Free tools

Calculators that design the system with you

Every tool computes live as you type, explains its method, and turns your numbers into a brief you can hand any installer. Members save results across devices.

Off-Grid Solar Sizing Calculator

Daily kWh → array kW, panel count, battery bank, inverter size and a rough installed budget.

Load Calculator

Can I run my house off-grid? Tick your appliances → daily kWh, peak & surge watts, and a plain verdict.

Battery Bank Calculator

Autonomy, depth-of-discharge and voltage → usable kWh, Ah and bank cost.

Home Backup Power Calculator

The loads you keep on → generator kW, battery kWh and transfer-switch amps.

Water & Rain-Catchment Calculator

Roof, rainfall and household → annual harvest and the tank size that survives a dry spell.

Power Station Sizing Calculator

Devices and days → usable Wh, surge watts, recharge panel wattage and a matched size tier.

Mini Fridge Calculator

Can You Run a Mini Fridge Off-Grid?

Watts and duty cycle → real Wh/day, cloudy-day battery and the panel that keeps it cold.

Window AC Calculator

Can You Run a Window AC Off-Grid?

BTU and run hours → honest Wh/day, the start-up surge and the battery it really takes.

Well Pump Calculator

Can You Run a Well Pump Off-Grid?

Pump HP and water use → daily Wh, the surge that sizes the inverter, and the 240V question.

CPAP Calculator

Can You Run a CPAP Off-Grid?

Machine and humidifier settings → Wh/night, nights per battery, and the panel that makes it indefinite.

Sump Pump Calculator

Can You Run a Sump Pump Off-Grid?

Pump HP and storm cycling → Wh per storm day, surge watts and the battery that outlasts the outage.

No numbers required

Rather be asked than calculated?

The quizzes work the other way round: they ask about your life and hand you the answer — which energy source, which water source, which land, which region. Or take the whole assessment at once.

Become the Grid Browse the quizzes