Motorhome Minimum Payload: What Your Build Must Leave Free

30.09.2026 · 9 min read

Reading time: approx. 7 minutes

Everyone asks the same payload question: how much is left for me? Gross vehicle weight minus kerb weight, done.

There is a second question almost nobody asks, even though an EU regulation answers it: how much payload must stay free for the vehicle to count as a motorhome at all? That is not a guideline or a comfort tip. It is the reason manufacturers cap the optional equipment you can order — and depending on where you register your conversion, it is the figure it fails on, even though the scales stay under 3.5 t.

The formula

The minimum payload of a motorhome:

Minimum payload in kg ≥ 10 × (n + L)

  • n = the maximum number of passengers plus the driver, meaning every seat that may be occupied while driving
  • L = the overall length of the vehicle in metres

On top of that comes the mass of the occupants: 75 kg per seat, a flat figure, regardless of what anyone actually weighs. The driver is already included in the mass in running order and is not counted twice.

A vehicle 6.00 m long with 4 seats:

  • Minimum payload: 10 × (4 + 6) = 100 kg
  • Passengers: 3 × 75 = 225 kg
  • Together, 325 kg must stay free.

The formula sits in EU Implementing Regulation 2021/535, which replaced the earlier Regulation 1230/2012 on 6 July 2022. The easiest place to read it is at the manufacturers themselves — Dethleffs and Carthago both quote it verbatim in their weight information.

Why the rule exists at all

It protects the buyer from a motorhome that leaves the forecourt fully equipped and can then carry nothing.

Every factory extra — awning, carrier, solar panel, second battery — comes off the payload. Without a floor, a manufacturer could equip a vehicle so heavily that almost nothing is left for water, gas and luggage. That is precisely why manufacturers limit the maximum optional equipment you can order: Dethleffs names it as the reason. The minimum payload is a consumer-protection rule wearing the costume of a weight rule.

For the self-builder it flips around. You are manufacturer and buyer in one person — and the floor meant to protect you becomes the bar you have to clear yourself.

Three vehicles, three numbers

Pure arithmetic from the formula, no vehicle data:

Overall length Seats Minimum payload Passengers Must stay free
5.40 m 2 74 kg 75 kg 149 kg
6.00 m 4 100 kg 225 kg 325 kg
7.00 m 3 100 kg 150 kg 250 kg

Two things stand out. First: seats cost more than length. One more metre of vehicle costs 10 kg; one more seat costs 85 kg — 10 kg in the formula plus 75 kg of occupant mass. If your build is tight, think hard about that fourth seat.

Second: the 7-metre vehicle with three seats has to leave less free than the 6-metre one with four. In this calculation, length is the cheaper item.

And now the part nobody else writes

The formula is EU law — but it is type-approval law. It addresses the manufacturer getting a model approved. Whether it is also checked when you convert an already registered panel van and have it reclassified is decided by the national procedure. And that looks completely different from country to country:

Country Who reclassifies Minimum payload checked?
Germany Approved inspector, individual approval Yes — it is in the guidance sheet he works from
France DREAL, réception à titre isolé Yes — it is in the official application form
Switzerland Cantonal road traffic office No
United Kingdom DVLA, V5C body type change No
Netherlands RDW No — interior dimensions count there
Italy Motorizzazione Civile No
Poland OSKP test station, then registration office No
Spain ITV after a reforma de importancia open
Portugal IMT open
Austria Provincial test centre, §33 KFG open

United Kingdom. Converting a van into a motor caravan is not an approval procedure at all. It is a change to the “body type” field on the V5C, handled by the DVLA: you send in the motor caravan conversion checklist, interior photos with the bed and table deployed, exterior photos and a photo of the VIN plate. DVLA’s own guidance lists the features required — seats and a table, sleeping accommodation, cooking facilities and storage, all rigidly fixed, plus external features such as two side windows, a separate habitation door, a high-top roof or an awning bar. It says nothing about payload, load capacity or mass.

So the 10 × (n + L) formula does exist in UK law — Regulation 1230/2012 was carried over as assimilated law and sits on legislation.gov.uk with the figure intact. But it lives in the type-approval world, not in the DVLA conversion route. For a van already registered in the UK, Individual Vehicle Approval is not required either; DVLA describes it as a voluntary safety check of the modifications.

