Litres consumed per 100 kilometres; lower is better. Standard metric efficiency unit.

Energy lost deforming tires as they roll. Low-pressure or wide tires raise it.

Automotive Calculators

Towing Comparison Calculator

2026-09-27 6 min

Tow-rating and payload gaps between two trucks or SUVs.

Tow Rating Difference (B-A): 2500 lb
Payload Difference (B-A): 300 lb

Calculator

Tow Rating — A(lb)

Tow Rating — B(lb)

Payload — A(lb)

Payload — B(lb)

Results update live as you type

Live statistics

Tow Rating Difference (B-A)

2500 lb

Payload Difference (B-A)

300 lb

Results

Optimal

Tow Rating Difference (B-A)

2500lb

Payload Difference (B-A)

300lb

Planning estimate from standard automotive formulas. Validate with dyno, timeslip or datalog data when precision matters.

Visualizations

Results overview

2,500Tow Rating Difference

300Payload Difference

Tow Rating Difference (B-A) vs. Tow Rating — A

Tow Rating Difference (B-A)

2,500lb

08,000

Formula

Simple rating deltas that frame which truck works harder with margin.

Tow diff = towB - towA; payload diff = payloadB - payloadA

Alternative Form

Confirm GCWR, GVWR and tongue share — ratings interact

Variables

Symbol	Name	Unit	Description
dTow	Tow delta	lb	Rated trailer gap
dPay	Payload delta	lb	Cargo-plus-tongue gap

Explanation

Tow rating sets the trailer; payload often limits first via tongue weight — check both gaps.

Step-by-Step Calculation

Follow each step to understand how the result is calculated from your inputs.

Step 1

Record the inputs.

Tow Rating — A:5000 lb

Tow Rating — B:7500 lb

Payload — A:1500 lb

Payload — B:1800 lb

Result: 4 inputs ready

Step 2

Apply the formula.

Tow diff = towB - towA; payload diff = payloadB - payloadA

Result: Primary result = 2500 lb

Step 3

Read every derived output.

Tow Rating Difference (B-A):2500 lb

Payload Difference (B-A):300 lb

Result: Tow Rating Difference (B-A) = 2500 lb

Final Answer

2500

Worked Examples

See how the calculator works with different scenarios.

Scenario

Midsize versus full-size truck.

Inputs

A:5,000 tow / 1,500 pay

B:7,500 tow / 1,800 pay

Calculation

Tow +2,500; payload +300

Result

+2,500 lb tow, +300 lb payload.

Interpretation

B tows a bigger trailer class with more tongue headroom.

Understanding Your Result

Your Result: Tow Rating Difference (B-A): 2500 lb

What This Means

Rated capability gap between two tow vehicles.

Why It Matters

Margin is safety — bigger gaps mean easier, sway-resistant towing.

Professional Interpretation

Treat the primary result as a planning estimate, then validate on a dyno, at the track, or with logged sensor data. If measured numbers disagree by more than ~10%, re-check inputs (units are the usual culprit) before changing parts.

Recommendations

•Double-check units on every input before trusting the result
•Compare against the worked example below to sanity-check magnitude
•Validate with measured data (dyno, timeslip, datalog) when it matters

Learn — fuel economy, deeply

Towing comparison stacks rated trailer and cargo gaps.

1 · Where the gallon goes (energy path)

Engine heat

60–70% lost

Coolant + exhaust carry most energy away. Hybrids recover some via Atkinson cycle + regen.

Driveline

5–15% lost

Transmission, differential, accessories. CVTs and 8–10 speed autos lose less.

Aero drag

∝ v²

Doubles from 55→78 mph. Roof boxes hurt more than trunks.

Rolling + brakes

10–20%

Tires, weight, stops. Regen braking (hybrid/EV) reclaims city braking energy.

4 · Measure like a pro (the 3-tank protocol)

Fill to first click at the same pump, record the odometer (Tank 0).
Drive normally for 2–3 tanks; always refill to first click at the same pump.
MPG = total miles ÷ total gallons across all tanks — averaging kills pump-click noise.
Cross-check with the trip computer; a persistent >10% gap means the computer needs calibration — or the car needs service.
Log with an OBD-II dongle for per-trip MPG if you want to isolate commute vs. highway behavior.

Practical Tips

•Payload usually limits before tow rating
•Budget 10-15% tongue weight
•Compare same cab/axle configs

Common Mistakes

Mixing units (inches with mm, psi with kPa)

Convert every input to the unit shown on its field before calculating.

Trusting a single output blindly

Cross-check with the worked example and, when it matters, a dyno or datalog.

Assumptions

This calculator makes the following assumptions to provide estimates:

Steady-state model: Formulas assume stabilized conditions; transients, heat soak and traction limits are excluded.

Standard factors: Empirical constants (BSFC, VE, drivetrain loss) use typical values — your combination may differ.

Limitations

Be aware of these limitations when using this calculator:

Estimate, not measurement: Predictions carry real-world scatter of roughly ±5–15% depending on the model.

No transient effects: Shift time, wheelspin, spool lag and heat soak are not modeled here.

Frequently Asked Questions

Answers to common questions about this calculator.

Which matters more, tow or payload?

Both — tow caps the trailer, payload caps tongue plus cargo. Payload binds first on many half-tons.

Can I exceed ratings if the gap is small?

No — ratings are legal and engineering limits. Buy the bigger gap instead.

Related Calculators

Explore more calculators related to this topic.

Related Guides

Deepen your understanding with these educational resources.

Automotive Guides

Build planning, measurement protocol and validation how-tos

Glossary

Technical terms used in mortgage calculations explained in plain language.

MPG: Miles per gallon. Distance travelled per gallon of fuel; higher is better. US gallon = 3.785 L.
L/100 km: Litres consumed per 100 kilometres; lower is better. Standard metric efficiency unit.
MPGe: Miles per gallon-equivalent. EV metric: miles travelled on 33.7 kWh (energy of 1 gal of gasoline).
CAFE: Corporate Average Fuel Economy — US fleet-average efficiency standard enforced by NHTSA.
Rolling resistance: Energy lost deforming tires as they roll. Low-pressure or wide tires raise it.
Aerodynamic drag: Air resistance growing with the square of speed — why highway MPG falls fast above 60 mph.
Hypermiling: Driving techniques (coasting, steady speed, anticipation) that maximise real-world MPG.
OBD-II: On-board diagnostics port. Scanners and dongles read live MPG, fuel trim and fault codes.

Authoritative References

Trusted sources and standards referenced by this calculator.

EPA — FuelEconomy.gov DOE — Fuel-Efficient Driving Tips NHTSA — Driving Safety & Efficiency SAE International — Fuel Economy Standards Consumer Reports — MPG Truth IRS — Standard Mileage Rates

Applicable Standards

EPA Fuel Economy Testing (40 CFR Part 600)CAFE — Corporate Average Fuel Economy Standards (NHTSA)WLTP — Worldwide Harmonised Light Vehicle Test ProcedureSAE J1321 / J1711 — Fuel consumption test proceduresISO 2575 — Road vehicles symbols & efficiency markings

Was This Calculator Helpful?

Report Issue

Page Information

Last Updated:

2026-09-27

Version:

2.0.0

References:

License:

Free to use for educational and professional purposes.