PHEV Electric/Fuel Split Calculator
See how much of a plug-in hybrid trip runs on battery versus petrol. Enter the trip distance, your usable EV-only range and your petrol economy, and the tool splits the journey into electric and petrol kilometres, the fuel used, and the percentage of the trip driven on electricity.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the total trip distance in kilometres.
- Enter your PHEV's usable EV-only range (the real range on the day, not the brochure figure) and your petrol economy in L/100km.
- Optionally add the EV consumption in kWh/100km to also see the electricity used, then read the petrol used (emphasised) and the electric share.
How it works
The battery covers the electric distance = min(trip distance, EV-only range). Anything beyond the EV range runs on the engine, so petrol distance = trip − electric distance. Petrol used = petrol distance ÷ 100 × petrol economy, and if you supply an EV consumption the electricity used = electric distance ÷ 100 × consumption. The electric share is the electric distance as a percentage of the whole trip.
Worked example
Worked example. On a 100 km trip with a 50 km EV range and 6 L/100km economy, the first 50 km are electric and the remaining 50 km use petrol: 50 ÷ 100 × 6 = 3 L, so 50% of the trip is electric. A shorter 40 km trip stays entirely on battery — 0 L of petrol and 100% electric.
Common mistakes
- Using the manufacturer's rated EV range rather than the real usable range — cold weather, heating, hills and highway speeds can cut it substantially.
- Assuming a flat PHEV battery means the car stops — it simply reverts to hybrid/petrol running, which this split reflects.
- Forgetting that a single figure ignores mid-trip charging or regeneration, which would shift more of the journey back onto electricity.
Frequently asked questions
What EV range should I enter?
Use the range you can realistically achieve on a full charge under your typical conditions. Winter heating, air-conditioning, highway speeds and hilly terrain all reduce it below the official WLTP/rated number.
Does this include the cost of the petrol and electricity?
No — this tool gives the physical split of distance, fuel and energy. To compare running costs, take the litres and kWh here and multiply by your local fuel price and electricity tariff, or use a running-cost comparison calculator.
Related tools
- Fuel Consumption Calculator
- EV Range Calculator
- Road Trip Fuel Stop Calculator
- Diesel vs Petrol vs EV Running Cost Comparison
- Fuel Range Calculator
- Two-Stroke Fuel Mix Calculator
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Tip: Enter any known values to calculate the remaining results.
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