What this site publishes, where every number comes from, what happens when something here turns out to be wrong, and the errors already corrected.
Last reviewed: 2026-08-26
Who writes this
TowCapacityCalc is written and edited by Imtinan Farooq, Editor, TowCapacityCalc. One named person is accountable for every page on this site. There is no anonymous “editorial team” standing in for a byline, and no invented expert names, fabricated credentials or borrowed certifications.
That accountability is the reason the corrections log further down this page exists. If something here is wrong, there is one person to hold to it.
Where the numbers come from
This site reconciles published engineering and legal figures — its job is to show which limit actually binds, not to invent the limits. So the provenance rules are strict.
Ratings come from the manufacturer. Tow ratings, payload, GVWR, GCWR and axle ratings are taken from published towing guides and owner’s manuals, and the configuration they describe is stated — because a headline tow rating almost always belongs to one specific cab, bed, axle and engine.
Legal claims cite an official publisher. State legislature or state code, DOT, DMV, or department of public safety. Aggregators such as Justia, FindLaw and Casetext, law-firm marketing pages, RV forums and towing blogs are not acceptable sources for a legal claim: a summary of a summary is how a wrong statute number spreads.
The citation travels with the claim. Each state equipment rule carries its own statute citation and official link on the page where it appears, rather than sitting in a source list at the bottom. Any single sentence can be checked against the exact section it came from.
That standard is enforced automatically rather than by good intentions: a source check runs before every deployment and fails the build on a legal claim whose citation is not an official publisher. The state equipment rules currently stand at 138 cited rules across 49 states, each with its statute and official link, last read end to end on 2026-08-21.
When the answer is not known
No entry is better than a guessed one. Where an official source could not be found for a specific state requirement, the page says so rather than filling the gap with a plausible-sounding figure or a number borrowed from a neighbouring state.
12 of the 150 possible state-level entries are deliberately left unrecorded for that reason, and they read as needing verification because that is the true state of the record. A blank is honest; an invented citation is a trust failure.
The same rule governs arithmetic. Curb weight is never derived by subtracting a published maximum payload from a published GVWR: those two figures describe different configurations of the vehicle, and the result is nonsense. Where a figure cannot be derived soundly, the page asks for the number off your own door jamb instead.
What every towing page must do
Towing advice affects safety, so each guide and calculator is expected to leave you better able to check your own vehicle — not more willing to trust a single advertised tow rating.
Name which rating is in play: tow rating, payload, GVWR, GAWR, GCWR or hitch load.
State that the door-jamb label and owner’s manual override any example here. Those are the ratings that legally apply.
Use loaded trailer weight — never dry weight — for tongue weight, pin weight and GCWR.
Keep educational planning ranges visibly separate from manufacturer limits and legal requirements.
Send you to a scale when the estimated margin is small.
Say when a technique is common practice rather than manufacturer-published. Where a widely repeated method appears in no manual, the page says so instead of passing it on with borrowed authority.
Corrections
Specifications and statutes change, and research sometimes overturns something already published here. When that happens the page is corrected and the correction is recorded below — including what the page used to say, so the record is auditable rather than quietly rewritten.
This log carries substantive corrections only: cases where a fact published here was wrong or unsafe, and a reader acting on it would have been misled. Copy edits, redesigns and new content are not listed, because a log padded with those stops meaning anything.
Trailer sway advice, four pages
Was: That the brake controller's manual lever is the correct tool for pulling a swaying trailer straight.
Now: The manual lever is for setting gain during trailer setup, not for correcting sway. The advice traced to a real source — Redarc describes its lever as being for exactly that use — but a vehicle manufacturer names the practice and warns against it, and the vehicle manufacturer governs. One stale mention survived in an image caption and was corrected the same day.
Settled by: Ford F-150 owner's manual: "Misuse, such as application during trailer sway, could cause instability of trailer or tow vehicle."
Trailer hitch pillar, 7-way wiring
Was: A 7-way RV blade colour table, telling readers to "work by colour".
Now: Colour is the unreliable part. Three manufacturer sources give three different colour maps for the same connector and only two entries survive all three — white for ground, blue for brakes. Two collisions are dangerous: black is battery charge to one maker and brake output to another; red is 12 V power to one and stop-and-left-turn to another. A single current manual even contradicts itself between its 4-way and 7-way pages. The guide now tells readers to identify pins by function and test, not by colour.
Settled by: Jayco, Big Tex and Curt wiring documentation, compared side by side
Best SUVs for Towing
Was: Tow ratings and dimensions that were substantially wrong — and every error ran the same direction, flattering the vehicle.
Now: Corrected against manufacturer towing guides: Suburban/Yukon XL 8,300 → 8,200 lb; Expedition MAX 9,300 → 9,000 lb (9,300 is the short-wheelbase car); Grand Cherokee 7,200 → 6,200 lb (the 5.7L HEMI is no longer offered); Explorer 5,600 → 5,000 lb (5,600 was the 2024 3.0L EcoBoost); Sequoia understated at 9,000 → up to 9,520 lb. Three wheelbase figures were a full generation out of date.
Settled by: GM, Ford, Jeep and Toyota published towing guides
State law citations, six pages
Was: Six state pages cited Justia or FindLaw as their legal source — a summary of a statute standing in for the statute.
Now: Three were replaced with official sources: Idaho and Wyoming already carried the legislature's own page alongside the aggregator, so the aggregator was redundant; Tennessee, which does not publish its code in full text on a .gov host, now cites the Tennessee Highway Patrol's own trailer requirements page. Arkansas, Mississippi and New Mexico still stand, because for those three the aggregator is the only statute source on the record — recorded openly rather than quietly dropped.
Settled by: State legislature and department of public safety publications
Towing calculator, GCWR check
Was: The combined-weight calculation counted tongue weight twice, making the GCWR margin look smaller than it was.
Now: Tongue weight is counted once, where it belongs — in the tow vehicle's loaded weight.
Settled by: Internal arithmetic review
How updates happen
Pages are revisited when calculator behaviour changes, when a manufacturer publishes new figures, when a statute is amended, when a reader reports unclear wording, or when search data shows a page is not answering the question behind the query.
Trailer brakes, state towing laws, payload overload and fifth-wheel pin weight get stricter review than the rest, because a wrong shortcut in those four creates an unsafe setup rather than an inconvenient one.
Model-year data is re-checked against the manufacturer’s current towing guide rather than carried forward, since ratings move between years and engines are discontinued mid-generation.
What is not published here
No invented vehicle limits. No manufacturer tables copied without the configuration they describe. No legal advice offered as a substitute for an official state source. No claim that a hitch, airbag, helper spring or any other device raises a manufacturer rating — those change how a vehicle rides, not what it is rated to carry.
Where a setup depends on trim, axle ratio, cab, drivetrain, package, wheelbase, tyre or hitch class, the page names which rating still needs verifying against the vehicle itself.
What the calculators do not do
The tools apply standard towing arithmetic to the values you enter. There is no proprietary model and no hidden adjustment. They do not read ratings from a VIN, registration or plate. They do not measure anything — a tongue weight from a percentage is an estimate, and a scale ticket is a measurement. They do not model heat, grade, altitude, wind, tyre condition or brake condition.
Results are estimates for planning. Door-jamb labels, owner’s manuals, hitch labels, tyre ratings and scale weights are the figures that govern before you tow.
Report an error
If you find an outdated rating, a broken or non-official source, or a calculator assumption that does not hold, please report it with the vehicle configuration, the source URL and the page that needs review. Corrections affecting safety are prioritised over everything else, and substantive ones are added to the log above.