Summary
UK electricity bills are calculated from two components: a unit rate (pence per kWh consumed) and a daily standing charge (a fixed daily fee regardless of usage). The Ofgem price cap sets maximum rates that suppliers can charge, updated quarterly. The calculator estimates your electricity cost based on appliance usage, helping you understand which devices cost the most to run and how to reduce your bill.
How it works
The bill formula
Annual electricity cost = (Unit rate x Annual kWh usage) + (Standing charge x 365)
For Q1 2026 (Ofgem price cap rates including 5% VAT):
- Unit rate: 27.69p/kWh
- Standing charge: 54.75p/day (£199.84/year)
Appliance running cost
Running cost = Power (kW) x Hours used x Unit rate
Common appliance costs per hour (at 27.69p/kWh):
| Appliance | Power (kW) | Cost per hour |
|---|---|---|
| LED light bulb | 0.01 | 0.3p |
| Laptop | 0.05 | 1.4p |
| TV (55”) | 0.08 | 2.2p |
| Washing machine | 0.5 (average) | 13.8p per cycle |
| Electric oven | 2.0 | 55.4p |
| Electric shower | 8.5 | £2.35 |
| Electric heater | 2.0 | 55.4p |
| EV charger (7kW) | 7.0 | £1.94 |
Average household usage
The Ofgem “typical” household uses approximately 2,700 kWh of electricity per year. This varies significantly:
- Small flat (1-2 people): 1,800-2,200 kWh
- Medium house (3-4 people): 2,700-3,500 kWh
- Large house (4+ people): 4,000-5,000 kWh
- Houses with electric heating: 7,000-12,000 kWh
Worked example
3-bedroom house, 3,200 kWh/year, Q1 2026 rates
- Unit cost: 3,200 x £0.2769 = £885.88
- Standing charge: 365 x £0.5475 = £199.84
- Annual bill: £885.88 + £199.84 = £1,085.72
- Monthly: £90.48
Inputs explained
- Annual consumption (kWh) — from your bill or estimated from appliance usage
- Unit rate — pence per kWh (defaults to Ofgem cap)
- Standing charge — daily fixed charge
- Appliance list — select appliances and usage hours for detailed breakdown
Outputs explained
- Annual/monthly electricity cost — total bill estimate
- Appliance breakdown — cost per appliance per day/month/year
- Comparison to average — how your usage compares to typical households
- Cost reduction tips — which changes would save the most
Assumptions & limitations
- Ofgem price cap rates are maximums for standard variable tariffs. Fixed-rate deals may be higher or lower.
- The standing charge is the same regardless of usage. Low-usage households pay a disproportionately high effective rate.
- Economy 7/10 tariffs have different day and night rates not modelled here.
- Electricity prices vary slightly by region across England, Scotland, and Wales.
- Prices change quarterly with the Ofgem cap review.