Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Tongue weight %
10.0%
Assessment
In safe range
Ideal tongue weight (lb)
650
Capacity margin (lb)
2,300
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter loaded trailer weight (lb).
- 2Enter measured tongue weight (lb).
- 3Enter vehicle tow capacity (lb).
- 4Read your tongue weight % on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Tongue weight should be 10–15% of loaded trailer weight. Too little causes sway; too much overloads the rear axle.
Worked example
Using the values the calculator loads with:
Inputs
- Loaded trailer weight: 5200 lb
- Measured tongue weight: 520 lb
- Vehicle tow capacity: 7500 lb
Results
- Tongue weight %: 10.0%
- Assessment: In safe range
- Ideal tongue weight (lb): 650
- Capacity margin (lb): 2,300
What each field means
Inputs
- Loaded trailer weight (lb)
- The loaded trailer weight used in the calculation, measured in lb. Starts at 5200 lb so you have a working example on load.
- Measured tongue weight (lb)
- The measured tongue weight used in the calculation, measured in lb. Starts at 520 lb so you have a working example on load.
- Vehicle tow capacity (lb)
- The vehicle tow capacity used in the calculation, measured in lb. Starts at 7500 lb so you have a working example on load.
Results
- Tongue weight %
- Returned as a percentage and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Assessment
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Ideal tongue weight (lb)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Capacity margin (lb)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the trailer tongue weight calculator work?
Tongue weight should be 10–15% of loaded trailer weight. Too little causes sway; too much overloads the rear axle.
What do I need to enter?
3 values: loaded trailer weight, measured tongue weight, and vehicle tow capacity. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the tongue weight % result mean?
It is returned as a percentage and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Trailer Tongue Weight Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/trailer-weight
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/trailer-weight" target="_blank" rel="noopener">Trailer Tongue Weight Calculator — RevenueLab</a> (2026).</p>
Source: [Trailer Tongue Weight Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/trailer-weight) (2026).