Project GVM Free 4WD GVM calculator for payload, axle loads and towing planning

Free GVM Calculator

Use the free GVM calculator to see how vehicle modifications, payload and towing load affect total weight and axle loading in real time.

Built by an enthusiast, for the 4WD community

Project GVM was built to solve the GVM headaches on a real 200 Series touring build. Instead of rough spreadsheet guesses, this tool helps visualise how accessories, payload and tow ball weight affect both your total vehicle weight and your front and rear axle loads.

Latest Blog Articles

4WD towing safely with proper weight distribution

Towing Safely: Tips & Tricks

Learn safe towing techniques, legal limits and common towing mistakes.

Read the towing guide
Understanding GVM and GCM for Australian 4WDs

Understanding GVM & GCM

A practical guide to vehicle weight ratings, compliance and what the terms actually mean.

Read the GVM & GCM guide
4WD touring accessories and payload considerations

Top 3 Accessories for Touring

What adds real value to a touring setup without blowing out your payload.

Read the accessory guide

Plan Your 4WD Setup Properly

Check GVM

See how close your setup is to your vehicle’s total legal loaded weight limit.

Axle Loads

Understand front and rear axle loading, not just the final total weight figure.

Towing Impact

Estimate how tow ball weight affects your rear axle and overall payload.

Accessory Effects

Model common modifications like bullbars, roof loads, drawers, canopies and rear bars.

Launch Free Calculator

Why This Calculator Is Different

📐 Vehicle Geometry

Project GVM uses representative vehicle geometry and mounting positions to estimate how weight shifts across the axles.

🔩 Real Accessory Data

Accessories are selected using real brand and model data where available, reducing guesswork.

⚖️ Axle-Focused Results

Many 4WDs run out of rear axle capacity before total GVM. This tool helps highlight that early.

🧠 Built for Real Setups

Designed for touring builds, towing setups and modified 4WDs rather than generic payload examples.

Built From Real 4WD Experience

Project GVM was created to make 4WD weight planning more practical. It is built for owners trying to understand how accessories, passengers, fuel, cargo and tow ball download affect their vehicle before heading to a weighbridge.

It is a planning tool, not a certification tool. For legal, registration and compliance requirements, always verify final figures using a certified weighbridge or qualified engineer.

Learn how the calculator works Read the weighbridge guide

Supported 4WD Platforms

Toyota

  • LandCruiser 200 Series
  • LandCruiser 300 Series
  • LandCruiser 79 Series
  • Prado

Ford & Nissan

  • Ford Ranger
  • Ford Everest
  • Nissan Patrol Y62
  • Nissan Patrol GU

Others

  • Isuzu D-MAX
  • Isuzu MU-X
  • Mazda BT-50
  • Volkswagen Amarok

Looking for more? The calculator includes additional supported vehicles and is updated over time.

See the full calculator and vehicle list

Common 4WD Weight Questions

Does tow ball weight count towards GVM?

Yes. Tow ball download counts as payload on the vehicle and usually adds significant load to the rear axle.

Why is rear axle load important?

Many 4WDs exceed rear axle capacity before reaching their total GVM because heavy loads are often carried near or behind the rear axle.

Does suspension increase legal GVM?

No. Suspension may improve how a vehicle carries weight, but legal GVM only changes with an approved certified GVM upgrade.

Need more detail? Visit the full FAQ page

Helpful Guides

Free GVM Calculator Using a Weighbridge How the Calculator Works Understanding GVM & GCM Suspension Airbags Touring Accessories