How it works
A trailer’s cargo capacity is the difference between its gross vehicle weight rating and what it weighs empty. The calculator also checks the running gear: the axles and tires carry the whole load except the share that rests on the hitch.
Cargo capacity = GVWR − empty weight
Load on axles = (empty weight + cargo) × (1 − tongue %)
Effective limit = lowest of GVWR, axle ratings ÷ (1 − tongue %), tire ratings ÷ (1 − tongue %)
Worked example
A 7×16 tandem trailer: 7,000 lb GVWR, 2,100 lb empty, two 3,500 lb axles, four tires rated 2,150 lb each, 4,200 lb of pavers.
- Cargo capacity: 7,000 − 2,100 = 4,900 lb
- Loaded trailer: 6,300 lb (90% of GVWR: at the limit); axles carry 5,670 lb of 7,000 lb.
- Tires: 4 × 2,150 = 8,600 lb, plenty. Capacity left: 700 lb.
Typical trailer capacities
Example ratings only. Your trailer’s VIN plate and scale weight are what count.
| Trailer | Typical GVWR | Typical empty | Cargo capacity |
|---|---|---|---|
| 5×8 single-axle utility | 2,990 lb | 650 lb | 2,340 lb |
| 6×12 single-axle utility | 2,990 lb | 900 lb | 2,090 lb |
| 7×16 tandem landscape | 7,000 lb | 2,100 lb | 4,900 lb |
| 7×14 tandem dump | 14,000 lb | 4,300 lb | 9,700 lb |
| 18 ft car hauler | 7,000 lb | 2,000 lb | 5,000 lb |
| 7×16 enclosed cargo | 7,000 lb | 2,600 lb | 4,400 lb |
Heavy loads fill a trailer fast
Dense materials reach the limit long before the bed looks full. A single cubic yard of gravel weighs around 2,800 lb, more than the capacity of most single-axle utility trailers. Use the trailer load weight calculatorto convert a pile of gravel, sand or soil into pounds before you load it.
Place the load so about 10–15% rests on the hitch (see the load balance calculator), secure it with enough straps (tie-down calculator), and check that the tow vehicle can handle the loaded trailer.
Common mistakes
- Treating axle ratings as GVWR. Two 3,500 lb axles do not make a 7,000 lb cargo capacity.
- Guessing the empty weight. Ramps, toolboxes and spare tires add up; weigh it.
- Ignoring the tires. Tires are often the weakest link, especially after an axle upgrade.
- Forgetting the tow vehicle. A trailer within its own GVWR can still exceed your tow rating.