What an EV charging session actually costs
Read energy, time, session, and other fees as one bill—not four unrelated numbers.
Start with every price component
A charging tariff can combine an energy rate, a per-minute rate, a fixed session charge, and other applicable charges. Looking at only the energy rate hides any amount that does not scale with delivered kWh.
EU Alternative Fuels Infrastructure Regulation uses that same component order for ad hoc pricing at newly deployed public charging points below 50 kW: price per kWh, price per minute, price per session, then any other component.
- Energy rate: electricity delivered, usually shown in £/kWh.
- Time rate: minutes connected, charging, or occupying the bay—check exact trigger.
- Session fee: fixed amount charged once each time charging starts.
- Other charges: provider-specific additions such as an occupancy or roaming-related charge.
Build the session total
Convert each component into pounds for the session, then add them. Keep provider wording beside each value so a time fee is not mistaken for an energy fee.
Formula
Session total = (energy added × energy rate) + session fee + time and idle fees
35 kWh × £0.52 + £1.50 + £2.00 = £21.70
If any tariff line has no trigger, unit, or cap, ask provider before treating estimate as complete.
Turn total into an effective energy rate
Effective £/kWh makes tariffs comparable because it spreads fixed and time-based fees across energy actually received. Small top-ups often carry a higher effective rate because fixed fees are divided by fewer kWh.
Formula
Effective rate = session total ÷ energy added
£21.70 ÷ 35 kWh = £0.62/kWh
Translate charging cost into driving cost
Vehicle consumption connects charging price to distance. Use a realistic recent consumption figure, not a best-case brochure value, when deciding what the tariff means for routine driving.
Formula
Cost per 100 miles = effective £/kWh × vehicle kWh/100 miles
£0.62 × 29.8 kWh/100 miles = £18.48/100 miles
Keep comparison tied to one scenario
A tariff is not universally cheap or expensive. Result changes with energy added, time connected, idle exposure, and payment route. Compare providers with same session assumptions, then test a second scenario that reflects a smaller top-up or longer stay.
Official sources
- EUR-Lex: Regulation (EU) 2023/1804, Article 5
- European Commission: Alternative fuels infrastructure data transparency
Provider channel remains source for current station-specific price and terms.