Start with the number you need
Use the full bill estimator for household costs, then use the specialist calculators to find where savings may come from.
Energy Bill Estimator
Estimate annual, monthly and daily gas and electricity costs from usage, unit rates and standing charges.
Estimate your bill → AppliancesElectricity Cost Calculator
Calculate how much an appliance costs to run from watts, hours, days and pence per kWh.
Calculate appliance cost → Quick savingLED Savings Calculator
Compare old bulbs with LEDs and estimate annual saving, kWh saved and payback time.
Calculate LED savings → SolarSolar Panel Payback Calculator
Estimate payback from installation cost, generation, self-use, import rates and export tariff income.
Estimate solar payback → HeatingBoiler Replacement Cost Calculator
Model boiler or heat pump replacement cost, grant-adjusted cost, savings and payback.
Compare heating costs → InsulationLoft Insulation Savings Calculator
Estimate insulation payback, 5-year saving and 10-year saving from installation cost and annual saving.
Calculate insulation saving →Energy rates used as defaults
The calculators let you enter your own tariff, but default electricity and gas examples use the current Ofgem price-cap period.
Ofgem’s price cap for 1 July to 30 September 2026 is £1,862 per year for a typical Direct Debit dual-fuel household. The cap limits unit rates and standing charges, not the total amount a household can pay.
What should you check first?
Home energy savings are easier to understand when you move from whole-bill cost to specific causes and upgrades.
Estimate the whole bill
Start with the Energy Bill Estimator so you know the size of the problem and the split between usage and standing charges.
Find expensive usage
Use the Electricity Cost Calculator to understand appliances, heaters, dryers, lighting and other high-use items.
Check quick savings
LED lighting and behaviour changes can be lower-cost actions before major upgrades.
Compare bigger upgrades
Solar, boiler replacement, heat pumps and insulation can all help, but payback depends on cost, tariffs and your home.
Compare savings before spending
Use the calculators to avoid guessing which upgrade should come first.
Best for electricity offset
Payback depends on install cost, generation, self-use and SEG export tariff income.
Best for heat loss
Loft insulation can reduce heat loss and may support future heating upgrades.
Best for old systems
Boiler or heat pump payback depends on quote, grant, running cost and property efficiency.
Best for rate changes
A fixed energy tariff can change risk and predictability compared with a variable tariff.
Read before you decide
These guides turn the calculator results into practical next steps.
How to Lower Your Energy Bill Without Guesswork
A practical decision path from bill estimate to appliance usage, tariff checks and home upgrades.
Supporting guideWhich Appliances Use the Most Electricity at Home?
Understand heaters, dryers, cooking, lighting, standby costs and usage habits.
GuideFixed Energy Tariff vs Variable Tariff
Compare price certainty, price-cap exposure, exit fees and household risk.
GuideAre Solar Panels Worth It in the UK?
Use install cost, generation, self-use and export tariffs to judge solar value.
GuideBoiler, Heat Pump or Insulation: What Should You Upgrade First?
Compare heating upgrades, insulation and low-carbon options before spending.
Understand the terms on your bill
These glossary pages support the calculators and explain the language behind energy bills and upgrades.
Built around editable assumptions
Energy figures change, so every calculator lets you replace defaults with your own bill, quote or tariff values.
The Home & Energy calculators are designed for quick planning. They do not replace supplier bills, installer quotes, EPC assessments, grant eligibility checks or professional advice.
Compare energy-saving options
Calculatorz may earn a commission if you choose a partner through our links. Estimates are for guidance only.
Home & Energy FAQs
Which Home & Energy calculator should I use first?
Start with the Energy Bill Estimator if you want a whole-household view. Use the other calculators for appliances, lighting, solar, heating and insulation decisions.
Do the calculators use my actual tariff?
They include editable default values. For best results, replace defaults with your own unit rates, standing charges, usage figures, quotes and export tariff.
Can the Ofgem price cap limit my total bill?
No. The cap limits unit rates and standing charges on default tariffs. Your total bill still depends on actual usage.
Are solar, boiler and insulation results guaranteed?
No. They are estimates only. Actual results depend on property, behaviour, installation quality, tariffs, weather, eligibility and future energy prices.