The NumberTrove library
Energy
calculators.
Estimate a bill, size a system, or check the payback before you spend.
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Most people start with these
Electricity cost calculator
Turn appliance power, usage, and your electricity rate into a clear cost.
Open calculator ↗EV charging cost calculator
Estimate the cost of charging an electric vehicle at home.
Open calculator ↗Solar payback calculator
Estimate simple payback from system cost and annual energy savings.
Open calculator ↗All tools
33 energy calculators
Appliance running cost
Estimate what an appliance costs to run hourly, daily, monthly, and annually.
EnergyAir conditioner running cost
Estimate the energy cost of running an air conditioner.
EnergyAC cooling capacity converter
Convert air-conditioner cooling capacity between BTU per hour, refrigeration tons, and watts.
EnergySpace heater cost
Estimate what a space heater adds to your electricity bill.
EnergyEV charging time calculator
Estimate how long a charge will take from your battery size and charger power.
EnergyEV vs gas cost calculator
Compare the energy cost of driving electric with the equivalent gasoline cost.
EnergyShow 24 more energy tools ↓
Home EV charger sizing
Estimate the charging power and circuit size needed for your daily driving.
EnergySolar EV charging calculator
Estimate how much of your EV charging can be supplied by solar power.
EnergyEV battery degradation estimator
Estimate remaining battery capacity from age, mileage, and an annual degradation assumption.
EnergyEV battery percentage to range
Estimate remaining driving range from battery percentage and usable capacity.
EnergyEV real-world range calculator
Estimate practical EV range from battery size, driving mix, weather, and cabin use.
EnergyEV trip feasibility calculator
Check whether an EV trip is likely reachable with a chosen arrival reserve.
EnergyBattery ROI and payback calculator
Estimate battery payback, degradation, export value, financing cost, replacement impact, and cumulative cash flow.
EnergyEV vs petrol total cost calculator
Compare the ownership cost of an EV and a petrol vehicle over several years.
EnergyHome electrical load for EV charging
Estimate household load and the charging headroom left for a home EV charger.
EnergySolar system size calculator
Estimate the solar system capacity needed from daily electricity use, local solar resource, roof area, tilt, and orientation/shading assumptions.
EnergySolar generation calculator
Estimate daily and annual energy production from a solar system.
EnergySolar panel count calculator
Estimate how many panels are needed for a target solar system size.
EnergyHome battery size calculator
Estimate usable and nominal battery capacity for essential-load backup.
EnergyHome battery backup runtime calculator
Estimate backup hours from usable battery capacity and essential appliance load.
EnergyBangladesh electricity bill calculator
Estimate a monthly DESCO/BERC residential bill from kWh used: step tariff, demand charge, meter rent, VAT, and the prepaid rebate.
EnergyIndian state electricity bill calculator
Estimate a domestic electricity bill with selectable slab tariffs for Maharashtra, Delhi, Karnataka, or West Bengal.
EnergyIPS / UPS backup battery calculator
Size the battery bank and inverter for load-shedding backup: Ah needed, batteries to buy, and inverter VA for your appliances and hours.
EnergyGenerator size calculator
Size a standby or portable generator in kW and kVA from running load, motor starting surge, and a safety margin, with fuel use and running cost.
EnergyEssential loads calculator
Estimate the energy needed to keep selected appliances running during an outage.
EnergyInverter size calculator
Estimate normal load, peak load, and a practical inverter size from appliance demand.
EnergyShould I buy an EV?
Assess whether an electric vehicle fits your driving, parking, charging, and road-trip routine.
EnergyShould I buy a home battery?
Assess whether backup needs, solar, outages, and electricity pricing support adding a battery.
EnergyEV road-trip calculator
Estimate charging energy, state-of-charge stops, time, and cost for a planned EV trip.
EnergyIntegrated home energy planner
Combine home demand, solar generation, battery backup, EV driving, and grid import/export in one transparent daily or hourly scenario.
EnergyHow to choose the right energy calculator
Energy decisions become clearer when usage is translated into money, time, or capacity. NumberTrove’s energy calculators cover electricity cost, appliance running cost, air conditioners, space heaters, EV charging cost and time, EV-versus-gas comparisons, home charger sizing, solar charging, battery degradation, and solar payback. Use them to estimate a bill, compare equipment, plan a charging routine, or sanity-check a proposed solar or EV investment.
Choose an electricity or appliance calculator when you know watts, hours, and a price per kilowatt-hour. Use the EV tools when battery size, charging power, efficiency, or driving distance is the key input. Charger sizing focuses on electrical power, while solar and payback tools combine energy production with cost assumptions. Rates, tariffs, weather, losses, and driving habits vary, so treat the result as a planning estimate and update it with your own bill or equipment data. Comparing two scenarios with the same rate and time period often reveals the practical tradeoff more clearly than a single headline number.
Use your local electricity rate where possible and separate the energy used from the price charged. Real results vary with tariffs, losses, weather, driving habits, and equipment efficiency.
Every tool is free, browser-based, and shows its formula, assumptions, and related calculators. Start with the closest match, then adjust the inputs to fit your situation.