Calculators for your energy bills
Free, no-signup home-energy math — what each appliance costs to run, whether solar pays off, what size generator you need, how much LEDs save, and the cost of standby ‘vampire’ power. Every calculator shows its formula.
Appliance Running Cost Calculator
What it costs to run any appliance — per day, month, and year — from its wattage and your electricity rate.
Estimate running costSolar Panel Payback Calculator
How many years until home solar pays for itself — production, the 30% federal tax credit, and 25-year savings.
Estimate paybackGenerator Sizing Calculator
What size backup generator you need — running watts plus the startup surge of your biggest motor.
Size a generatorLED Savings Calculator
What you save switching bulbs to LED — per year, over 10 years, plus CO2 avoided.
See LED savingsPhantom Load Calculator
The yearly cost of ‘vampire’ standby power from devices left plugged in 24/7.
Find vampire powerEV vs Gas Cost Calculator
Compare cost per mile and yearly fuel cost for an EV versus a gas car.
Compare EV vs gasGuides
Plain-English help: lowering your electric bill, how solar payback works, and sizing a home generator.