Online Tool Store
Towing Capacity Checker
Check a loaded trailer against your tow vehicle payload rating and the 80% safe towing rule, computing tongue weight and total payload used from your gear and passenger load.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Towing Capacity Status
Vehicle Payload Utilization
Trailer Hitch Tongue Weight
How it works
- Enter your tow vehicle manufacturer towing capacity and door-jamb payload rating (in lbs or kg).
- Enter the total gross loaded weight of your trailer, boat, or camper.
- Input the weight of all vehicle occupants and interior luggage cargo.
- The calculator computes trailer tongue weight (10%–15%), evaluates overall towing margins against the 80% safety rule, and validates payload limits.
The formula
Tongue Weight = Loaded Trailer Weight × Tongue Percentage (10% to 15%)
Total Payload Used = Passenger & Cargo Weight + Tongue Weight
Safe Towing Margin = Max Tow Capacity × 0.80 − Trailer Weight
FAQ
Why does payload capacity limit towing more than maximum tow rating?
Every conventional bumper-pull trailer pushes down on the vehicle's hitch ball with 10% to 15% of its total weight (the tongue weight). This tongue weight counts directly against your tow vehicle's door-jamb payload capacity, alongside the weight of passengers, luggage, and truck accessories.
What is the 80% towing rule?
The 80% rule is an industry safety best practice advising that your loaded trailer should not exceed 80% of your vehicle's maximum advertised towing capacity. This 20% safety margin ensures reliable engine cooling, transmission longevity, and stable braking down steep mountain grades.
What happens if tongue weight is too low (under 10%)?
If trailer tongue weight drops below 10% (due to heavy cargo loaded at the rear of the trailer), the trailer becomes aerodynamically unstable and prone to catastrophic high-speed trailer sway (fishtailing).
Where can I find my vehicle exact payload and towing numbers?
Check the Tire and Loading Information sticker located on the driver's side door jamb (B-pillar) for your vehicle's specific payload rating as manufactured.
How we compare
| Feature | Online Tool Store | Dealership marketing brochures | Generic towing charts |
|---|---|---|---|
| Combined Towing & Door Payload validation | ✓ | ✗ (Hides payload limits) | ✗ |
| 80% RV safety margin evaluation | ✓ | ✗ | ✗ |
| Dual units (lbs & kg) support | ✓ | Partial | ✓ |