AutoMath
The car itself

Towing Capacity & Payload Calculator

Checks a trailer plus cargo and passengers against your tow rating and payload — tongue weight included — so you find out before the trip, not at the scale.

Your numbersSaved on this device only
Vehicle ratings (from the door jamb / manual)
Your load
✅ Setup status

Within

both tow rating and payload

✅ Tow rating and payload both OK
You're under the tow rating by 3,000 lb and have 530 lb of payload to spare. Tongue weight (720 lb) is already counted.
Available payload
2,000 lbGVWR − curb weight
Payload used
1,470 lbtongue + people + cargo
Payload left
530 lb
Tow margin
3,000 lb

What this computes

"Can my truck tow it?" is the wrong question — it's two questions. This checks both: is the trailer within the tow rating, and does the load (tongue weight + people + cargo) stay within payload? It flags whichever limit you'd breach, because the dangerous one is usually the one nobody checks.

The math

available payload = GVWR − curb weight
tongue weight     = trailer weight × tongue %
payload used      = passengers + cargo + tongue weight
within limits     = trailer ≤ tow rating
                    AND payload used ≤ available payload

The tongue-weight term is the one casual estimates drop — it's why "I'm under the tow rating" is not the same as "I'm legal and safe."

Most overloaded trucks are comfortably under their tow rating. They blew payload — through the hitch — and never knew.

How to use this

  1. Use your exact vehicle's numbers. Door-jamb sticker for GVWR, manufacturer towing guide for tow rating and curb weight by configuration.
  2. Weigh the trailer loaded, not empty — gear, water, and fuel add up fast.
  3. Set a realistic tongue percentage, 10-15% for conventional trailers; verify with a tongue scale.
  4. Add everyone and everything riding in the vehicle — payload is shared between people, cargo, and the hitch.

The tongue-weight trap

  • It's invisible on the tow number. Tow rating says nothing about what the hitch does to your rear axle and payload.
  • It scales with the trailer. A bigger trailer means more tongue weight eating payload exactly when you have least to spare.
  • It's a safety knob, not just a number. Too low causes sway; too high overloads — it has to be both correct and within payload.

What this calculator doesn't model

  • GCWR — the combined vehicle + trailer ceiling, which can bind first.
  • Rear axle (RGAWR) and hitch/ball class ratings, which have their own limits.
  • Weight-distribution hitches and brakes, which change safe behavior but not the weight totals.
  • Altitude, grade, and heat derating of real-world towing capability.

Frequently asked questions

What's the difference between tow rating and payload? +
Tow rating is the most weight the vehicle is engineered to pull behind it. Payload is how much weight it can carry in it — GVWR (gross vehicle weight rating) minus curb weight. They're separate limits and both must be satisfied. The catch is that a trailer's tongue weight counts against payload, not tow rating.
What is tongue weight and why does it matter? +
Tongue weight is the downward force the trailer's coupler puts on the hitch — typically 10-15% of the loaded trailer weight for a conventional trailer. It rides on the vehicle, so it consumes payload alongside passengers and cargo. Too little tongue weight causes dangerous trailer sway; too much overloads the rear axle and steals payload.
Can I be under the tow rating but still overloaded? +
Yes — this is the most common towing mistake. A truck rated to tow 9,000 lb might only have ~1,500-2,000 lb of payload. A 7,000 lb trailer at 13% tongue weight is 910 lb on the hitch; add a family and gear and you can blow payload/GVWR while comfortably 'under' the tow number. The calculator checks both so this can't surprise you.
Where do I find these numbers for my vehicle? +
GVWR and tire/loading info are on the driver's door-jamb sticker. Tow rating and curb weight are in the owner's manual or manufacturer towing guide for your exact configuration (engine, axle ratio, cab, drivetrain) — trim differences change them significantly. Use the numbers for your specific vehicle, not a generic model figure.
What about GCWR and the hitch rating? +
GCWR (gross combined weight rating) caps vehicle + trailer together, and the hitch/ball has its own rating — both can bind before tow rating or payload. This calculator covers the two limits people most often miss (tow rating and payload incl. tongue). Always also confirm GCWR and that the hitch class matches the load.
Is this safety advice? +
No. AutoMath is an educational tool. Towing safely depends on correct manufacturer ratings for your exact vehicle, proper weight distribution, brakes, and hitch setup. The output depends entirely on the figures you enter — verify them against your door jamb and owner's manual and consult a professional if unsure.

Related calculators

Why “under the tow rating” isn’t enough: the payload trap.

AutoMath is an educational tool. The numbers above depend entirely on the ratings you provide and are not a safety certification.