Know what your energy will cost before you commit
Calculators for heat pumps, electric cars, solar panels and everyday appliances, built around European prices, units and billing. Every formula is on the page and every default can be changed.
Is a heat pump cheaper than gas for you?
Three numbers give you the break-even efficiency. Prices per kWh in your own currency.
Assumes a gas boiler at 90 percent efficiency. Open the full calculator for installation cost, grants and payback.
Calculators
- Appliance running cost calculator
Turn a wattage label into a cost per hour, day, month and year at your own electricity price.
- Electricity bill calculator
Turn your kWh, unit rate and standing charge into a monthly and yearly bill and your true price per kWh.
- EV charging cost calculator
Price any charge from the socket, see the range it adds, the cost per 100 km and the time it takes.
- EV vs petrol cost calculator
Compare a year of electric driving with petrol or diesel and see when the extra purchase price pays back.
- Gas m3 to kWh calculator
Convert cubic metres or hundreds of cubic feet from your gas meter into kWh, using the factors on your bill.
- Heat pump vs gas boiler calculator
Compare yearly running costs, find the break-even efficiency and see how long a heat pump takes to pay back.
- LED savings calculator
See what swapping halogen or incandescent bulbs for LEDs saves each year and how fast the new bulbs pay back.
- Solar panel payback calculator
Estimate how many years a rooftop system takes to pay back and what it earns over 25 years.
Recent guides
- Heat pump vs gas boiler running costs explained
Why the price ratio between electricity and gas, plus the efficiency of your install, decides whether a heat pump is cheaper to run.
- kW vs kWh: the difference explained
Power and energy explained with kettles, wallboxes, solar panels and batteries.
- Schuko socket EV charging vs a wallbox: speed compared
Charge times from a household socket and from 3.7, 7.4, 11 and 22 kW wallboxes, and what limits each.
- Time-of-use tariffs explained with a break-even test
How day and night rates work, the share of use you must shift to come out ahead, and what it saves with an EV.
- Boiler efficiency explained: what it means for your gas bill
What a boiler efficiency percentage means, how real-life efficiency differs from the label and what an upgrade saves.
How this site stays accurate
Each calculator uses a published formula, and the worked examples in the guides are produced by the same code that powers the tool, so a table can never quietly disagree with a result. Prices and grants are inputs you control, because they change faster than any website can keep up. The method page lists every formula and assumption, and the editorial policy explains how corrections are handled.