Towing Capacity Calculator
Works out the real towing limit for a loaded vehicle from the ratings on its plate. The brochure figure assumes an empty vehicle; this one does not.
The lowest of the three limits below, loaded.
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
The formula
max trailer = min(tow rating, GCWR − loaded vehicle, (GVWR − loaded vehicle) ÷ tongue fraction)
Three limits apply at once and the lowest wins. The tow rating is the drivetrain and chassis; GCWR is the whole combination; and GVWR bites through the tongue weight, because that part of the trailer is carried by the vehicle. Loading the vehicle reduces the first two allowances directly.
What to watch out for
The ratings and what each one protects:
- Tow rating — the drivetrain, cooling and brakes.
- GCWR — the combination. Everything in the car comes off the trailer allowance, kilo for kilo.
- GVWR and the rear axle — the tongue weight is carried by the vehicle, and with a heavy trailer it can be a few hundred kilos on the rear axle alone.
- Hitch class — the receiver has its own rating, often lower than the vehicle’s.
Legal limits vary by country — licence categories, the 3,500 kg combination limit for a standard licence in much of Europe, trailer brake requirements — and sit on top of all this.
Frequently Asked Questions
How much can my car tow?
The lowest of the tow rating, GCWR minus the loaded vehicle, and the GVWR headroom divided by the tongue fraction. A 3,500 kg rated vehicle weighing 2,460 kg loaded on a 6,500 kg GCWR can tow 3,500 kg by rating but only 4,040 by GCWR — so 3,500 — while at 10% tongue weight the GVWR allows 5,400. The rating binds.
Does passenger weight reduce towing capacity?
Yes, directly. Every kilogram in the vehicle comes off the GCWR allowance and uses up GVWR headroom that the tongue weight needs. Four adults and luggage can take 400 kg off a trailer allowance.
What is the difference between GVWR and GCWR?
GVWR is the maximum the vehicle alone may weigh loaded. GCWR is the maximum for the vehicle and trailer together. Both are on the plate, and the trailer has to fit under both.