Petrol vs Diesel vs Hybrid vs Electric — Which Is Cheapest to Run?

Choosing between petrol, diesel, hybrid, and electric isn't just about what's greenest or trendiest — for most buyers, it comes down to cost. And the cheapest option depends almost entirely on how you drive.

Here's a straightforward comparison based on real-world figures for a typical UK driver covering 8,000 to 12,000 miles a year.

The running costs that actually matter

When people compare fuel types, they usually focus on the price at the pump (or the plug). But fuel or energy cost is only one piece of the picture. The true running cost of a car includes:

• Fuel or energy — what you pay per mile to move
• Road tax (VED) — annual vehicle excise duty
• Insurance — premiums vary significantly by fuel type
• Servicing and maintenance — some drivetrains cost far more to maintain
• Depreciation — the biggest cost of all, and it varies by fuel type

Let's break each one down.

Fuel and energy costs per mile

This is where the differences are most dramatic. Based on average UK fuel prices in early 2026:

• Petrol — at roughly 140p/litre and 40mpg real-world economy, that's approximately 16p per mile
• Diesel — at roughly 148p/litre and 50mpg real-world economy, that's approximately 13p per mile
• Full hybrid — real-world economy around 50-55mpg on petrol, roughly 11-12p per mile
• Plug-in hybrid (PHEV) — 2-3p per mile on electric, 16-18p per mile on petrol. Your real cost depends entirely on how often you charge
• Battery electric (BEV) — home charging costs roughly 3-5p per mile. Public rapid charging is more like 8-12p per mile

The raw fuel cost favours electric by a wide margin. A driver covering 10,000 miles a year would spend roughly £1,600 on petrol, £1,300 on diesel, or £400 on home-charged electricity.

You can check any car's fuel economy data for free using Free Plate Check — we show real-world figures alongside official numbers.

Road tax (VED)

Road tax rates changed significantly for electric vehicles from April 2025. Here's where things stand in 2026:

• Petrol and diesel — standard rate of £190/year for most cars registered after April 2017. First-year rates vary by CO2 emissions and can be significantly higher for polluting models.
• Hybrid — same standard rate as petrol and diesel. Some older hybrids registered before April 2017 benefit from lower rates based on emissions.
• Electric — now £190/year at the standard rate (previously exempt). Still exempt from the expensive car supplement that adds £410/year for cars listing over £40,000 new.

Road tax is largely a level playing field now for newer cars. Our guide to car tax rates in 2026 has the full breakdown, or you can check any car's tax status for free.

Insurance

Insurance costs vary enormously by driver, but fuel type does influence which group a car falls into:

• Petrol — generally the lowest insurance groups for mainstream models
• Diesel — typically one to three groups higher than the equivalent petrol version
• Hybrid — similar to petrol equivalents, sometimes slightly higher due to more complex technology
• Electric — often in higher insurance groups due to expensive battery repairs. Premiums are coming down as insurers gain experience, but EVs still tend to cost more to insure

For a typical family car, the insurance difference between petrol and electric might be £100-£300 per year. Our guide to car insurance groups explained covers how the system works.

Servicing and maintenance

This is where electric cars genuinely shine:

• Petrol — annual service typically £150-£250. Regular items include oil changes, spark plugs, air filters, cambelt replacement (every 4-5 years on some engines)
• Diesel — £180-£300 per service. Diesel particulate filter (DPF) issues can cost £1,000+ to resolve. Dual-mass flywheel replacement on some models is £800-£1,500
• Hybrid — similar to petrol for the engine, plus occasional battery health checks. Generally reliable, though battery replacement (rare) is expensive
• Electric — minimal servicing. No oil changes, no exhaust system, no clutch, no cambelt. Expect to pay £80-£150 for an annual check. Brake pads last much longer thanks to regenerative braking

Over five years, the servicing difference between a diesel and an electric car can easily reach £2,000-£3,000.

Depreciation — the silent cost

Depreciation is typically the largest cost of car ownership, and it varies significantly by fuel type:

• Petrol — steady, predictable depreciation. Well-understood market.
• Diesel — faster depreciation in recent years due to falling demand, ULEZ restrictions, and negative press. Diesel values have stabilised somewhat but remain weaker than petrol for smaller cars.
• Hybrid — strong residual values, particularly for Toyota/Lexus self-charging hybrids. Market confidence is high.
• Electric — historically volatile. Early EVs depreciated rapidly as battery technology improved. Newer models with longer ranges are holding value better, but rapid model cycles still create risk.

If you're buying used, depreciation works in your favour — especially for electric cars where someone else has absorbed the steepest drop. You can check any car's current market value for free to see where it sits.

A worked example: Ford Puma petrol vs mild hybrid

Let's put real numbers on this. The Ford Puma is one of the UK's best-selling cars and comes in both 1.0 EcoBoost petrol and 1.0 EcoBoost Hybrid (mild hybrid) versions.

For a driver covering 10,000 miles a year:

The mild hybrid saves around £170 per year in this scenario — mainly through better fuel economy in town driving. Over three years that's roughly £500, which may or may not offset the higher purchase price of the hybrid version.

The savings become more significant with a full hybrid or plug-in hybrid, but so does the price premium.

When does diesel still make sense?

Despite the negative headlines, diesel remains a solid choice in specific circumstances:

• High annual mileage (above 12,000-15,000 miles) — the fuel cost saving per mile adds up
• Predominantly motorway driving — diesel engines are at their most efficient at steady speeds
• Towing — diesel torque makes towing easier and more fuel-efficient
• Larger vehicles — SUVs and estate cars often suit diesel better due to the weight advantage

If you're doing short urban trips, diesel is almost certainly the wrong choice. DPF issues from low-speed driving can be expensive, and you won't benefit from the efficiency advantage.

Check whether a car you're considering is ULEZ compliant before buying — older diesels (pre-Euro 6, typically pre-September 2015) face daily charges in London's ULEZ zone.

The bottom line: which fuel type is cheapest?

For the average UK driver covering 8,000-10,000 miles a year, mostly around town:

1. Full hybrid offers the best balance of low running costs and reasonable purchase price
2. Petrol remains the cheapest to buy and simplest to own
3. Electric is cheapest per mile but the higher purchase price takes years to recoup
4. Diesel is only cost-effective for high-mileage drivers

There's no universal answer — it depends on your mileage, driving style, and how long you plan to keep the car. The best starting point is to check the actual specs, fuel economy, and running costs for any car you're considering.

Run a free plate check to see fuel type, CO2 emissions, tax costs, and more for any UK vehicle — then make your decision based on real numbers, not assumptions.