Electric vs Petrol Car Cost Calculator UK 2026 — True Running Costs

Electric cars have higher purchase prices but lower running costs. Here’s how to calculate which is actually cheaper for you.

Quick Comparison: £30,000 Car Over 5 Years

Cost	Petrol	Electric
Purchase price	£30,000	£35,000
Fuel/electricity (10k miles/yr)	£8,750	£2,625
Road tax	£950	£0*
Servicing	£2,500	£1,250
Insurance	£3,750	£4,500
ULEZ savings**	£0	£6,250
5-Year Total	£45,950	£43,625
Annual Cost	£9,190	£8,725

*£0 until April 2025, then standard rates apply **If driving daily in ULEZ

Electric is £2,325 cheaper over 5 years despite costing £5,000 more to buy.

Fuel vs Electricity Costs

Cost Per Mile Comparison

Vehicle Type	Efficiency	Fuel Cost	Cost Per Mile
Petrol (small)	45 mpg	£1.40/L	14p
Petrol (medium)	35 mpg	£1.40/L	18p
Petrol (SUV)	28 mpg	£1.40/L	23p
Diesel (medium)	50 mpg	£1.45/L	13p
Electric (home)	3.5 mi/kWh	12p/kWh	3.4p
Electric (public)	3.5 mi/kWh	65p/kWh	19p

Annual Fuel Costs by Mileage

Annual Miles	Petrol (18p/mi)	EV Home (3.5p/mi)	Saving
5,000	£900	£175	£725
8,000	£1,440	£280	£1,160
10,000	£1,800	£350	£1,450
12,000	£2,160	£420	£1,740
15,000	£2,700	£525	£2,175
20,000	£3,600	£700	£2,900

Electricity Cost by Charging Method

Charging Type	Cost Per kWh	Cost Per Mile	For 250 Miles
Home (standard rate)	12p	3.4p	£8.50
Home (EV tariff)	7.5p	2.1p	£5.25
Home (Octopus Go)	7.5p	2.1p	£5.25
Workplace (free)	£0	£0	£0
Public slow (7kW)	40p	11p	£27.50
Public rapid (50kW+)	65p	19p	£47.50

Road Tax (VED) Comparison

2026/27 Rates

Vehicle	First Year	Years 2+
Petrol (avg CO2 130g/km)	£240	£190
Diesel (avg)	£260	£190
EV (pre-Apr 2025 registered)	£0	£0
EV (post-Apr 2025)	£0	£190

5-Year Road Tax Cost

Vehicle	5-Year Cost
Petrol (from new)	£1,000
EV (registered 2024)	£0
EV (registered 2026)	£760

EV road tax exemption ends April 2025 for new registrations.

Insurance Costs

Typical Insurance Comparison

Factor	Petrol	Electric
Average premium	£550/year	£680/year
Why higher for EV	Repair costs, battery
Gap closing?	Yes, rapidly

EV insurance is 15-25% higher on average, but the gap is narrowing.

Servicing and Maintenance

Annual Service Costs

Vehicle	Annual Service	Why
Petrol	£400-600	Oil, filters, spark plugs
Diesel	£450-650	Oil, filters, DPF
Electric	£150-300	Brakes, tyres, coolant

Maintenance Differences

Item	Petrol/Diesel	Electric
Oil changes	Every 10-12k miles	None
Spark plugs	Replace periodically	None
Exhaust system	Can fail	None
Brake pads	Regular replacement	Last longer (regen braking)
Gearbox	Can fail	None (single speed)
Clutch	Wears out	None
Battery	12V standard	Main battery warranty 8 years

5-Year Maintenance Estimate

Vehicle	5-Year Cost
Petrol	£2,500
Diesel	£2,800
Electric	£1,250

Total Cost Calculator by Scenario

Scenario 1: 8,000 Miles/Year, Home Charging

5-Year Costs	Petrol £25k	EV £30k
Purchase (less trade-in)	£15,000	£18,000
Fuel/electricity	£7,200	£1,400
Road tax	£950	£0
Insurance	£2,750	£3,400
Servicing	£2,500	£1,250
Total	£28,400	£24,050
EV Saving		£4,350

Scenario 2: 15,000 Miles/Year, Some Public Charging

5-Year Costs	Petrol £30k	EV £35k
Purchase (less trade-in)	£18,000	£21,000
Fuel/electricity	£13,500	£3,500
Road tax	£950	£0
Insurance	£2,750	£3,400
Servicing	£2,500	£1,250
Total	£37,700	£29,150
EV Saving		£8,550

Scenario 3: 5,000 Miles/Year, City Driver (ULEZ)

5-Year Costs	Petrol £20k	EV £25k
Purchase (less trade-in)	£12,000	£15,000
Fuel/electricity	£4,500	£875
Road tax	£950	£0
Insurance	£2,750	£3,400
Servicing	£2,500	£1,250
ULEZ charges (250 days/yr)	£15,625	£0
Total	£38,325	£20,525
EV Saving		£17,800

When NOT to Go Electric

EV May Not Be Cheaper If:

Situation	Why
No home charging	Public charging expensive
Very low mileage	Savings don’t offset price premium
Rural with no infrastructure	Charging access issues
Tow heavy loads frequently	Range impact
Keep cars 10+ years	Battery degradation concerns

Break-Even Calculator

EV Premium	Annual Mileage Needed to Break Even
£3,000	~5,000 miles/year
£5,000	~8,000 miles/year
£7,500	~12,000 miles/year
£10,000	~16,000 miles/year

Company Car/Salary Sacrifice

Benefit in Kind Rates 2026/27

Vehicle	BiK Rate	Tax on £40k Car (Higher Rate)
Petrol (avg)	28%	£4,480/year
Diesel (avg)	32%	£5,120/year
Electric	3%	£480/year

EV company cars are 85-90% cheaper in benefit — massive saving for company car drivers.

Salary Sacrifice Example

£35,000 Electric Car	Petrol Equivalent
Gross monthly: £450	N/A (no scheme)
Net cost (40% taxpayer): £300	Buy outright: £600/month
Includes: Insurance, maintenance, tax

Depreciation

3-Year Depreciation Comparison

Vehicle Type	New Price	3-Year Value	Depreciation
Petrol (avg)	£30,000	£15,000	50%
Electric (avg)	£35,000	£19,250	45%

EVs are holding value better than petrol — and improving.

Future Cost Trends

Changes Coming

Factor	Direction	Impact on Case for EV
EV prices	Falling	Better
Electricity costs	Stable/rising	Slightly worse
Petrol prices	Rising	Better
Road tax on EVs	Coming 2025	Slightly worse
Charging infrastructure	Improving	Better
Battery costs	Falling	Better

Key Takeaways

1. EVs are cheaper to run — significantly lower fuel and maintenance
2. Home charging essential — 3-4p/mile vs 15-20p/mile
3. Higher mileage = bigger savings — fuel difference adds up
4. Company cars: EV wins hugely — 3% vs 28%+ BiK
5. Break-even typically 3-5 years — depending on mileage
6. Consider total cost — not just purchase price

For related content, see our salary sacrifice calculator, car finance explained, and car affordability calculator.