Caravan Towing Calculator: Worked Example With Stated Ratings

If you are working out caravan towing calculator, the trailer type changes the maths. Different trailers load the hitch differently, carry their weight differently and need different checks before you set off. This page covers the method that applies to every trailer — the lowest-of-three rule, the GVWR and GCWR limits and the tongue-weight check — and then works through the details that matter for this kind of trailer.

Never exceed your vehicle's GVWR, GCWR or payload. Check the owner's manual and the door-jamb sticker for the ratings that apply to your exact vehicle, and treat every figure on this page as a worked example unless it comes from your own vehicle's plates.

caravan towing calculator: The method: the lowest of three ratings

Three ratings decide what you may tow, and the answer is the smallest of them: the vehicle's tow rating, the tow-bar rating and the trailer's ATM — the aggregate trailer mass, the most the loaded trailer is rated to weigh. Here the worked example uses 1,800 kg for the vehicle, 2,500 kg for the tow bar and 2,200 kg for the trailer ATM, which makes the towing capacity 1,800 kg. Those numbers are examples, not ratings for any real vehicle: read the three figures off your own manual and plates and the same step gives your answer. Each rating guards a different part of the rig — the vehicle's engine, transmission, brakes and cooling; the tow bar and its mounting; the trailer's axles, tyres and brakes — so the weakest link sets the limit.

The tow rating alone is not the whole answer. GVWR caps the loaded vehicle, GCWR caps the vehicle and trailer together, and payload — GVWR minus kerb weight — caps what the vehicle itself may carry, including the tongue weight pressing down on the hitch. A heavy trailer therefore eats into the passengers and cargo you can carry, and a combination can be inside the tow rating yet still overloaded on GCWR or payload. Every limit has to pass at once, and the numbers for your exact vehicle are in the owner's manual and on the door-jamb sticker.

caravan towing calculator: Where to find your ratings

Four plates and documents carry the whole answer. The owner's manual lists tow ratings by engine, axle ratio and configuration and states GVWR and GCWR. The driver's door-jamb sticker gives the GVWR and payload for your exact vehicle as built. The tow-bar rating plate sits on the bar or by the receiver. The trailer's compliance plate shows its ATM and tare weight. Read all four, and if two sources disagree, use the lower figure and ask a dealer to confirm for your VIN. Ratings shift with engine, axle ratio, cab, bed length and tow package, so a figure for a different configuration — or one copied from a forum — is not a substitute.

Worked example: the three ratings and the payload check for caravan towing calculator

Take a 1,200 kg loaded trailer as the example. The vehicle's tow rating is 1,800 kg, the tow-bar rating is 2,500 kg and the trailer ATM is 2,200 kg. The towing capacity is the lowest of the three: 1,800 kg. The trailer's tongue weight at 10 to 15 percent is 120 to 180 kg, and the middle of that range — about 150 kg — is a good target. With an example payload of 800 kg, the tongue weight leaves 650 kg for passengers and cargo. If the passengers and luggage weigh more than that, the combination is overloaded even though the trailer is inside the tow rating, and something has to come off — either the trailer load or the vehicle load. That is the whole check in one paragraph: lowest of three, then tongue weight, then payload, then GCWR. Do it with your own numbers before every trip, because the answer changes every time the load changes.

Tongue weight table for caravan towing calculator

Taking caravan towing calculator as the case in point: The table shows the 10 to 15 percent tongue-weight range for common loaded trailer weights. The middle column is 12.5 percent, a useful target when you are loading. All figures are calculated from the trailer weight — weigh your own trailer, do not guess it.

Loaded trailer weight (kg) 10% tongue weight 12.5% tongue weight 15% tongue weight
1,200 120 150 180
1,500 150 188 225
1,800 180 225 270
2,000 200 250 300
2,500 250 312 375

The four checks, in order for caravan towing calculator

Check What to compare Passes when
Tow rating Trailer weight against the lowest of the three ratings Trailer is at or below the lowest rating
Tongue weight Tongue weight against 10–15% of trailer weight Percentage sits inside 10–15%
Payload Tongue weight + passengers + cargo vs payload Total is at or below payload
GCWR Vehicle + trailer loaded weights vs GCWR Combined weight is at or below GCWR

caravan towing calculator: Common mistakes

  • Taking caravan towing calculator as the case in point: Skipping the brake check on the trailer. A trailer's brakes need testing before every trip, not just at service time — a seized or disconnected trailer brake puts the whole stopping job on the tow vehicle.
  • On this page, caravan towing calculator is the case in point: Driving at solo speeds while towing. Speed limits for towing are lower in most places, and stopping distances and sway risk both grow sharply with speed, so the right speed while towing is well below the solo limit.
  • On this page, caravan towing calculator is the case in point: Trusting a figure quoted for a different year, engine or configuration. Tow ratings change with engine, axle ratio, cab and tow package, so only the numbers for your exact vehicle count.
  • Taking caravan towing calculator as the case in point: Forgetting that tongue weight counts against payload. The hitch load is carried by the tow vehicle, so it reduces the passengers and cargo you can carry by exactly that amount.

caravan towing calculator: Related calculations

For the next step, these pages apply the same method to a closely related question — or hand the arithmetic to the calculator. That is the point this page works through for caravan towing calculator.

caravan towing calculator: Putting your figure to work

Taking caravan towing calculator as the case in point: Use the method as a pre-trip routine. Before you hitch up, weigh the loaded trailer, confirm the three ratings from your own documents, calculate the tongue weight and check it against payload and GCWR. Note the four results and keep them with the trailer's documents. Any change in load — water, luggage, passengers, a different trailer — means a fresh check, because the numbers move with the load. Done every trip, the routine takes minutes and keeps the combination inside its limits where it matters: on the road.

Frequently asked questions

Can I exceed my towing capacity?

No. The tow rating is a maximum set by the manufacturer for the vehicle's engine, transmission, brakes and cooling, and exceeding it increases braking distances, overheats the transmission, reduces stability and can be illegal. It can also void warranty coverage and give an insurer a reason to refuse a claim. If the trailer is heavier than the lowest of the three ratings, you need a different vehicle, a different tow bar or a lighter load. That is the point this page works through for caravan towing calculator.

How do I work out my towing capacity?

Take the lowest of three ratings: your vehicle's tow rating, your tow-bar rating and the trailer's ATM. Then check the tongue weight is 10 to 15 percent of the trailer weight, and check the combination against GVWR, GCWR and payload. All four checks have to pass. The ratings come from your owner's manual, the door-jamb sticker, the tow-bar plate and the trailer plate — not from a figure quoted for a different vehicle.

How much trailer can I tow?

It depends on the lowest of your vehicle's tow rating, your tow-bar rating and the trailer's ATM, capped by GVWR, GCWR and payload. In this page's worked example the lowest rating is 1,800 kg. Substitute your own three ratings and run the same check — the answer is specific to your vehicle and your trailer, not a general figure.

Do I need a special licence to tow?

On this page, caravan towing calculator is the case in point: It depends on where you are and how heavy the combination is. Licence categories limit the combined weight you may tow, and the rules differ by country. Check your licence entitlement before towing, not after you are stopped.

What is tongue weight and why does it matter?

Tongue weight is the downward force the trailer puts on the hitch. It should be 10 to 15 percent of the trailer's loaded weight — for a 1,200 kg trailer that is 120 to 180 kg. Too little causes sway; too much overloads the tow vehicle's rear suspension and lightens the steering. Load the trailer to get the percentage right, then re-weigh.