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Generator Calculators

Free interactive calculators to help you size, run, and save with your generator. 51 expert-built tools for homeowners, campers, and pros.

  • 51 Calculators
  • 8 Categories
  • 100% Free to use

Power Sizing 9

Generator Size Calculator Find the right generator wattage for your appliances. Add up running and starting watts with a safety margin. AC Generator Size Calculator Can your generator start and run your air conditioner? Check starting vs running watts. Inverter Generator Size Calculator Find the right inverter generator — or a parallel pair — for clean, quiet power. Appliance Wattage Calculator Look up running and starting watts for 70+ common appliances. RV Generator Size Calculator Size a generator for roof ACs and RV loads by electrical service type. Job Site Generator Calculator Size a generator for construction tools with duty-cycle awareness. Food Truck Generator Calculator Size a quiet generator for continuous commercial food truck loads. Well Pump Generator Calculator Minimum generator size to start and run your well pump. EV Charging Generator Calculator Can a generator charge your EV? See charge time and fuel burned.

Runtime & Fuel 8

Generator Runtime Calculator Estimate how long your generator will run on a full tank at a given load. Fuel Consumption Calculator Calculate gallons per hour and total fuel needed for your generator and load. Propane Tank Runtime Calculator How long will a 20 lb propane tank run your dual-fuel generator? Dual Fuel Cost Comparison Calculator Gasoline vs propane: which is cheaper per hour for your generator? Fuel Storage Calculator How much fuel to store for a planned outage, with reserve and stabilizer dose. Load vs Runtime Calculator Slide your load up and down and watch runtime change. Natural Gas Consumption Calculator Natural gas usage for tri-fuel and standby generators in CCF and dollars. Diesel Generator Fuel Calculator Diesel burn rate, runtime, and hourly cost for diesel generators.

Cost & Savings 7

Generator Fuel Cost Calculator See exactly what it costs per hour, day, and month to run your generator. Portable vs Standby Cost Calculator 10-year true cost: portable + transfer switch vs automatic standby. Solar vs Gas Generator Cost Calculator 10-year cost showdown: solar generator vs gas generator + fuel. Generator Payback Calculator How fast a generator pays for itself in avoided outage losses. EV Charging Cost Calculator Generator vs grid: what a generator-charged kWh really costs. Outage Fuel Cost Estimator Total fuel bill for a multi-day outage — plan before the storm. Standby Installation Cost Estimator Itemized installed-cost estimate for a whole-house standby generator.

Solar & Battery 9

Solar Generator Size Calculator Size the right solar generator and battery capacity for your power needs. Solar Panel Calculator How many solar panels do you need to charge your solar generator or power station? Power Station Runtime Calculator How long will a portable power station run your devices? Enter battery capacity and load. Solar Charging Time Calculator How long solar panels take to recharge your power station. Battery Capacity Converter Convert between Wh, Ah, and mAh at any voltage. Off-Grid Solar System Calculator Size a full off-grid setup: battery bank, solar array, and inverter. Battery Lifespan Calculator How long LiFePO4 vs NMC batteries last by your actual usage. Power Station Expansion Calculator Total capacity, runtime, weight, and cost per Wh when adding extra batteries. Solar Recharge Savings Calculator Savings from solar-charging your power station instead of wall-charging.

Electrical & Wiring 7

Extension Cord Gauge Calculator Pick the safe wire gauge for your extension cord based on amps and distance. Transfer Switch Size Calculator What size manual transfer switch do you need for your generator and home circuits? Voltage Drop Calculator Voltage drop, percent loss, and NEC verdict for any wire run. Breaker Size Calculator Correct breaker size for a generator-fed circuit, per NEC rules. Generator Wire Gauge Calculator Wire gauge for the generator inlet-box run with ampacity and drop checks. Amps to Watts Converter Convert between amps, watts, and volts in any direction. Generator Parallel Kit Calculator Combine two inverter generators: total output and the right kit type.

Home Backup 4

Whole House Generator Size Calculator Estimate the kW standby generator your whole home needs based on square footage and appliances. Power Outage Survival Calculator How long your backup lasts across priority tiers — and what to shed. Sump Pump Backup Calculator Battery or generator size to keep your sump pump running through a storm. Medical Device Backup Calculator Backup power for CPAP, oxygen concentrators, and medical devices.

Maintenance 4

Oil Change Interval Calculator When your next generator oil change is due — in hours and on the calendar. Maintenance Schedule Calculator A personalized maintenance timeline from your usage pattern. Fuel Stabilizer Calculator Exact stabilizer dose for stored fuel: STA-BIL, Sea Foam, or PRI-G. Generator Safety Distance Checker Is your generator placement safe? Checked against the 20-foot CO rule.

Outdoor & RV 3

Camping Power Calculator Size a power station + solar panel for your whole camping trip. RV AC Soft Start Calculator Will a soft starter let your small generator start the RV air conditioner? Tailgating Power Calculator Power your tailgate: TV, speakers, cookers — generator or power station?