BMW i3 42 kWh home charging cost — Daily top-up (20%→80%)
Charging a BMW i3 42 kWh (42 kWh battery) on the Daily top-up (20%→80%) pattern uses 25.2 kWh per session and costs £6.58 at the current Ofgem cap rate of 26.11p/kWh (1 July to 30 September 2026).
Source: Ofgem (OGL v3.0) + SMMT / manufacturer press packs — UK EV battery capacity and WLTP range data 2024–2025. Published 2026-06-20.
BMW i3 42 kWh — Daily top-up (20%→80%): 25.2 kWh per session × 26.11p/kWh = £6.58/charge. 7 sessions/week = £46.06/week ≈ £199.58/month ≈ £2395.02/year. Cost per mile (WLTP): ~7.2p. Source: Ofgem price cap (OGL v3.0), SMMT / manufacturer press packs — UK EV battery capacity and WLTP range data 2024–2025.
- Per charge session
- £6.58
- Per week (7 sessions)
- £46.06
- Per month (avg)
- £199.58
- Per year
- £2395.02
BMW i3 42 kWh specification
- Battery capacity
- 42 kWh
- WLTP range
- 153 miles
- Full charge cost
- £10.97
- Cost per mile (WLTP)
- ~7.2p
- Charge pattern
- 60% of battery
- kWh per session
- 25.2 kWh
BMW UK — i3 spec sheet 2022 (42.2 kWh usable, 153-mile WLTP; production ended 2022)
How the cost is worked out
- Battery capacity: BMW i3 42 kWh has a 42 kWh usable battery (SMMT/manufacturer data).
- Charge amount: 60% of battery = 42 × 0.6 = 25.2 kWh per session.
- Cost per session: 25.2 kWh × 26.11p/kWh = £6.58.
- Weekly: £6.58 × 7 sessions = £46.06.
- Annual: £46.06/week × 52 weeks = £2395.02.
Note: assumes 100% charging efficiency. Real chargers typically have ~10% loss, so actual electricity drawn from the grid is slightly higher. Rapid public charging costs are set by commercial operators and are not subject to Ofgem cap.
Frequently asked questions
How much electricity does a BMW i3 42 kWh use to charge?
The BMW i3 42 kWh has a 42 kWh usable battery. The Daily top-up (20%→80%) pattern charges 60% of the battery, using 25.2 kWh per session. A full 0%→100% charge uses 42 kWh and costs £10.97 at the current Ofgem rate.
What is the cost per mile for a BMW i3 42 kWh when charged at home?
Based on the WLTP range of 153 miles from a full 42 kWh battery, the electricity cost per mile at home is approximately 7.2p/mile at the Ofgem cap rate of 26.11p/kWh. Real-world range will vary by driving style, weather, and speed.
What does it cost to run a BMW i3 42 kWh per year on electricity?
On the Daily top-up (20%→80%) pattern (7 sessions/week), the estimated annual electricity cost is £2395.02 at 26.11p/kWh (1 July to 30 September 2026). The actual cost depends on your real charging pattern and whether the Ofgem cap changes before the year is out.
Find a home EV charger installer
Getting a 7.4 kW home EV charger installed typically costs £800–£1,200 and can halve your per-mile electricity cost vs slow 3-pin charging. GeraHome connects you with OZEV-approved charger installers in your area.
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Battery capacity (42 kWh) from BMW UK — i3 spec sheet 2022 (42.2 kWh usable, 153-mile WLTP; production ended 2022). Unit rate 26.11p/kWh from Ofgem — Energy price cap unit rates and standing charges (1 July to 30 September 2026). OGL v3.0.