EV vs Petrol Calculator

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EV vs Petrol Costs

Compare annual fuel expenses and emissions

Usage

Annual Mileage

Petrol Car

Fuel Efficiency (MPG)

Fuel Price (p/litre)

Electric Car

Efficiency (mi/kWh)

Charging Cost (p/kWh)

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Annual Saving (EV)

Fuel costs are based on user inputs. Home charging is typically 7–15p/kWh; public rapid charging is 40–60p/kWh.

3p/mi

EV Home Charge Cost

15p/mi

Petrol Cost (typical)

1m+

EVs on UK Roads (2024)

Understanding EV Running Costs

Electric vehicles cost significantly less to run than petrol cars in the UK. At home charging rates of 7–15p/kWh, an EV costs about 2–3p per mile, compared to 15p per mile for a petrol car at 140p/litre.

🏠 Plain English Guide

The most useful way to compare EV and petrol cars is pence per mile. A typical petrol car doing 48 MPG at 140p/litre costs about 15p per mile in fuel. An EV charging at home at 15p/kWh (recent off-peak tariffs like Octopus Go) and achieving 3.8 miles per kWh costs about 4p per mile. Over 7,400 miles per year (the UK average), that's £1,110 for petrol versus £296 for EV charging—a saving of £814 per year.

Home Charging Setup: A 7kW wall charger (wallbox) costs £800–1,200 installed. Installation requires a qualified electrician and an EVCP (EV charging point) installation certificate. If your home has a driveway or garage, you can charge overnight at your electricity rate. If you're on a standard tariff (24–25p/kWh), home charging costs about 6–7p per mile. If you're on an off-peak tariff like Octopus Go (7–10p/kWh for 4 hours nightly), charging overnight costs just 2–3p per mile—even cheaper than a petrol car.

Public and Rapid Charging: Public chargepoints (50,000+ across the UK) cost 20–45p/kWh. Rapid chargers (50–150kW, add 200–300 miles in 20–30 mins) typically cost 40–60p/kWh, which works out to 10–15p per mile—still cheaper than petrol but not as cheap as home charging. Most EV owners do 80% of their charging at home and use public chargers only for long trips.

Battery Degradation: Modern EV batteries degrade slowly, typically 3% per year in the first 5 years, then more slowly after. A 60 kWh battery might lose 3–5 kWh per year, but this is barely noticeable in range or performance. Most EV manufacturers guarantee 70–80% of battery capacity after 8 years, and most EVs retain 90% of their original range after 5 years of use. This is one reason used EVs are becoming increasingly attractive—a 5-year-old EV with 70% of original range is still perfectly usable.

Maintenance: EVs have far fewer moving parts than petrol cars (no oil, transmission fluid, spark plugs, or timing belts). Scheduled maintenance is minimal: brake fluid check every 2 years, cooling fluid for the battery pack, and tire rotations. Regenerative braking (recovering energy when slowing down) means brake pads last 2–3x longer. EV owners typically save £500–1,000 per year on servicing versus petrol cars.

Second-Hand EV Buying: Used EVs are a bargain. A 5-year-old EV costs 40–50% of the new price but retains 80–90% of original usable range. Battery health is the key metric—ask for a battery diagnostic report from the dealer. Apps like Plugshare, Zap-Map, and Tesla Supercharger maps show chargepoint availability, so range anxiety is minimal in the UK (chargepoint density is excellent).

Install home charger if possible: 7kW wallbox costs £1,000–1,200 but cuts charging cost to 7–10p/kWh on standard tariffs, or 2–3p/kWh on off-peak rates.
Use off-peak tariffs: Octopus Go, Intelligent Octopus, and similar schemes offer 7–10p/kWh for 4–6 hours nightly. Charge overnight and save 75% on fuel cost.
Slow-charge at home when possible: 7kW wallbox overnight (12 hours) adds 50–60 miles. Fast 22kW chargers (£2,000+) are rarely worth it for home use.
Check chargepoint networks: Download Zap-Map, Plugshare, and your EV's native app to find chargers on long trips.
Buy used EVs: A 5-year-old EV is 40–50% cheaper than new and has lost only 10–15% of range. Battery degradation is slow and predictable.

📊 Technical Reference

EV Efficiency and Well-to-Wheel Analysis: EV efficiency is measured in miles per kWh (or kWh per 100 km). Typical real-world efficiency is 3.5–4.2 mi/kWh depending on car mass, drag coefficient, and driving conditions. A 60 kWh battery achieves 210–252 miles of range. Charging losses (AC-to-battery) are typically 10–15%, so a charger delivering 15 kWh to the battery actually draws 17.6 kWh from the wall at 90% efficiency. Grid-to-wheel efficiency (well-to-wheel for EVs) is approximately 70–75% when accounting for charger losses and UK grid mix. This is still 3–4x better than petrol cars (well-to-wheel ~20–25%).

