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

Trailer Weight Distribution Calculator

2026-09-27 6 min

Axle and per-axle trailer loads from gross weight, tongue weight and axle count.

Total Axle Load: 6200 lb
Per Axle: 3100 lb

Calculator

Gross Trailer Weight(lb)

Tongue Weight(lb)

Trailer Axles

Results update live as you type

Live statistics

Total Axle Load

6200 lb

Per Axle

3100 lb

Results

Optimal

Total Axle Load

6200lb

Per Axle

3100lb

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

Visualizations

Results overview

6,200Total Axle Load

3,100Per Axle

Per Axle vs. Gross Trailer Weight

Per Axle

3,100lb

08,000

Formula

Splits the trailer between hitch and running gear, then per axle for rating checks.

Axle load = gross trailer - tongue

Alternative Form

Per axle = axle load / axle count (compare with GAWR and tire ratings)

Variables

Symbol	Name	Unit	Description
n	Axles		Load-sharing running gear

Explanation

Tires, bearings and axle ratings see per-axle load — the number that actually breaks parts.

Step-by-Step Calculation

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

Step 1

Record the inputs.

Gross Trailer Weight:7000 lb

Tongue Weight:800 lb

Trailer Axles:2

Result: 3 inputs ready

Step 2

Apply the formula.

Axle load = gross trailer - tongue

Result: Primary result = 3100 lb

Step 3

Read every derived output.

Total Axle Load:6200 lb

Per Axle:3100 lb

Result: Per Axle = 3100 lb

Final Answer

6200

Worked Examples

See how the calculator works with different scenarios.

Scenario

Travel trailer axle check.

Inputs

GTW:7,000 lb

Tongue:800 lb

Axles:2

Calculation

Axle total 6,200; 3,100 each

Result

3,100 lb per axle.

Interpretation

Needs 3,500-lb axles and matching ST tires with margin.

Understanding Your Result

Your Result: Total Axle Load: 6200 lb

What This Means

What each trailer axle and tire set actually carries.

Why It Matters

Sizes axles, springs and tires — and validates weight-distribution hitch setup.

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

Trailer weight splits three ways: tongue, axles, and (with WD) restored truck front axle.

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

•Set WD hitch by front-fender height recovery
•Re-tune WD after loading changes
•Grease and inspect spring bars yearly

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.

Do I need a weight distribution hitch?

Generally when tongue exceeds ~500 lb or 10% of tow rating — it restores front-axle steering weight.

How do I check axle ratings?

Compare per-axle load against the axle GAWR tag and the combined tire rating per axle.

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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.
Weight distribution hitch: Spring-bar hitch that levers tongue weight forward onto the truck front axle and back onto trailer axles.

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

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Page Information

Last Updated:

2026-09-27

Version:

2.0.0

References:

License:

Free to use for educational and professional purposes.