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Measured payload and axle weight calculator

Compare weighbridge readings with your vehicle’s gross, front and rear axle limits. Calculate headroom in kg or lb, share inputs and print results.

Turn a weighbridge ticket into three clear checks. Enter your own plated limits and measured readings; gross headroom and axle headroom are shown separately.

Your measured weights

Use figures for the same vehicle and load. This form supports a vehicle with front and rear axles; it does not assess a trailer, axle groups or a vehicle with three or more axles.

Gross vehicle weight — required

Use the applicable gross vehicle limit, not gross train weight. Ask the manufacturer or relevant authority if the plate is unclear.

Individual axle checks — optional pairs

Enter both a limit and a reading for each axle you want to check. A missing axle stays “not assessed”. Never add the axle limits together to create a gross limit.

Enter your weights or load the worked example.

Sharing includes all values in the link. Calculations run in your browser; no account is needed.

How the payload calculation works

Gross headroom = applicable gross limit − measured gross weight. The front and rear calculations each subtract that axle’s measured weight from its own limit. A negative answer is an exceedance, zero is exactly at the entered limit, and a positive answer is remaining arithmetic headroom for that measurement.

This measured approach is useful for vans and two-axle motorhomes because it starts with what is actually on the weighbridge. Brochure payload figures cannot account for everything in your particular vehicle. Record who was aboard and the fuel, water and equipment present when weighed. If they change, the result describes the earlier condition.

Worked example: gross headroom with an overloaded axle

These illustrative figures do not describe a particular vehicle. A gross limit of 3,500 kg minus a measured 3,350 kg leaves 150 kg of gross headroom. A front limit of 1,850 kg minus 1,320 kg leaves 530 kg. A rear limit of 2,000 kg minus 2,030 kg shows a 30 kg rear axle exceedance. The gross figure does not cancel it out. The example button enters these exact figures.

What is maximum authorised mass?

GOV.UK describes maximum authorised mass (MAM), also called gross vehicle weight, as the maximum permitted loaded weight. The applicable figure is normally on the vehicle plate or sticker. It is a limit, while the weighbridge ticket is a measurement. Read the official weight definitions.

Using the result responsibly

  • Copy plate and ticket numbers carefully. Confirm the unit and which line is gross vehicle weight.
  • If only gross weight was measured, leave the axle pairs blank. No axle result can be inferred.
  • Adding load changes individual axle loads. A positive gross result does not identify where, or whether, more can be carried.
  • Use the load planner to explore additions, then obtain fresh loaded readings.
  • This tool does not check tyre ratings, load securing, towing limits, licence entitlement, vehicle condition or measurement uncertainty. It applies no enforcement tolerance.

Units and rounding

One pound equals 0.45359237 kg. Changing unit converts every entered weight. Calculations retain full precision; results display to 0.1 kg or lb. A very small non-zero difference is labelled “less than 0.1” rather than hidden as zero. Exactly at the limit leaves no headroom.

Next steps

Find a public weighbridge, confirm that individual axle weighing is offered, and check access before setting off. Our practical weight guides help you prepare for a visit and read the resulting ticket.

Sources and method review

Official sources checked 19 October 2026: GOV.UK: vehicle weights explained; DVSA: driving a van, weight limits and loading. DVSA’s van guidance warns about individual axle overloading as well as vehicle overloading. The tool performs subtraction only; it does not certify legal compliance.

Keep planning

Find a public weighbridge · Plan added loading