Battery Degradation Models: Li-ion EV batteries follow a sigmoid degradation curve: rapid initial loss (often 3–5% in first 6 months due to SEI layer formation), then linear degradation of 2–3% per annum for 5–10 years, then slower degradation. Nissan Leaf battery degradation data (2018 cohort) shows ~15% capacity loss after 8 years with intensive fast-charging (e.g., taxi use). Consumer EVs (Teslas, VW ID.4) show 10% loss after 8 years with typical use. Temperature management (thermal conditioning) and avoiding full discharge extend lifespan. Battery manufacturers typically warrant 70–80% capacity after 8 years or 100,000 miles.

Tariff Economics and Load Shifting: The wholesale UK electricity cost is ~£60–100/MWh (6–10p/kWh), while retail rates are 20–25p/kWh for standard tariffs. Off-peak tariffs (7–10p/kWh for 4–6 hour windows) recover closer to wholesale costs because they encourage demand-side response. Vehicle-to-Grid (V2G) with bidirectional chargers (e.g., Nissan Leaf, Hyundai Ioniq 5) can export battery power at 15–20p/kWh, potentially generating £1,000–2,000/year for vehicles with high mileage and regular charging at off-peak times. V2G is emerging but currently requires compatible vehicles and chargers (Wallbox Quasar, ABB Terra 184, Nissan CHAdeMO home charger).

Total Cost of Ownership (TCO): TCO includes purchase price, fuel, maintenance, insurance, road tax, and depreciation. On a 5-year horizon, EVs have higher upfront cost but lower operating costs. Fuel saving: £1,500–2,500/yr. Maintenance saving: £500–1,000/yr. VED saving: £155/yr (EVs are exempt). Company car BIK tax saving: 2% for pure EVs (vs. 25% for petrol) = £2,000–4,000/yr for company car users. After 5 years, a £35,000 EV has depreciated to ~£18,000–20,000, versus a £25,000 petrol car depreciating to ~£14,000–16,000. EVs hold residual value well and the fuel/maintenance savings offset higher purchase cost.

Charging Networks and Commercial Chargepoint Costs: 50,000+ chargepoints across the UK (as of 2024) operated by networks like Pod Point, Instavolt, Tesla Supercharger, Ionity, and BP Pulse. Rapid chargers (50–150kW) cost 40–60p/kWh for non-subscribers, 20–30p/kWh with subscriptions. Typical 20-minute session adds 200–300 miles for £12–25. Monthly subscription plans (£10–20) make fast chargers economic for regular long-distance users. Route planning software (Tesla navigation, Google Maps EV mode) calculates optimal chargepoint stops based on real-time availability and pricing.

Grid Impact and Carbon Intensity: UK electricity carbon intensity (gCO2/kWh) is ~215 g/kWh average (2024), down from 250 g/kWh in 2020. Coal-free days are now common. An EV charged at average grid mix emits 150 gCO2e/km (50% of a petrol car's ~300 gCO2e/km). Charged on off-peak (wind-rich) nights, this falls to 100–120 gCO2e/km. Over lifetime (200,000 km), an EV has 50–60% lower total emissions than a petrol car even accounting for manufacturing (EV battery production is ~200 kg CO2 per kWh, but this is amortized over 1,000 cycles).

Frequently Asked Questions

Is it really cheaper to run an EV?

Yes, significantly. At home charging rates of 15p/kWh, an EV costs about 4p per mile, versus 15p per mile for a 48 MPG petrol car at 140p/litre. That's a saving of £814 per year on 7,400 miles. On off-peak tariffs (7–10p/kWh), EV costs fall to 2–3p per mile—even cheaper. Plus, EVs have no oil changes, fewer brake replacements, and zero servicing costs.

What does it cost to install home charging?

A 7kW wall charger (wallbox) costs £800–1,200 installed. Installation includes electrician labor and an EVCP certificate. Some grants are available (e.g., workplace charging schemes). You'll need a driveway or off-street parking. Many renters can't install home chargers, so they rely on workplace or public chargepoints.

Can I charge an EV at work?

Many workplaces now install chargepoints. If your employer has parking and a low-demand electricity supply, you can typically charge free or at cost (5–10p/kWh). Workplace charging is ideal if your commute is 20–50 miles—you can top up during the day and avoid home charging costs entirely. Check with your employer's facilities team.

How long does charging take?

Home charging (7kW) adds 25–30 miles per hour, so a full 10-hour overnight charge adds 250–300 miles. Public fast chargers (22kW) add 100 miles in 30 mins. Rapid chargers (50–150kW) add 200–300 miles in 20–30 minutes. Most owners charge overnight at home and use public chargers only on road trips.

Is public charging expensive?

Public chargepoints cost 20–45p/kWh depending on charger speed and network. A 20-minute rapid charge might cost £12–25 and add 200–300 miles. For occasional long trips, this is acceptable. For daily commuting, home charging (7–15p/kWh) is much cheaper. Most EV owners do 80% of charging at home and use public chargers only for holidays and long trips.