Electricity Usage and Measurement
Generator Fuel Runtime Calculator
Use Generator Fuel Runtime when generator runtime is the quantity you need. Enter usable fuel and fuel consumption, then compare the answer with the equipment or operating limits that apply to your case.
Set up the Generator Fuel Runtime case
Check the source and units before calculating.
Before entering values
Use tariff periods, demand intervals, meter ratios, and operating hours from the same billing case. Write down whether each entry is measured, rated, assumed, or calculated.
At least one field has a positive lower bound because it appears in a denominator. Use the displayed unit for every field and document conversions separately. For the companion state of charge calculation, open Battery State of Charge Calculator.
- Usable fuel
- Default example: 120 L. Enter usable fuel in L.
- Fuel consumption
- Default example: 15 L/h. Enter fuel consumption in L/h.
Generator runtime: calculation method
The arithmetic is based on runtime = fuel ÷ consumption. The participating entries are Usable fuel and Fuel consumption.
The defaults produce 8.00 h. Replace them with measurements from one operating state.
Calculate generator runtime from usable fuel and fuel consumption. Generator Fuel Consumption Calculator covers the related fuel use step.
Using the answer downstream
Record usable fuel and fuel consumption with generator runtime. Include the operating state and data source.
Carry generator runtime with all available digits during downstream arithmetic. Round at the final reporting step.
Applying the result
The primary answer, Generator runtime, describes only the entered scenario. Compare it with the relevant tariff and measured load profile.
Label alternate cases rather than overwriting the baseline. Another relevant worksheet is Electrical Power Cost Calculator.
Before accepting the number
Unit-prefix mistakes often dominate the arithmetic error.
Check the input source before adding a safety or correction factor.
What the formula leaves out
Reserve fuel and changing load reduce runtime.
The equation does not include meter accuracy, sampling interval, waveform bandwidth, and conversion loss. Document which effects were checked elsewhere in the analysis.
Record meter scaling, time period, load profile, and applicable tariff. If you also need generator loading, continue with Generator Load Percentage Calculator.
A final reasonableness check
Begin by confirming fuel consumption at the operating point represented by the other entries. Record whether it came from a meter, nameplate, data sheet, or design assumption.
The displayed generator runtime should be checked against base, peak, and changed-operation scenarios. Investigate an unexpected magnitude before changing the model or adding margin.
If uncertainty remains, calculate labeled low and high cases. Include fixed charges, demand ratchets, seasonal rates, uncertainty, and future load change when those effects can change the decision.
Before relying on the answer
What is not captured by this equation?
Reserve fuel and changing load reduce runtime. Also consider fixed charges, demand ratchets, seasonal rates, uncertainty, and future load change.