⛽ Fuel Cost Calculator
Enter your generator's output and operating schedule to project total fuel expense.
How Much Does It Cost to Run a Generator?
Generator operating cost depends on three variables: how big the load is (watts), how many hours per day the generator runs, and the price of gasoline. Here is a real-world reference for the most common scenarios, assuming $3.75/gallon gasoline:
| Scenario | Load | Hours/Day | Daily Cost | 5-Day Outage |
|---|---|---|---|---|
| Essentials only | 2,500W | 16 hrs | ~$18 | ~$90 |
| + Window A/C | 3,800W | 16 hrs | ~$27 | ~$135 |
| + Central A/C | 5,500W | 16 hrs | ~$37 | ~$185 |
| Heavy load | 8,000W | 18 hrs | ~$64 | ~$320 |
Tips to Reduce Generator Fuel Costs
- Stagger high-draw appliances. Don't run the electric kettle, microwave, and space heater simultaneously. Turn off the A/C at night if temperatures allow.
- Reduce idle time. Shut the generator off when sleeping (if safe to do so with your appliance needs) or when away. An 8-hour overnight shutdown saves ~5–8 gallons on a 7,500W unit.
- Use LED lighting. A single 60W incandescent bulb vs. a 9W LED: 12 hours/day × 5 days = 3 kWh total. Across 20 bulbs, the savings add up to meaningful runtime reduction.
- Pre-cool your refrigerator. Refrigerators run more efficiently when starting from a cold temperature. Run it before an incoming storm to reduce average compressor cycling load.
- Consider dual fuel. Propane doesn't degrade in storage the way gasoline does. If you already own a propane grill or BBQ setup, a dual-fuel generator lets you use existing fuel sources.
Frequently Asked Questions
It depends on size and load. A common 7,500W generator running at 50% load uses about 0.75–0.85 gallons/hour. A smaller 3,500W unit uses ~0.4–0.5 gal/hr. At 100% load, consumption roughly doubles. Use the calculator above for a specific estimate.
Running 16 hours/day at ~5,000W actual load (67% of rated), a 7,500W generator burns approximately 0.7 gal/hr × 16 hrs = 11.2 gal/day. At $3.75/gal, that's ~$42/day or ~$294 for a 7-day outage. At higher fuel prices or heavier loads, budget $350–$450 per week.
Often yes. Natural gas rates average $0.80–$1.20 per therm nationally. Large standby generators (12,000–20,000W) use roughly 200–250 cubic feet of natural gas per hour at full load — about 2–2.5 therms. At $1.00/therm that's $2–$2.50/hr vs. $3–$5/hr for gasoline. The main advantage is unlimited runtime from a utility gas line — no refueling.