Generator operating costs
Generator running cost calculator
No result yet. Enter your values, then calculate.
Method and printable worksheet
Inputs are your assumptions unless a document is supplied. Check source numbers and compatibility in the matching manufacturer manual.
Fuel cost interval = [q_low × p_low × hours, q_high × p_high × hours], for nonnegative quantities and prices in the same unit. Hourly cost = q×p; cost per 24-hour day uses 24 run hours only when explicitly selected. Add optional reserves/fees separately. Electricity cost per generated kWh needs actual average output kW: q×p/output_kW. Output must be greater than zero for a cost-per-kWh result. The calculator does not estimate fuel use between or beyond published load points.
Synthetic arithmetic check: q=0.4-0.6 gal/h, p=$3-$4/gal, h=10 gives 4-6 gallons and $12-$24 fuel cost. These are example rates, not current prices or model data.
| Item / exact model | Quantity and units | Low / running | High / starting | Source and date |
|---|---|---|---|---|
| Record 1 | ________ | ________ | ________ | ________ |
| Record 2 | ________ | ________ | ________ | ________ |
| Record 3 | ________ | ________ | ________ | ________ |
Worksheet: https://bestgeneratorforhome.com/how-much-does-it-cost-to-run-a-generator/generator-running-cost-calculator/
Review the planning guide. Check the exact manual before using any result. Report a method correction.
The short answer
The generator running cost calculator multiplies your documented consumption, matching local price and run hours. It returns a fuel-cost range. Enter the exact model, load point and source dates. Optional maintenance and fees stay separate; blank extras are excluded. This is an estimate from your assumptions, not a current price quote.
Last updated October 2026
What's covered11
- Generator running cost calculator default example
- Inputs at a glance
- How the generator running cost calculator works
- Why the stated load point matters
- Fuel type and rated output
- Local price and its date
- Fuel reference prices and their limits
- Maintenance and other costs
- Sources, method and limits
- Generator running cost calculator FAQs
- Generator running cost calculator verdict
This calculator estimates the fuel cost of a planned generator run. It uses fuel use per hour, fuel price and run hours. It returns a low and a high figure.
It does not know your model's burn rate. You supply that figure from a manual or your own measurement.
This tool estimates fuel cost for a run you plan. Enter fuel use per hour at a stated load from the manual or your own measurement. Then enter a dated local price in the same unit and your run hours. The result is a low-to-high fuel cost range. Maintenance and fees are optional separate entries. They are never counted as zero.
Generator running cost calculator default example
You can calculate without typing a gasoline price. The starting range is $4.3333 to $4.354 per US gallon. AAA reports the first value for national regular on October 14, 2026. EIA reports the second for October 5.
The bracket combines two dated references, not local low and high pump prices.
The starting use range is 0.4 to 0.6 gallons per hour for ten hours. Those are illustrative assumptions from the worked example, not a named model's consumption. Replace them with documented use at your load. Optional fees stay blank and excluded.
Changing fuel selects a matching reference example and unit. Changing to other units clears incompatible values. New units need their own documented price and rate.
Inputs at a glance
| Input | What to enter | If missing |
|---|---|---|
| Fuel and unit | Gasoline gallons, propane gallons or pounds, natural gas cubic feet or therms | No result |
| Fuel use per hour | Low and high values at a stated load, from a manual or your measurement | Unknown |
| Local price | Low and high price per matching unit, with the date checked | Unknown |
| Run hours | Hours you plan to run the generator | No result |
| Maintenance and fees | Optional amounts you enter yourself | Excluded and named as excluded |
Scroll for more →
Record the fuel unit beside both consumption and price. Keep the exact load point and source date with the rate. The result shows the entered assumptions as well as the calculated range. That record matters when you change a price, fuel or planned run time.
How the generator running cost calculator works
First, choose a fuel and its unit. The tool never mixes units on its own. A propane price per pound cannot be applied to fuel use in gallons. You need a documented conversion first.
Natural gas works the same way. Fuel use in cubic feet needs a price per cubic foot. Therms need a documented energy conversion before they match cubic feet.
Next, enter fuel use per hour as a low and a high value. Each value should come with the load it was measured at. Then enter a low and a high price per the same unit. Last, enter your run hours.
The tool multiplies the numbers in pairs. Low use times low price times hours gives the bottom of the range. High use times high price times hours gives the top. Quantities and prices cannot be negative.
Illustrative arithmetic example
This example shows the math only. It does not describe any real generator or market price. Say fuel use is 0.4 to 0.6 gallons per hour. Say price is $3 to $4 per gallon.
Run time is 10 hours.
Fuel used is 4 to 6 gallons. Fuel cost is $12 to $24. The hourly cost is $1.20 to $2.40.
Hourly, daily and per-kWh results
Hourly cost is fuel use per hour times price. A 24-hour cost appears only if you choose 24 run hours. The tool does not assume a full day on its own.
Cost per kWh needs actual average output above zero. A blank average-output field omits this optional result. Entering zero produces an error because division by zero is undefined. A generator's maximum watt rating is not automatically its average output during your run.
Watts measure power. Watt-hours measure energy over time. One thousand watts equals one kilowatt, and watts times hours gives watt-hours (Department of Energy style guide). Rated watts alone do not tell you fuel use.
Why the stated load point matters
Fuel use changes with load. Manufacturers often publish runtime at only a few load points. The initial burn example is illustrative. Replace it with a documented point for your model and load.
