Weight & Payload Planner
Place your components, see where the weight sits, and plan your remaining payload.
Read the Weight & Payload Planner guide
Anyone can plan here. Sign in to save plans and bring in your project’s builder-adjusted weights.
Scenarios are saved with the plan. Project weights refresh when the plan opens or saves.
Planning data review
This checks selected planning data, not roadworthiness or driving safety. Understand the review.
Select an item, then place or drag it. Numeric positions below work with a keyboard or on a phone. Overlaps are allowed between floors, walls and roof items.
Darker cells indicate more weight per area in the visible layers. The red marker is the center of all positioned items in the selected loading. Exterior weights are included; front/rear overhang weights contribute to the nearest end region.
Density and the positioned-item center assume weight is spread evenly over each footprint. They describe mapped components, not the complete trailer’s center of gravity or axle/hitch loads.
Selected item
Select an item from the list or map.
Move several items
Check items here to move or rotate them together. This selection is separate from whether an item counts in the loading.
Read the totals with your build in mind
Items without a position still count in known weight. Unknown weights are listed rather than treated as zero. Compare your completed load with actual scale readings and the vehicle or trailer’s ratings.
For water, add a manual item and choose Water contents to vary its fill level separately from the dry tank. Add supplies and other loads as manual items. Use the baseline checkbox to account for anything already included in a weighing.
Scale checks use entered measurements rather than equal shares of the axle group. Changing a layout or load marks prior readings for reweighing. Torsion axle loading depends on trailer attitude and suspension design.
References: NHTSA certification-label ratings · Dexter axle and suspension guidance · Water-density convention (1 kg/L). Water contents use 1 kg per litre; displayed gallon capacity is US gallons.
Planning limitations & verification
This planner provides estimates and layout illustrations for planning and documentation. It does not certify a vehicle, trailer, conversion, or towing combination as safe or roadworthy. Staying below entered ratings or seeing no warnings does not establish safe handling or prevent sway, rollover, or loss of control.
The planner does not assess dynamic cornering or braking forces, complete vehicle center of gravity, individual axle or hitch loads from component placement, structural strength, mounting or cargo restraint, tire/wheel capacity, or towing-vehicle compatibility. Its map and 3D view are simplified representations.
Before driving or towing, verify actual loaded scale weights, each applicable rating and clearance, secure mounting, and the current instructions for your vehicle, trailer, suspension, tires, wheels and hitch. Obtain a qualified assessment where needed. You remain responsible for the build, loading and operation.
Verify references are current and applicable. Linked regulations, interpretations and manufacturer manuals can change or address different equipment. Check current official sources and your equipment manufacturer; NPPSC links are guidance, not approval of your installation.
Saved plans are private to your account. Project imports are available to the builder and active co-builders and assistants. Each teammate saves their own private plans.