How much does it cost to charge a BMW i3 at home?
A full home charge of the BMW i3 120Ah (2018-2022) costs about £11.25 at the July 2026 Ofgem price cap (26.11p/kWh) — that is 5.8p per mile. The typical 20–80% top-up costs £6.75.
Prices based on the Ofgem price cap of 26.11 p/kWh, effective 1 July 2026.Source: Ofgem
Full charge
£11.25
at the Ofgem price cap
Running cost
5.8p /mile
at 5.1 mi/kWh incl. losses
20–80% on a 7 kW wallbox
3 hr 15 min
costing £6.75
Charging cost by tariff
| Tariff | Full charge | 20–80% | Per mile |
|---|---|---|---|
| Ofgem price cap26.11 p/kWh | £11.25 | £6.75 | 5.8p |
| Octopus Go off-peak (London example)8.63 p/kWh | £3.71 | £2.23 | 1.9p |
| Intelligent Octopus Go 12M Fixed off-peak (London example)8.00 p/kWh | £3.45 | £2.07 | 1.8p |
Costs include the ~12% energy lost during AC charging, so they reflect what your meter records. Off-peak rates assume all charging happens inside the cheap window — how much of your charging has to land in it decides whether an EV tariff pays. Rates vary by region. These are comparisons of published rates, not tariff recommendations.
How the i3 compares on running cost
Pence per mile at the Ofgem price cap. Shorter is cheaper.
Charging time by charger type
Most owners choose between a 7 kW wallbox and the socket they already have. A three-pin plug costs nothing to install but charges at about 2.3 kW, which is the difference between an overnight top-up and a two-day one on this car’s 37.9kWh pack. Charging away from home is a different calculation again — public rapid rates run several times higher.
| Charger | Speed for this car | 20–80% | Empty to full |
|---|---|---|---|
| Three-pin plug (2.3 kW) | 2.3 kW | 9 hr 53 min | 16 hr 29 min |
| 3.6 kW wallbox | 3.6 kW | 6 hr 19 min | 10 hr 32 min |
| 7 kW wallbox | 7 kW | 3 hr 15 min | 5 hr 25 min |
| 22 kW three-phase | 11 kWlimited by the car | 2 hr 4 min | 3 hr 27 min |
Times are simple energy-needed ÷ power estimates. Real sessions can run a little longer, because charging slows as the battery approaches full.
What affects these numbers for the BMW i3
This car charges at up to 11 kW on AC
The BMW i3's onboard charger accepts at most 11 kW from an AC connection. A 22 kW three-phase cannot charge it any faster than that, so there is no benefit in paying for a more powerful home charger than the car can use.
A three-pin plug is a backup, not a plan
From a standard three-pin socket (2.3 kW), an empty-to-full charge of the 37.9 kWh battery takes about 16 hr 29 min. Fine for overnight top-ups, but impractical as your only way to charge.
More efficient than most EVs
At 5.1 miles per kWh, the BMW i3 goes further on each unit of electricity than the typical EV, which is why its pence-per-mile figure is low for its size.
Real-world figures vary
The 192-mile range is the official WLTP lab figure. Cold weather and motorway speeds reduce real-world efficiency, which raises cost per mile and lowers range. Treat these numbers as good estimates, not promises.
The 50 kW DC figure is not for home charging
DC rapid charging at up to 50 kW only happens at public rapid chargers. All home charging is AC, so it is the 11 kW AC limit that matters for the times on this page.
BMW i3 120Ah— specifications used
- Usable battery
- 37.9 kWh
- WLTP range
- 192 miles
- Efficiency
- 5.1 mi/kWh
- Max AC charging
- 11 kW
- Max DC charging
- 50 kW
- Connector
- Type 2 / CCS
Data source: BMW UK press release + EV Database cross-check by Claude 2026-07-28: 42.2 kWh gross / 37.9 usable, 192 mi WLTP (BMW UK official; 310 km), 11 kW AC, 50 kW DC. Draft said 182 - corrected