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Generator fuel planner

Put a daily price on generator runtime.

Enter the generator size, how hard it usually works, daily runtime, and local gasoline price. The result is a broad planning estimate, not a meter reading for your machine.

Start with your numbers

Example, not live fuel data

About $5.25 per day

4,250 W · moderate load · 4 hours · $3.50 per gallon

The same fixed calculation powers the form below.

Your inputs

Four inputs. One clear estimate.

Start with the example, then replace each number with your generator label, daily routine, and local gasoline price.

Generator and daily use

Use rated running watts from the generator label or manual. Every result is a planning estimate.

Planning estimate

Fuel use and cost

Enable JavaScript to calculate an estimate.

Estimated burn rate
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Cost per day
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Cost per week
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Cost per 30 days
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This fixed planning curve is not a model-specific fuel lookup. Check your generator manual or measure actual use when the difference matters.

The method

A fixed curve with visible limits.

The calculation stays simple so you can compare scenarios. Generator design and operating conditions still matter.

  1. 01

    Enter rated running watts

    Use the rated or continuous output from the generator label or manual, not surge watts.

  2. 02

    Choose a broad load level

    Choose light, moderate, or heavy based on the appliances that normally run together.

  3. 03

    Add runtime and gasoline price

    Enter daily generator runtime and replace the example gasoline price with your local gasoline price.

  4. 04

    Read the planning estimate

    Review estimated gallons per hour and cost per day, week, and 30 days.

What the estimate means. The tool uses one fixed planning curve across generator sizes and the three broad load choices. It is not a lookup for a specific make or model. Actual fuel use changes with generator design, fuel, maintenance, altitude, temperature, and loads that cycle on and off.

Manufacturer context. Honda lists the EU2200i with a 0.95 gallon tank, 8.1 hours at one-quarter load, and 3.2 hours at rated load. Cummins lists the gasoline Onan QG 4000 at 0.5 gallons per hour at half load. These examples show model variation. They do not directly create the curve used here.

Honda EU2200i official specifications, accessed August 23, 2026. Cummins Onan QG 4000 official specification, January 2025, accessed August 23, 2026.

Choosing solar equipment for these loads? Use the Solar Sizing Planner to estimate array and battery capacity from your appliance use, location, and planning months. Keep that capacity estimate separate from this calculator's fuel-cost estimate.

Plan, then forecast

Compare generator cost here. Plan solar days in SunPlanner.

This calculator helps compare fuel-cost scenarios. SunPlanner estimates solar production for the array and location you enter.

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