Honda lists the EU2200i at 3.2 hours of runtime at rated load. It lists 8.1 hours at quarter load. The gasoline tank holds 0.95 gallons (Honda EU2200i). The EU3000iS lists 6.9 hours at rated load and 19.6 hours at quarter load (Honda EU3000iS).
These are separate points for separate models. They do not reveal fuel use at other loads. The tool does not draw a line between points. It does not extend beyond published points either.
Two documented load points can provide context. They do not establish a verified curve between them. If you use them as low and high assumptions, label that choice clearly. A different actual load may fall outside your assumed range.
A measured or manufacturer-documented rate at your load gives a stronger basis.
Fuel type and rated output
Some generators run on more than one fuel. Their rated running watts can differ by fuel. Champion lists its 201176 tri-fuel inverter at 7,250 running watts on gasoline. It lists 6,525 watts on propane and 5,875 watts on natural gas (Champion 201176).
Westinghouse lists the WGen11500TFc at 11,500 running watts on gasoline. It lists 10,500 watts on propane and 9,500 watts on natural gas (Westinghouse WGen11500TFc).
These figures describe output, not fuel use. You still need a fuel use figure for the fuel you choose. Pair it with a price in that same unit.
This tool does not compare fuels on emissions, upkeep or engine life. Those questions need their own evidence.
Local price and its date
The EIA gasoline update publishes dated national and regional prices with units. Those are reference data, not a quote from your supplier. Gasoline prices begin with the dated AAA and EIA reference bracket above. Propane and piped gas have separate dated reference examples.
Other units still need a matching price. Use a local price whose date and scope match your plan.
Enter the price per unit that matches your consumption data. Record when you checked it. State whether taxes or delivery are included in that price. Do not add an already-included fee again.
A blank price prevents a result. It does not mean the fuel is free.
Fuel reference prices and their limits
Propane uses two national references in gallons. EIA reports $2.598 for residential propane on October 5, 2026. DOE AFDC reports $3.59 for retail motor-fuel propane in April 2026. Their dates and buying contexts differ.
The bracket is a planning scenario, not a home-delivery quote. Read the source notes before using it.
Piped gas uses EIA's 2025 annual and July 2026 monthly residential series. They report $15.34 and $26.45 per thousand cubic feet. Dividing by 1,000 gives a matching price per cubic foot. Both sources are from EIA; they are not independent providers.
They do not replace your tariff.
For these examples, the Generac sheet supplies half/full-load fuel use. Propane is 2.06/3.63 gallons per hour. Natural gas is 188/333 cubic feet per hour. These are model-specific points, not a curve between loads.
Replace the example with your own documented model and load.
Maintenance and other costs
Fuel is not the only cost of owning a generator. Scheduled service and fees can add more. This tool does not estimate them.
You can enter a maintenance reserve and fixed fees in separate fields. They are added to the fuel range and listed apart. If you leave them blank, the result is fuel only. Taxes and delivery stay excluded unless you enter them.
Sources, method and limits
Your inputs are user-entered assumptions or documented observations identified by your source notes. The outputs are derived from those entries. The explanation uses published model figures. The calculator does not verify a manual or a supplier quote on your behalf.
The method has clear limits. It does not predict load changes during an outage. It does not check wiring, transfer equipment or sizing. A cost result is not a compatibility result.
Interactive results need JavaScript. Without it, the formulas and a blank printable worksheet still appear. The page shows no result until required inputs are valid. Errors appear next to invalid units, negative values or mismatched fuels.
Cost is not the only planning question. Portable engine generators belong outdoors, at least 20 feet from the home. Point the exhaust away from the house. Never run them indoors or in a garage, even with doors open (CPSC).
Standby units follow their own manual and local rules.
To see how long a tank lasts, use the generator run time calculator. For other cost factors, read how much does it cost to run a generator.
Generator running cost calculator FAQs
Does the calculator know my generator's fuel use? No. You enter fuel use per hour from your manual or your own measurement. Each figure should name the load it applies to. The tool does not guess fuel use at unlisted loads. Without a figure, the result stays unknown. It never fills the gap with a default value.
Why is the result a range? Fuel use and local price can each vary. Low use at a low price sets the bottom. High use at a high price sets the top. One figure would hide that spread. The range shows how much your inputs could change the cost of the same planned run.
Can I include maintenance in the total? Yes, but only as a separate entry. The tool has no built-in maintenance figure. Enter your own reserve and any fixed fees. They appear apart from the fuel range. If you leave them blank, the result is fuel only. It does not mean maintenance is free.
Can I mix fuel units? No. Fuel use and price must use the same unit. Propane in pounds cannot pair with a price per gallon without a documented conversion. Natural gas in cubic feet needs a matching price. Therms need a documented energy conversion first. Otherwise, the tool reports an invalid unit error.
Generator running cost calculator verdict
Generator running cost calculator results depend on the exact inputs below.
This tool gives a useful fuel-cost range when your inputs are documented. Use fuel use at your stated load and a dated local price in the same unit. Add your planned run hours. If you lack any of these, the result stays unknown.
Keep maintenance separate, and treat the output as a planning range.
Continue your backup plan
Choose your next step
To put a fuel bill next to the purchase price, read the generator operating cost guide and follow its link to the home generator picks. Match the exact fuel, voltage and starting limits to your result before you choose.