AtlasCalcsUtility Calculation Suite
Automotive Calculators

Off-Road Ground Clearance Calculator

2026-09-27 6 min

Lifted running clearance from stock height, suspension lift, tire gain and sag.

Running Clearance
10.50 in
Net Gain
2.00 in

Calculator

Stock Clearance(in)
in
Suspension Lift(in)
in
Tire Diameter Increase(in) Help
in

Diameter growth vs stock

Loaded Sag(in) Help
in

Squat under gear + armor

Results update live as you type

Live statistics

Running Clearance

10.50 in

Net Gain

2.00 in

Results

Optimal

Running Clearance

10.50in

Net Gain

2.00in

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

Visualizations

Results overview

10.5Running Clearance
2Net Gain

Running Clearance vs. Stock Clearance

Running Clearance

10.5in
418

Formula

Lift adds fully; tire diameter adds only half (radius); loaded sag subtracts.

Clearance = stock + lift + tire_gain/2 - sag

Variables

SymbolNameUnitDescription
G/2Tire radius gaininOnly half the diameter lifts the diff

Explanation

8.5 + 2 + 0.5 - 0.5 = 10.5 in — the diff (lowest point) rises with radius, not diameter.

Step-by-Step Calculation

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

Step 1

Record the inputs.

Stock Clearance:8.5 in
Suspension Lift:2 in
Tire Diameter Increase:1 in
Loaded Sag:0.5 in
Result: 4 inputs ready
Step 2

Apply the formula.

Clearance = stock + lift + tire_gain/2 - sag
Result: Primary result = 10.50 in
Step 3

Read every derived output.

Running Clearance:10.50 in
Net Gain:2.00 in
Result: Running Clearance = 10.50 in
Final Answer
10.50

Worked Examples

See how the calculator works with different scenarios.

Scenario

Stock 8.5-in SUV with armor sag.

Inputs

Stock:8.5 in
Lift:2 in
Tires:+1 in
Sag:0.5 in

Calculation

8.5 + 2 + 0.5 - 0.5 = 10.5

Result

10.5 in running clearance.

Interpretation

+2.0 in net gain over stock.

Understanding Your Result

Your Result: Running Clearance: 10.50 in

Typical range: Stock 7-9 in; lifted 10-13 in; portals/long-arm 14 in+.

What This Means

Lowest-point height ready to roll, loaded as driven.

Why It Matters

Clearance decides which rocks and ruts pass under the diffs without contact.

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

Running clearance stacks three mods — lift, tire radius and loaded sag — on top of stock height.

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)

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

Practical Tips

  • •Measure at the diff pumpkin — the low point
  • •Armor weight eats lift via sag
  • •Tires give clearance gears cannot

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.

Why does tire gain count only half?
Ground clearance rises with axle-center height, which is the tire radius — half the diameter. A 2-in taller tire lifts diffs 1 in.
Does a body lift add clearance?
No — body lifts raise sheet metal for bigger tires but leave frame and diffs where they were.

Related Calculators

Explore more calculators related to this topic.

Related Guides

Deepen your understanding with these educational resources.

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.

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?

Page Information