Generator Cost Calculator
The sticker price is only part of what a generator costs. Installation, routine maintenance and fuel can add up to more than the machine itself over its life. This calculator spreads every cost over the years you will own the generator. It shows your true annual cost, the cost per hour of backup power and the cost per kWh you produce.
Generator Cost Calculator
Combine purchase, installation, maintenance and fuel to see what a generator really costs per year, per hour of use and per kWh.
Purchase and installation are spread evenly over the service life. Fuel use is estimated from typical consumption curves for the generator type.
How the cost is calculated
- Upfront cost = generator price + installation and accessories
- Annual fuel = fuel per hour × fuel price × running hours per year. Fuel per hour uses the same model as our fuel consumption calculator.
- Annual cost = upfront cost ÷ service life + maintenance + annual fuel
- Cost per running hour = annual cost ÷ running hours
- Cost per kWh = annual cost ÷ (rated kW × load × running hours)
The calculation ignores financing, inflation and resale value to keep the comparison simple.
Worked example: portable vs home standby
| 7.5 kW gasoline portable | 22 kW natural gas standby | |
|---|---|---|
| Generator price | $1,000 | $6,000 |
| Installation and accessories | $800 (interlock, inlet, cord) | $6,000 |
| Maintenance per year | $75 | $300 |
| Service life | 10 years | 20 years |
| Hours per year, average load | 100 h at 50% | 100 h at 40% |
| Fuel price | $3.20/gal | $1.50/therm |
| Fuel per year | $228 | $286 |
| Annual cost | about $483 | about $1,186 |
| Cost per running hour | $4.83 | $11.86 |
| Cost per kWh produced | $1.29 | $1.35 |
The standby unit costs about two and a half times as much per year, but it starts automatically, runs the whole house including central air, and needs no refueling. Whether that is worth it depends on how often your power goes out and what an outage costs you.
Typical cost ranges
| Item | Typical U.S. range |
|---|---|
| Inverter generator, 2–4 kW | $500 – $2,000 |
| Portable generator, 5–10 kW | $700 – $2,500 |
| Home standby, 10–26 kW (unit only) | $3,500 – $8,000 |
| Interlock kit and inlet box, installed | $500 – $1,000 |
| Manual transfer switch, installed | $600 – $1,500 |
| Standby installation (pad, gas line, transfer switch, permit) | $3,000 – $10,000+ |
| Annual maintenance, portable | $50 – $150 DIY |
| Annual maintenance, standby (dealer service) | $200 – $500 |
Prices vary by region, brand and site conditions, so get local quotes before you decide. Installing a generator connection safely is covered in our guide to connecting a generator without a transfer switch.
Frequently asked questions
Is it cheaper to run a generator or use grid power?
Grid power is far cheaper. U.S. residential electricity averages around 15 to 20 cents per kWh, while generator electricity typically costs 50 cents to several dollars per kWh once fuel and ownership are included. Generators make sense as backup, not as a replacement for the grid.
How many hours a year should I enter?
Add your expected outage hours to exercise time. Standby generators typically run a 5 to 20 minute self-test every week (roughly 5 to 17 hours a year), and portables should be started monthly. In areas with frequent storms, 50 to 200 outage hours a year is common.
Which fuel is cheapest to run?
Per unit of energy, natural gas is usually cheapest, followed by diesel, gasoline and propane, but local prices vary a lot. Switch the fuel type in the calculator to compare with your own prices.
Related tools and guides
- Generator Fuel Consumption Calculator
- Electricity Cost Calculator: compare with grid power
- How long do generators last?
- All calculators