Towing Capacity Calculator
Estimate trailer limits from vehicle payload and entered ratings. Compare the result with your vehicle, trailer and hitch specifications before towing.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Compare an estimated trailer limit with the ratings you enter. All weight inputs use pounds (lb). The hitch rating here means maximum trailer weight. This is only a partial check: also verify tongue-weight limits, GVWR, GCWR, axle and tire ratings, loading and the vehicle/hitch maker’s instructions before towing.
Worked example
calculated with the default values below
Vehicle gross vehicle weight rating 7,000 lb · Curb weight 5,200 lb · Passengers and other cargo load 600 lb · Manufacturer tow rating 9,000 lb · Loaded trailer weight 6,000 lb · Tongue weight 12 % · Hitch maximum trailer-weight rating 10,000 lb Payload capacity 1,800 lb · Payload remaining 1,200 lb · Tongue weight 720 lb · Max trailer weight for your load 9,000 lb · Comparison with entered limits Within the entered ratings
General background references
Disclaimer
These calculators give estimates for general information only. Real fuel consumption, performance and range vary with driving style, load, terrain, temperature and vehicle condition. Do not rely on these results for towing limits, payload or braking decisions — use the rating plate of your vehicle.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
L = min(T, H, { P ÷ (q ÷ 100), q > 0; 0, q = 0 }); v = 𝟙[W ≤ L ∧ q × W ÷ 100 ≤ P]
- L
- Maximum trailer weight
- W
- Trailer weight
- T,H
- Tow rating; hitch rating
- P
- Remaining payload
- q
- Tongue weight (%)
- v,𝟙[x]
- Verdict (1 pass, 0 fail); indicator: 1 if x holds, else 0
P = max(0, GVWR − curb weight − passengers); q = 0 makes the payload-based limit 0.
Frequently asked questions
Does the result confirm that my trailer is safe to tow?
No. It is a partial comparison of the entered ratings and payload estimate. Check the vehicle’s GVWR and GCWR, axle and tire limits, hitch and tongue-weight ratings, loaded weights, and the vehicle and hitch manufacturers’ instructions.
What does the hitch rating field mean?
In this calculator it means the hitch’s maximum trailer-weight rating. It does not represent the hitch’s separate maximum tongue-weight limit, which must also be checked against the vehicle and hitch labels or manuals.