generator tool
Generator Runtime Calculator
Estimate runtime from fuel on hand and a user-entered consumption rate.
Fuel consumption varies by generator model, fuel type, load, and operating conditions. Enter a model-specific rate; no universal rate is assumed.
Estimated runtime
10 hours
Runtime = fuel available ÷ fuel consumption rate. A zero rate returns zero until a valid rate is entered.
Generator runtime guide
Estimate runtime from fuel and consumption rate
The current calculator uses two inputs: fuel available in gallons and fuel consumption rate in gallons per hour. It does not infer a universal rate from generator size or load.
Formula
runtime hours = fuel gallons ÷ fuel gallons per hour
A zero or invalid rate returns zero in the current utility so the page never reports infinite runtime.
Worked examples
Example 1: 5 gallons ÷ 0.5 gallons per hour = 10 hours.
Example 2: 12 gallons ÷ 0.75 gallons per hour = 16 hours.
What changes actual runtime?
Load percentage, generator efficiency, engine condition, fuel type, temperature, altitude, maintenance, and the manufacturer's fuel-consumption data can all affect real runtime. Use a model-specific rate rather than treating these examples as universal performance claims.
Illustrative reference table
| Fuel available | Rate | Estimated runtime |
|---|---|---|
| 5 gal | 0.5 gal/hr | 10.0 hours |
| 12 gal | 0.75 gal/hr | 16.0 hours |
| 20 gal | 1 gal/hr | 20.0 hours |
Frequently asked questions
What formula does the runtime calculator use?
Runtime equals fuel available divided by fuel consumption rate.
Why does load affect actual runtime?
A generator engine normally consumes fuel differently at different load percentages. This calculator asks for a consumption rate, so use a rate that matches the generator model and operating condition when possible.
What happens if the rate is zero?
The current implementation returns zero rather than displaying an infinite runtime.
Is the runtime guaranteed?
No. Fuel type, load, engine condition, temperature, environment, and manufacturer data can change actual runtime.
Important assumptions
This is a planning estimate, not a guarantee of performance. Real equipment varies with temperature, age, power quality, duty cycle, wiring, and manufacturer specifications.