Electricity Cost Calculator
Calculate the running costs of your electrical appliances and devices with our free, easy-to-use calculator
How to Calculate Electricity Costs
Calculating electricity costs is straightforward once you know the basic formula. The cost depends on three main factors: the power consumption of your appliance (measured in watts or kilowatts), how long you use it, and your electricity tariff rate.
The Basic Formula
Energy Cost = Power (kW) × Usage Time (hours) × Tariff Rate (p/kWh) ÷ 100
For example, if you have a 2000W (2kW) electric heater running for 3 hours at a tariff rate of 25.73p per kWh:
Cost = 2 × 3 × 25.73 ÷ 100 = £1.54
Current UK Electricity Rates (September 2025)
The current average electricity rate in the UK is approximately 25.73p per kWh under the energy price cap, with a daily standing charge of around 51.37p per day. These rates can vary slightly by region and payment method.
Common Appliance Power Consumption
| Appliance | Typical Power (Watts) | Cost per Hour* |
|---|---|---|
| LED Light Bulb (60W equivalent) | 9W | 0.2p |
| Laptop Computer | 50W | 1.3p |
| Desktop Computer | 200W | 5.1p |
| Flat Screen TV (42″) | 150W | 3.9p |
| Microwave Oven | 1000W | 25.7p |
| Electric Kettle | 2200W | 56.6p |
| Washing Machine | 500W | 12.9p |
| Tumble Dryer | 2500W | 64.3p |
| Electric Heater | 2000W | 51.5p |
| Air Conditioning Unit | 1500W | 38.6p |
*Based on 25.73p per kWh tariff rate
Energy Saving Tips
Switch to LED Bulbs
LED bulbs use up to 85% less energy than traditional incandescent bulbs and last much longer, providing significant savings over time.
Unplug Standby Devices
Many devices consume power even when switched off. Unplugging chargers, TVs, and other electronics when not in use can save £30-40 annually.
Use Energy-Efficient Appliances
Look for appliances with high energy efficiency ratings (A+++ is the best). They may cost more upfront but save money in the long term.
Optimise Heating
Lowering your thermostat by just 1°C can reduce heating bills by up to 10%. Consider smart thermostats for better control.
Wash Clothes at Lower Temperatures
Washing at 30°C instead of 40°C can save up to 40% of the energy used per wash cycle whilst still achieving effective cleaning.
Improve Insulation
Better insulation reduces the need for heating and cooling, potentially saving hundreds of pounds annually on energy bills.
Frequently Asked Questions
Our calculator provides highly accurate estimates based on the information you provide. The accuracy depends on using the correct power consumption figures for your appliances and your actual electricity tariff rate. Results may vary slightly due to factors like appliance efficiency variations and regional tariff differences.
Your electricity tariff rate is shown on your energy bill, usually expressed as pence per kilowatt-hour (p/kWh). It’s typically found in the charges breakdown section. If you can’t find it, contact your energy supplier or check their website. The current UK average is around 25.73p/kWh.
Watts (W) and kilowatts (kW) both measure power consumption. One kilowatt equals 1,000 watts. For example, a 1,500W heater is the same as a 1.5kW heater. Most small appliances are measured in watts, whilst larger appliances like electric heaters are often measured in kilowatts.
Several strategies can help reduce electricity bills: switch to energy-efficient LED bulbs, unplug devices when not in use, use appliances during off-peak hours if you have a time-of-use tariff, improve home insulation, and consider switching to a cheaper energy supplier. Small changes can add up to significant savings.
A standing charge is a fixed daily fee that covers the cost of connecting your home to the energy network, maintaining the infrastructure, and meter readings. It’s charged regardless of how much energy you use. The current average standing charge for electricity is around 51.37p per day in the UK.
Electricity costs vary by region due to differences in distribution network costs, local infrastructure requirements, and the distance electricity must travel. Rural areas often have higher costs due to longer distribution networks, whilst urban areas may benefit from more efficient distribution systems.