Calculators Backup power planning
How long can my generator run on the fuel I have?
Use your generator’s fuel-use figures to estimate runtime and target fuel.
About 3 minutes You’ll need: generator fuel-use figures, fuel, and selected loads
Generator runtime calculator for household backup power planning
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Carbon monoxide: generators stay outdoors
Keep it at least 20 feet from doors, windows, and vents—never in a home, garage, basement, or shed. Use working carbon-monoxide alarms and follow the manual. CDC safety guidance.
Plan runtime and target fuel without guessing at consumption
Use the exact figures from your generator manual, keep the planned electrical load within the documented fuel-use range, and preserve a reserve without treating the result as a fuel-storage recommendation.
- Copy the model's fuel-use figures and units from its manual, then enter the fuel you can safely store and rotate.
- Add essential running loads, check startup requirements separately, and keep the plan at or below 75 percent of rated output.
- Choose a target runtime, compare the required planning fuel with what is safely and lawfully available, and test the equipment outdoors before an emergency.
Common questions
Why do I need the manufacturer fuel-use table?
Fuel consumption varies by model, fuel, load, maintenance, temperature, and altitude. The model-specific manual is more dependable than a generic gallons-per-hour assumption.
Can I enter propane in pounds instead of gallons?
Use one consistent liquid-volume unit for both available fuel and the manual's consumption rate. Do not mix pounds, gallons, liters, or gaseous-volume figures without a verified conversion for the exact fuel conditions.
How much generator fuel do I need for an outage?
Use the exact generator's manufacturer fuel-use figures at the planned load. The estimator multiplies the interpolated burn rate by your target hours, then divides by the fraction of fuel left after your chosen reserve. That keeps the same share of total fuel untouched in both views. The planning total is not permission to store a particular quantity at home; follow the fuel-container instructions and current local fire rules.
What does a 20% fuel reserve mean?
It means keeping one fifth of the total fuel unused, rather than adding one fifth to the fuel you expect to burn. For illustration only, a burn rate of 0.25 gallons per hour uses 6 gallons in 24 hours. With a 20% reserve, the planning total is 6 ÷ 0.8 = 7.5 gallons: 6 to use and 1.5 held back. This is arithmetic, not a generator specification or a storage recommendation; enter your exact manual's figures.
Where is it safe to run a portable generator?
Keep it outdoors at least 20 feet from doors, windows, and vents, follow the exact manual, never use it in a home or garage, and use working carbon-monoxide alarms.