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Tool Belt Calc

Automotive

Towing Capacity Calculator

Maximum trailer weight from GCWR and what you are carrying.

Your measurementsEvery assumption editable01

Gross combined weight rating, from the door placard or handbook.

10–15% of trailer weight for a conventional hitch.

Maximum trailerCalculated live02

Result

7009lb trailer

7009 lb maximum, with 841 lb on the tongue

GCWR
14000 lb
Curb weight
5600 lb
Passengers and cargo
550 lb
Loaded vehicle weight
6150 lb
Available for the trailer
7850 lb
Maximum trailer weightafter allowing 12% tongue weight
7009 lb
Tongue weight at that figure
841 lb

This is an estimate from one rating. Real towing capacity is limited by whichever of several ratings you hit first — GCWR, GVWR, rear axle rating, hitch rating and tyre load rating — and the lowest of them governs. Your door placard and handbook are the authority, not this page.

Tongue weight is not free. It sits on the tow vehicle, so it consumes payload as well as counting toward the combined weight, which is why the arithmetic above divides rather than simply subtracting.

Too little tongue weight is more dangerous than too much. Below roughly ten per cent a trailer becomes prone to sway, and sway at speed is very difficult to recover from.

Enter your GCWR and everything already in the vehicle. Tongue weight consumes capacity twice — it counts toward the combined weight and it sits on the vehicle — which is why the arithmetic divides rather than subtracting. Your door placard is the authority, not this page.

Why use this tool?What it does differently03

Why use this tool?

Tongue weight handled properly

It rides on the tow vehicle as well as counting toward the combined total, so it consumes capacity twice.

Names the real limits

GCWR, GVWR, axle, hitch and tyre ratings all apply, and the lowest governs. This uses one of them.

Loaded weight shown

Passengers and cargo eat into towing capacity before the trailer is attached.

Sway warning

Too little tongue weight is more dangerous than too much, and the result says so.

How this worksThe method04

How this towing capacity calculator works

Loaded vehicle weight is curb weight plus passengers plus cargo. Subtracting that from GCWR gives what remains for the trailer and everything on it.

Tongue weight is not free. It rests on the tow vehicle, so it consumes payload as well as counting toward the combined weight — which is why the available figure is divided by one plus the tongue percentage rather than simply reduced by it.

This uses one rating. Real capacity is governed by whichever of GCWR, GVWR, rear axle rating, hitch rating and tyre load rating you reach first, and the lowest of them wins. Your door placard and handbook are the authority.

How to use itStep by step05

How to use it

  1. Step 1: Find your GCWR

    Gross combined weight rating, from the handbook or the door placard.

  2. Step 2: Enter curb weight

    The vehicle empty, from the same source.

  3. Step 3: Add passengers and cargo

    Everything that will be in the vehicle while towing.

  4. Step 4: Check the other ratings

    GVWR, axle, hitch and tyre ratings all apply. The lowest governs, not this figure.

Example usageWorked figures06

Example usage

A half-ton truck
14,000 lb GCWR, 5,600 lb curb, 350 lb passengers, 200 lb cargo — 7,850 lb available, so about 7,009 lb of trailer with 841 lb on the tongue.
Loaded for a holiday
The same truck with 700 lb of passengers and 600 lb of cargo drops to about 6,339 lb of trailer. An extra 550 lb inside the vehicle costs about 670 lb of towing capacity.
A heavier tongue percentage
The first case at 15% rather than 12% tongue weight reduces the trailer to 6,826 lb — but gives far better stability.
Frequently asked questionsCommon questions07

Frequently asked questions

How much can my vehicle tow?

Subtract everything already loaded from your GCWR, then allow for tongue weight. But the governing limit is the lowest of GCWR, GVWR, axle, hitch and tyre ratings — check all of them.

What is tongue weight and why does it matter?

The downward force the trailer places on the hitch, normally 10 to 15 per cent of trailer weight. It consumes vehicle payload as well as counting toward combined weight.

What happens if tongue weight is too low?

The trailer becomes prone to sway, and sway at speed is very difficult to recover from. Too little is considerably more dangerous than too much.

Do passengers reduce towing capacity?

Yes, directly. Every pound in the vehicle is a pound unavailable for the trailer, which is why a fully loaded family car tows substantially less than the brochure figure.

Can I trust this number?

Treat it as an estimate from one rating. Your door placard and handbook are the authority, and exceeding real capacity is a safety matter rather than a cost one.

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