Energy & Household Bill Calculators UK
Free energy and household bill calculators for the UK: running costs per kWh, bills under the price cap, solar panels and water use.
- Calculators12
- Rules and figuresUK, November 2026
- CostFree, no sign-up
Energy & bills calculators
Water meter calculatorWould a water meter save you money? Compare with your bill.Off-grid solarSize panels, battery and inverter for an off-grid system.kWh cost calculatorRunning cost of any appliance from watts, hours and unit price.Water usage calculatorLitres a day your home uses, by activity, and the metered cost.Energy bill calculatorYearly and monthly gas and electricity bill from your usage.Heat pump running costHeat pump kWh and running cost vs your gas boiler.Solar panel costSolar PV cost, generation, savings, export income and payback.Radiator BTURoom heat loss in BTU and watts, and the radiator size you need.Heat pump costNet heat pump cost after the £7,500 grant, and running costs.Light bulb running costCompare the running cost of LED, halogen and old bulbs.BTU calculatorRoom heating BTU, air-con size and BTU to kW conversion.Carbon footprintHousehold CO2e from energy, driving and flights (2026 factors).
What each calculator does
| Calculator | What it works out |
|---|---|
| Water meter calculator | Would a water meter save you money? Compare with your bill. |
| Off-grid solar | Size panels, battery and inverter for an off-grid system. |
| kWh cost calculator | Running cost of any appliance from watts, hours and unit price. |
| Water usage calculator | Litres a day your home uses, by activity, and the metered cost. |
| Energy bill calculator | Yearly and monthly gas and electricity bill from your usage. |
| Heat pump running cost | Heat pump kWh and running cost vs your gas boiler. |
| Solar panel cost | Solar PV cost, generation, savings, export income and payback. |
| Radiator BTU | Room heat loss in BTU and watts, and the radiator size you need. |
| Heat pump cost | Net heat pump cost after the £7,500 grant, and running costs. |
| Light bulb running cost | Compare the running cost of LED, halogen and old bulbs. |
| BTU calculator | Room heating BTU, air-con size and BTU to kW conversion. |
| Carbon footprint | Household CO2e from energy, driving and flights (2026 factors). |
Using these calculators
Energy prices change every quarter with the Ofgem price cap. Enter the unit rates on your own bill for the most accurate result.