5 kW load, gasoline, 8 hours
- Fuel/hour ≈ 5 × 0.1 = 0.5 gal
- Total ≈ 0.5 × 8 = 4 gallons
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Generator Fuel Consumption Calculator
Estimate fuel use per hour and total fuel for a generator based on load and fuel type.
Results
- Estimated fuel use per hour
- 0.50
- Total fuel needed
- 4.00
How to use this calculator
- Enter your expected load in kW (or kVA ≈ kW for resistive loads).
- Select fuel type and planned runtime hours.
- Review estimated gallons per hour and total fuel needed.
Inputs explained
- Load
- Average kW load you expect to run. Fuel use rises with higher load.
- Fuel type
- Fuel choice changes burn rate; diesel is typically more efficient than gasoline/propane.
- Runtime hours
- Hours you plan to run the generator at the stated load.
How it works
Fuel burn scales with load. We use typical per-kW burn rates by fuel type to estimate gallons per hour and total fuel.
Formula
Fuel/hour ≈ Load (kW) × Fuel burn per kW Total fuel = Fuel/hour × Runtime hours
When to use it
- Planning fuel storage for outages or job sites.
- Comparing fuel cost between gasoline vs diesel vs propane.
- Estimating runtime before refueling based on tank size.
Tips & cautions
- Actual burn varies by generator efficiency and load swings; this is a ballpark estimate.
- For variable loads, average your expected load or run a few scenarios.
- Check manufacturer specs for precise burn rates at 25/50/75/100% load.
- Uses approximate per-kW burn rates; not manufacturer-specific.
- Assumes steady load; real-world loads fluctuate.
- Outputs in gallons; convert propane/natural gas units as needed for your tanks/meters.
Worked examples
8 kW load, diesel, 6 hours
- Fuel/hour ≈ 8 × 0.08 = 0.64 gal
- Total ≈ 3.84 gallons
Deep dive
Estimate generator fuel consumption by entering load, fuel type, and runtime to see gallons per hour and total fuel needed.
Use this to plan fuel for outages, job sites, or events and to compare fuel efficiency across generator types.
FAQs
- Are these burn rates exact?
- No—these are ballpark per-kW rates. Check your generator’s spec sheet for precise consumption at each load.
- How do I handle variable load?
- Estimate an average load or run several load scenarios to bracket fuel use.
- Does propane/natural gas use gallons?
- This tool outputs in gallons for simplicity. Convert to pounds/BTU/therms as needed using your supplier’s conversion.
- What about surge loads?
- Short surges won’t move the average much. For heavy sustained loads, increase the load input.
- Can I include tank size?
- Not yet. Compare total fuel output to your tank capacity manually to estimate runtime between refuels.
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Approximate consumption only. Verify with manufacturer data and monitor real-world fuel use for critical applications.