That makes the UK the most permissive of the ten on paper — and it changes nothing about physics. Overloading still costs the same on the road, and the vehicle still has to carry what you put in it.

Germany is the clearest “yes”. No German statute sets a minimum payload; the legal definition — Annex XXIX No. 5.1 StVZO — only requires a table and seats, sleeping accommodation, a cooking facility and storage, all rigidly fixed in the living area. Not a word about weight. It is checked anyway, because the inspector works from guidance sheet MB FZMO 0740 of the TÜV association, current version 21 May 2024, and that sheet contains the 10 × (n + L) formula, quotes Regulation 1230/2012 repeatedly, and states that 75 kg is to be counted for every seat that may be occupied while driving. Worth knowing: the sheet is an association recommendation, not a legal norm. It binds the inspector in practice, not in law.

France goes the other way and writes the figure straight into the procedure. The official application sheet for the réception à titre isolé of a conversion to an autocaravane requires a charge utile minimale of at least 10 × N + 10 × L and defines how to establish it. A conversion that substantially changes the vehicle has to be re-approved there in any case — nothing about it is voluntary.

After the build, it gets weighed again

This is where the rule turns awkward for self-builders, for a reason that slips past on first reading: once approved, the fixed build counts towards the kerb weight, not the payload.

While your panel van is a panel van, furniture is cargo. The moment it is registered as a motorhome, furniture is vehicle. From then on the sum reads:

gross vehicle weight − new kerb weight ≥ passengers + minimum payload

A self-build weighs 400 to 500 kg dry. That range is not an estimate; it is documented part by part with manufacturer figures in How much does a van conversion weigh?. On a 3.5-tonner with roughly 1,200 kg of payload, that leaves about 700 to 800 kg — the 325 kg from the example above come off that comfortably.

It gets tight in the combination that is common in self-builds: small vehicle, heavy build, four registered seats. On a 3-tonner at 6 m with four seats, 325 kg have to be reserved before the first board goes in — and how much reserve a vehicle brings in the first place is decided at purchase: up to 155 kg separate the common 3.5-tonners, as set out in Which base van for a camper conversion?.

The minimum payload is also only one limit among several. The total can be fine while the front axle is overloaded — that calculation is in Campervan axle load. What overloading costs when it goes wrong is in Overloading a motorhome: fines and limits.

How to check this for your vehicle

  1. Count the seats that may be occupied while driving — not the berths. This is the most expensive item in the sum.
  2. Take the overall length, not the load area. At 10 kg per metre, half a metre of guesswork costs 5 kg.
  3. Do the maths: 10 × (seats + length in metres), plus 75 kg per seat other than the driver.
  4. Hold it against your remaining budget. Gross vehicle weight minus kerb weight after the build. How to read both figures off the registration document, and how to weigh axle by axle on a public weighbridge, is in the two articles linked above — it is not repeated here.
  5. Do it before you build. Afterwards the only levers left are removing seats or uprating the vehicle.

And if you do not have the vehicle yet: the vehicle database gives you dimensions and weights for the common panel vans before you commit.

VanLogic works out both figures while you plan. “Legally required remaining payload” shows what has to stay free, derived from seat count and vehicle length. Below it, “Actually available remaining payload” shows what is left after your current build. As long as the second number stays above the first, you have room. You see it while you are moving the bed, not at the inspection.

Run the payload numbers in your browser — free, no sign-up

Conclusion

Minimum payload is the only weight limit in a conversion that pushes from below instead of above. Every other figure tells you how much more you may load. This one tells you how much you have to leave alone.

The formula is the same across the EU. Whether it is checked on your conversion is decided where you register it: in France it is in the application form, in Germany in the inspector’s guidance sheet, in Switzerland and the UK nowhere at all. If you build in one country and register in another, find that out beforehand — not on inspection day.

→ Calculate the payload for your build — vanlogic.app

Sources

All figures retrieved on 30 September 2026.

Where the table says “open”, it means this: no minimum payload could be found in the publicly available documents of those countries, and no explicit statement that there is none either. Spain is missing detail sheet CR 8.70 of the Manual de Reformas, Portugal Deliberação 291/2019, Austria an official statement on weight. If you are converting there, ask the test centre before you build.