1. Add what you know
Use figures from your bills, or begin with clearly labelled GB assumptions.
UK home energy, clearly explained.
See what energy choices mean for your whole home.
Bills, solar, batteries, EVs, tariffs and heating all affect one another. Home by Numbers connects them using your figures, so you can see what could cost, save and genuinely matter.
- Free calculators
- No account needed
- No phone number
- No sales calls from us
My EnergySolarBatteryEVHeatingTariffs
Your home isn't a collection of separate calculators.
Your electricity price changes the value of solar, batteries and home EV charging. Heating can transform your electricity demand, and all of those choices can change which tariff works best.
My EnergySolarBatteryEVHeatingTariffs
Change one number. See what it changes elsewhere.
Each calculator works on its own, while shared figures already connect your home energy, solar, battery, EV, heating and tariff comparisons. We'll continue making those connections deeper over time.
Start simple. Go deeper when you want.
2. Choose what you're considering
Explore your energy costs, solar, a battery, changing car, tariffs or heating.
3. Play with the possibilities
Move the sliders and see the financial effect immediately. Your original figures remain unchanged.
You never need to complete a long questionnaire before seeing something useful.
What would you like to understand?
Start with one question. Everything you've already entered will follow you into the next calculator.
Available now
My Energy
Understand where your money goes and what every 1p change means to your household.
Understand my billsAvailable now
Solar
Estimate generation from your location and roof, then see bill savings, export income and payback.
Explore solarAvailable now
Battery
See what a battery could really save after charging losses and export income are accounted for.
Explore batteriesAvailable now
EV and plug-in hybrid
Compare petrol or diesel with your real charging mix, including cheap-rate and surplus-solar charging.
Compare carsAvailable now
Heating
Compare how changing the way you heat your home could alter both your fuel use and electricity demand.
Compare heatingAvailable now
Tariffs
Understand how different unit rates, standing charges and charging periods could affect your whole home.
Compare tariffsAnswers that explain themselves.
Examples of the kind of insight each calculator gives you — not results for your home.
See what every 1p change is worth over a year
Estimate solar generation using your location and roof
Value stored solar after accounting for export income
Compare an EV using where you would actually charge it
See the performance a heat pump would need to beat your present heating cost
See how a tariff change could affect your wider home
Your results are calculated from your figures, with the assumptions and limitations shown beside them.
Numbers first. Commercial links second.
Home by Numbers is designed to give you the calculation before asking you to take any action. We don't change a result to favour a product or provider. If you choose to use a clearly marked partner link to switch or request a quote, we may earn a commission. That helps keep the core calculators free.
- No result hidden behind contact details
- Assumptions you can inspect and change
- Honest answers when an option may not be worthwhile
Understand your home one number at a time.
Begin with your current electricity and gas figures. You can explore everything else from there.
No account required. Your figures are stored on this device.