How is this calculated?
Available payload = GVWR - curb weight - passengers - cargo - tongue weight Max trailer by GCWR = GCWR - loaded tow vehicle weight Recommended tongue weight = 10% to 15% of trailer weight Safe tow = min(manufacturer tow rating, GCWR - loaded vehicle weight) Use one weight unit consistently: lb, kg or metric tonnes.
Example: a truck with 7,200 lb GVWR, 14,500 lb GCWR, 5,200 lb curb weight, 700 lb passengers/cargo and an 800 lb tongue weight has 500 lb payload remaining.
How do I use this calculator?
- Choose the unit or currency setting that matches your vehicle data.
- Enter the required vehicle, route, fuel, weight or loan values in the calculator form.
- Review inline warnings and correct any missing or negative inputs.
- Read the live result card for the primary answer and supporting totals.
- Use the worked example if you want to check the formula with sample values.
- Copy, share or print the results for comparison or record keeping.
What do the terms mean?
- GVWR
- Gross Vehicle Weight Rating, the maximum loaded vehicle weight.
- GCWR
- Gross Combination Weight Rating, maximum loaded vehicle plus trailer weight.
- Curb weight
- Vehicle weight with standard equipment and fluids, before people and cargo.
- Tongue weight
- Trailer weight carried on the hitch.
- Payload
- Weight available for people, cargo, hitch equipment and tongue weight.
What are real-world examples?
| Scenario | Inputs | Result | Notes |
|---|---|---|---|
| Half-ton truck | 7,200 GVWR, 14,500 GCWR | Safe around 8,600 lb | Before manufacturer cap |
| Midsize SUV | 6,000 GVWR, 10,000 GCWR | Limited by payload | Tongue weight matters |
| HD pickup | 11,500 GVWR, 30,000 GCWR | High trailer margin | Check hitch class |
| Travel trailer | 7,000 lb trailer | 700-1,050 lb tongue | 10-15% target |
What tips improve accuracy?
- Use scale weights when possible, not brochure curb weights.
- Payload is often the first limit for travel trailers.
- Weight-distribution hitches do not increase GVWR or GCWR.
- Keep tongue weight near 10% to 15% for bumper-pull trailers.
- Check tire, axle, hitch and brake controller ratings too.
- SAE J2807 gives a standardized tow-rating test method, but real payload still matters.
Did you know? EPA estimates commonly use 8.89 kg CO2 per gallon of gasoline and 10.18 kg CO2 per gallon of diesel for tailpipe carbon dioxide calculations.
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Frequently asked questions
What tongue weight should I use?
For most bumper-pull trailers, use 10% to 15% of loaded trailer weight unless the trailer manufacturer specifies a different range.
Does a weight-distribution hitch increase tow rating?
No. It can improve load distribution when used correctly, but it does not increase manufacturer GVWR, GCWR, axle ratings or tire ratings.
Is this calculator free to use?
Yes. The calculator runs in your browser, does not require an account and can be printed or copied for your records.
Can I use this for official tax, loan or compliance filing?
Use it as an estimate. For official filing, financing or enforcement decisions, verify the final numbers with your lender, tax authority, manufacturer rating label or compliance professional.
Why are my real-world results different?
Real vehicles vary with load, speed, terrain, temperature, tire condition, maintenance, driver behavior and measurement quality.
Does the calculator save my units?
Yes. Unit and currency selections that are marked as preferences are stored in localStorage on your device so the next visit starts with your preferred setting.
Can I share the result?
Yes. Use the Share button if your browser supports native sharing, or copy the permalink and result summary.
Does it work on mobile?
Yes. The layout stacks on small screens, keeps labels visible and recalculates as you type.
How accurate are the formulas?
The formulas are standard industry math for estimates. Accuracy depends on the input values and whether the assumptions match your vehicle and jurisdiction.
When was this page updated?
This page was last updated on 2026-05-01 for 2026 planning assumptions and source links.