Two things this does that other payload calculators do not
The basic sum is not hard and plenty of sites do it: gross vehicle weight minus kerb weight equals payload. The problem is that the answer it gives is usually wrong in the same two ways.
1. The brochure figure is for a van you do not own
Payload in a brochure is quoted from a bare van. Yours has racking down both sides, a ply lining, a towbar, a ladder rack and a roller on the roof. That is comfortably two hundred kilos, and none of it is in the brochure number.
It gets worse when you look at the definitions.GOV.UK defines mass in running order as including the driver, oil and a full tank of fuel, while unladen weight, a separate legal term, expressly excludes fuel, water and loose tools and equipment. Two official figures for the same van, differing by the weight of a person and a tank of diesel, and which one a manufacturer quoted is not always obvious.
So this tool asks what is bolted to it and how many people are in the cab, and then shows you the gap: what the brochure claimed, what the fit-out already took, and what you actually have left.
2. You can be overloaded while under your gross weight
This is the one that catches experienced drivers, and it is the reason the tool exists.
Every van has a plated limit for each axle as well as for the vehicle. Load everything at the back doors and the rear axle can be over its limit while the total sits comfortably inside the gross figure. In the UK that is a separate matter carrying a fine of up to £300 or a court summons in its own right.
Every free payload calculator we can find ignores axles completely.
Why a load can weigh more than it weighs
Because of leverage, and this is the part that surprises people.
A load sitting behind the rear axle pivots about it: pressing the back down while lifting weight off the front. So 400 kg on a tail lift can add well over 400 kg to the rear axle, and the front axle reading actually falls. Same reason a wheelbarrow feels light at the handles and heavy at the wheel.
Which is why this tool asks where each item sits rather than only what it weighs:
- Against the bulkhead: most of it on the front axle. Best place for anything heavy.
- Middle of the load area: roughly two thirds on the rear.
- At the back doors: almost all of it on the rear.
- Behind the rear axle or on a tail lift: more than its own weight on the rear.
Those are typical factors for a panel van, not measurements of your van. A weighbridge is the authority. What this gives you is whether it is worth finding one, and which end to move weight away from.
The UK numbers, and where they come from
From DVSA's published fixed penalty guidance:
- Under 10 per cent over: £100
- 10 up to 15 per cent: £200
- 15 per cent and above: £300
None are endorsable. Examiners allow 5 per cent before issuing a penalty or a prohibition, unless the weight is exceeded by a tonne or more, at which point the allowance stops applying regardless of percentage. At 30 per cent over, or 5 tonnes excess, a fixed penalty is inappropriate and a court summons is issued instead.
And in every case the vehicle gets an immediate prohibition and may be immobilised, which for most firms is the expensive part. The fine is not what hurts; the van sitting in a lay-by with the job not done is.
Treat that 5 per cent as a weighing tolerance rather than a margin to load into. It is there because scales have error, not because the limit is negotiable.
Four markets, one sum
Kerb weight plus everything in or on the vehicle against the plated maximum. That is physics and it is identical everywhere, so this is one tool rather than four pages.
What differs is the vocabulary and the consequence. The plate says gross vehicle weight in the UK, gross vehicle mass in Australia, and gross vehicle weight rating in the US and Canada, and the US works in pounds.
We state licence thresholds and penalties only for the UK, because GOV.UK is the only regulator we read for this. For the other three the tool does the arithmetic, converts the units, uses the right name, and says plainly that the thresholds are set locally and the plate is the authority. An invented figure for Queensland would be worse than no figure at all.
Nothing is saved, and there is no PDF
Deliberately. This is a checker rather than a document: you want the answer in a yard, on a phone, before the van moves. Nothing is uploaded, nothing is stored, and closing the tab clears it.
If you are moving steel about, the lift plan uses the same weights, and a site diary is where the delivery ends up recorded.
Common questions
Why is my real payload so much less than the brochure said?
Because brochure payload is quoted from a bare van. Racking, ply lining, a towbar, a roof rack, a ladder rack and a second person are all payload, and none of them are in that figure. Two hundred kilos of fit-out is normal, and it came off the day it was fitted rather than the day you loaded the van.
Can I be overloaded while under my gross vehicle weight?
Yes, and it is the commonest way a van fails a roadside check that its driver thought was fine. Each axle has its own plated limit. Load everything at the back doors or on a tail lift and the rear axle can be over while the total is comfortably under. In the UK, exceeding a maximum permitted axle weight carries a fine of up to £300 or a court summons in its own right.
How can a load put more than its own weight on the rear axle?
Leverage. A load sitting behind the rear axle pivots about it, pressing the back down and lifting weight off the front. So 400 kg on a tail lift can add well over 400 kg to the rear axle while the front axle reading actually falls. It is the same reason a wheelbarrow feels light at the handles.
What are the UK penalties for overloading?
Excess weight fixed penalties are £100 for under 10 per cent over, £200 from 10 up to 15 per cent, and £300 at 15 per cent and above, none of them endorsable. DVSA examiners allow 5 per cent before issuing a penalty or prohibition, unless the weight is exceeded by a tonne or more. At 30 per cent over, or 5 tonnes excess, a fixed penalty is inappropriate and a court summons is issued instead. An overloaded vehicle also gets an immediate prohibition and may be immobilised.
Does it work outside the UK?
The arithmetic does, because it is physics: kerb weight plus everything in or on the vehicle against the plated maximum. The tool switches units and uses the right name for the plate, gross vehicle mass in Australia, gross vehicle weight rating in the US and Canada. It states no licence thresholds or penalties for those markets, because we have not read those regulators and will not guess. The plate is the authority.
How accurate are the axle figures?
They are estimates from where you said the weight sits, using typical position factors for a panel van. A weighbridge is the authority. What this does is tell you whether it is worth finding one, and which end to move weight away from, which is more than a calculator that ignores axles altogether can do.