The 85 percent towing rule explained, a UK caravan guide

Quick answer

The 85 percent rule says your fully loaded caravan (its MTPLM) should not weigh more than 85 percent of your tow car's kerbweight. It is a stability guideline promoted by the Caravan and Motorhome Club, not UK law.

Two things still set the legal limit: the car manufacturer's towing capacity for your specific vehicle (found on the VIN plate), and your driving licence entitlement. Since December 2021, a full Category B car licence allows you to tow a trailer up to 3,500kg MAM, subject to the vehicle's legal limits.

Who this guide is for

• First time tow car buyers trying to pick a sensible caravan weight.
• Experienced towers wondering when it is reasonable to go above 85 percent.
• Anyone confused by adverts that quote "85 percent match" without explaining where the number comes from.

What 85 percent actually means

The figure compares two numbers:

• Kerbweight of the tow car, as quoted by the manufacturer, normally with a full tank of fuel and a nominal driver.
• MTPLM of the caravan, the maximum it is allowed to weigh fully loaded.

If the caravan MTPLM is no more than 85 percent of the car kerbweight, the caravan is unlikely to dominate the car in a stability event. That is the primary reason for the recommendation.

Why it is guidance, not law

The legal towing limits in the UK are set by:

• The car manufacturer's plated towing capacity and Gross Train Weight (GTW) for that exact vehicle specification.
• Your driving licence category (Category B for most, or C1/C for heavier motorhomes).
• Plated axle limits, which must not be exceeded.

You can be inside the 85 percent guideline and still be illegal if you exceed any of those manufacturer or licence limits. You can also be above 85 percent and still legal. The rule is about confidence and stability, not legality.

When 85 percent is the right ceiling

• You have never towed before.
• You drive a relatively light car with a short wheelbase.
• You tour with significant payloads, such as full water tanks or heavy gear.
• You expect to drive in exposed conditions, such as high winds or mountain passes.

When experienced drivers go above 85 percent

Experienced caravanners sometimes tow between 85 and 100 percent of kerbweight, especially with heavy estate cars, large SUVs and pickups. This is a choice some make when:

• The car has a high plated towing capacity well above the loaded caravan weight.
• The noseweight is set correctly (typically within the limit set by the tow ball and car manufacturer).
• Load is packed low and over the axle to aid stability.
• Tyres on both the car and the caravan are within age and load rating limits.

This guide does not certify that any given outfit is safe. The driver is responsible for ensuring the outfit is legally compliant and safe to operate.

Buyer checks before you commit

1. Verify the tow car's kerbweight and plated limits from the V5C or the vehicle's VIN plate.
2. Get the caravan's MTPLM from the manufacturer plate. Note that definitions of Mass in Running Order (MRO/MIRO) can vary by year and manufacturer.
3. Use our caravan towing calculator or towing capacity by registration to help identify legal limits.
4. Confirm your licence entitlement covers the combined weight of your outfit.
5. Plan a visit to a public weighbridge once loaded to verify your actual weights.

What this guide is not

This is buyer guidance only. It is not a safety certification or legal opinion. Overloading or improper matching may affect your insurance cover or claims; you should always check your specific policy or consult your insurer. If you are unsure if your outfit is wider than your car, you must fit suitable towing mirrors to ensure an adequate rear view; failure to do so can result in a fine of up to £1,000 and 3 penalty points.

Related tools and guides

• Caravan towing calculator.
• Check towing capacity by registration.
• Caravan weights explained.
• What is MTPLM.
• Browse used caravans.