horses to transport regularly, you really should look at an uprated chassis (4.5T or 7.5T) for safety’s sake.

What payload do I need for two horses?

For two horses, think in the ballpark of at least 1.3 to 1.5 tonnes of payload as a comfortable minimum, especially if they are decent-sized. Let’s break it down: say each horse is ~600 kg (which is a typical weight for a 16-16.2hh horse in moderate condition; heavier breeds could be more). Two of those is 1,200 kg. Add two saddles and bridles (~20 kg), two people (~150 kg combined, depending), water, hay, buckets, grooming kits (could easily be another 50+ kg), and you’re quickly around 1,400+ kg. You also want a safety margin – you don’t want to be at 3,499 kg out of 3,500, because even a slight miscalculation means you’re overweight. Having about 1.5t payload gives you that buffer.

This is why many people opt for a 7.5t lorry for two horses, as those typically have 2+ tonne payloads and plenty of space. However, if you prefer a smaller box, a 4.5t might suffice.

Just because a horsebox is advertised as a "2-horse" or even "3-horse" box doesn’t mean it can legally carry that many if weight is considered. Always check the actual payload. As a precaution, when viewing a horsebox, ask the seller for the current unladen weight certificate or have it weighed. If they don’t have a recent weight, you can request to drive it to a public weighbridge (many sellers will accommodate this if they’re confident in their vehicle). Knowing the unladen weight lets you compute exactly what payload you have for your two horses.

In short, for two medium-sized horses, look for at least ~1.3t payload (more is better). That usually means a vehicle heavier than 3.5t unless it’s a super lightweight build.

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Disclaimer: This blog post is intended for informational purposes only and does not constitute financial or legal advice. Always consult with a professional insurance broker or advisor to find the best policy for your specific needs.