Automotive, 4WD, Towing & EV Calculators

Tyres, speedometer, towing, 4WD and EV calculators.

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Tire Size CalculatorCompare tire sizes, check diameter and speedometer impact, and convert metric to inches with…

Speedometer Error CalculatorCheck how a tire size or gear change affects your speedometer accuracy and actual speed with…

EV Charging Cost CalculatorEstimate what it costs to charge your electric vehicle at home or public stations per kWh and…

Two-Stroke Fuel Mix CalculatorCalculate the right petrol to oil ratio for two-stroke engines like 50:1 or 40:1 from your fuel…

All Automotive, 4WD, Towing & EV Calculators (34)

Guide to Automotive Calculators

This hub covers the numbers that change when you modify, load or run a vehicle in Australian conditions: fitting bigger tyres, towing a van within your rig's limits, and working out what an EV or hybrid actually costs to run. It's used by 4WD and caravan owners, DIY mechanics and people cross-shopping diesel, petrol and electric. The catch is that most of these figures interact, so a bigger tyre also throws out your speedo, gearing and diff ratio, and a compliant tow depends on GVM, GCM and tongue weight together rather than any single sticker.

Tyre sizing and fitment

Start with the size calculator or the by-wheel/by-diameter charts to read a marking, then use the comparison visualiser and alternate finder to check a plus-size still clears; wheel offset and 4WD clearance tools confirm it fits the guard and hub.

Tire Size Calculator Tire Size Comparison Visualizer Alternate Tire Size Finder Tire Size Chart by Wheel Size Tire Size Chart by Diameter Wheel Offset & Backspacing Calculator 4WD Tyre Clearance Change Calculator Tire Pressure Change Assistant

Knock-on effects of a tyre change

After sizing, check what the new rolling diameter does downstream: speedometer error tells you the real speed, while diff, crawl and effective gear ratio tools show how it changes drivability and low-range crawl.

Rolling Diameter Calculator Speedometer Error Calculator Effective Gear Ratio Calculator Diff Ratio Calculator Crawl Ratio Calculator

Towing weights and compliance

Use the towing payload, GVM/GCM and 85% rule tools together to confirm the loaded rig stays within its limits, and the tongue weight tool to get the ball-weight balance right before a trip.

Towing Payload Calculator GVM & GCM Compliance Calculator Caravan Tow Safety (85% Rule) Calculator Trailer Tongue Weight Calculator

Fuel, EV and running costs

Compare drivetrains with the diesel/petrol/EV tool, then dig into specifics: fuel consumption and range for a tank, EV range, charge time and charging cost, or the PHEV split if you run both.

Diesel vs Petrol vs EV Running Cost Comparison Fuel Consumption Calculator Fuel Range Calculator EV Range Calculator EV Charge Time Calculator EV Charging Cost Calculator PHEV Electric/Fuel Split Calculator

Ownership costs and maintenance

Estimate the money side with depreciation and lease balloon tools, and stay on top of upkeep with service and tyre-rotation intervals plus coolant freeze-point checks.

Vehicle Depreciation Calculator Lease Balloon Payment Calculator Service Interval Calculator Tyre Rotation Interval Calculator Coolant Freeze Point Calculator

Important calculation notice

These calculators are intended for education, estimation and preliminary checks. Verify all inputs, units, assumptions, material properties and applicable standards. Safety-critical or final engineering designs should be checked by a suitably qualified professional.

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Automotive, 4WD, Towing & EV Calculators

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All Automotive, 4WD, Towing & EV Calculators (34)

Vehicle & Performance18 calculators

Towing, 4WD & Drivetrain6 calculators

Fuel, EV & Running Costs5 calculators

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