- Idling a typical passenger car burns 0.16 to 0.30 gallons per hour, costing $0.50 to $0.93 per hour at $3.10/gallon.
- A large truck or SUV burns 0.40 to 0.70 gallons per hour at idle, costing $1.24 to $2.17 per hour.
- The DOE estimates that personal vehicle idling wastes approximately 3 billion gallons of fuel per year in the United States.
- Turning off your engine for stops longer than 10 seconds saves fuel compared to idling, according to DOE data.
01 How Much Fuel Does Idling Burn?
The DOE reports that idling fuel consumption depends primarily on engine displacement. A larger engine burns more fuel at idle because it must maintain a higher minimum air-fuel flow to keep running. The general relationship is approximately 0.1 gallons per hour per liter of engine displacement.
DOE, Office of Energy Efficiency & Renewable Energy, "Idling Reduction for Personal Vehicles," fueleconomy.govThis means a 2.0-liter four-cylinder engine burns roughly 0.2 gallons per hour at idle, while a 5.0-liter V8 burns approximately 0.5 gallons per hour. Actual rates vary with engine load (AC, electrical systems), engine temperature, and whether the vehicle is in gear.
DOE, fueleconomy.gov, "Idling"; Argonne National Laboratory idling fuel consumption studies02 Cost by Vehicle Type
The table below shows estimated idling fuel consumption and cost for different vehicle types, based on typical engine sizes and DOE fuel consumption rates.
DOE idling consumption rates applied to typical engine sizes by vehicle class; EIA gasoline price reference| Vehicle Type | Typical Engine | Idle Rate (gal/hr) | Cost/Hour ($3.10/gal) | Cost/Minute |
|---|---|---|---|---|
| Compact car | 1.5–2.0L | 0.16–0.20 | $0.50–$0.62 | ~$0.01 |
| Midsize sedan | 2.0–2.5L | 0.20–0.26 | $0.62–$0.81 | ~$0.01 |
| Small SUV | 2.0–2.5L | 0.20–0.26 | $0.62–$0.81 | ~$0.01 |
| Midsize SUV | 2.5–3.5L | 0.26–0.36 | $0.81–$1.12 | ~$0.02 |
| Large SUV | 3.5–5.3L | 0.36–0.54 | $1.12–$1.67 | ~$0.02 |
| Full-size pickup | 3.5–5.7L | 0.36–0.58 | $1.12–$1.80 | ~$0.02 |
| Heavy-duty pickup | 5.7–6.7L | 0.58–0.70 | $1.80–$2.17 | ~$0.03 |
While the per-minute cost seems small ($0.01 to $0.03), it adds up quickly. A driver who idles for just 10 minutes per day in a midsize SUV wastes roughly $0.20 per day, or about $73 per year.
Estimate your vehicle's driving cost using official EPA fuel economy data.
Use the Calculator03 Annual Fuel Waste from Idling
At the national level, the DOE estimates that personal vehicle idling consumes approximately 3 billion gallons of fuel per year. When commercial vehicles are included, the total rises to over 6 billion gallons. At $3.10 per gallon, this represents roughly $9.3 to $18.6 billion in wasted fuel annually.
DOE, Office of Energy Efficiency & Renewable Energy, Idling Reduction Program. This specific national total is not yet independently cross-checked against a file in our source data: see this article's disclaimer.Common idling situations include:
- Drive-through lanes. Average wait times of 5–10 minutes.
- Warming up the engine. The DOE states that modern fuel-injected engines need no more than 30 seconds of warm-up, even in cold weather.
- Waiting in parking lots. Picking up passengers, waiting for appointments, etc.
- Traffic congestion. Stop-and-go traffic involves significant idling time, especially in urban areas.
04 When to Turn Off Your Engine
The DOE recommends turning off your engine whenever you expect to be stopped for more than 10 seconds. Restarting a modern engine uses less fuel than 10 seconds of idling, and the wear on the starter and battery from additional restarts is minimal with modern components.
DOE/EPA, fueleconomy.gov, "Idling": "Turn off your engine if you will be waiting for more than 10 seconds"Exceptions include situations where the engine is needed for safety (e.g., power steering and braking in traffic) or where turning off the engine would create a hazard. The advice applies primarily to voluntary idling during stops and waits.
05 Automatic Stop-Start Systems
Many modern vehicles include automatic stop-start systems that shut off the engine when the vehicle comes to a complete stop (e.g., at traffic lights) and restart it when the driver releases the brake. The EPA accounts for this technology in its fuel economy testing.
EPA, 40 CFR Part 600: fuel economy testing procedures accounting for stop-start systemsAccording to the EPA Automotive Trends Report, stop-start technology can improve fuel economy by 2% to 5% in city driving, where frequent stops mean significant time spent idling. The technology has been adopted by over 40% of new vehicles as of 2023, the most recent model year for which this site has independently verified the adoption figure.
EPA, The 2025 Automotive Trends Report (EPA-420-R-26-001): stop-start technology adoption rate and fuel economy benefit estimates (model year 2023 figure)06 Data Sources
- DOE/EPA: FuelEconomy.gov – "Idling." fueleconomy.gov
- DOE: Office of Energy Efficiency & Renewable Energy, Idling Reduction Program. energy.gov
- EPA: The 2025 Automotive Trends Report (EPA-420-R-26-001). epa.gov/automotive-trends
- EIA: Weekly Retail Gasoline and Diesel Prices. eia.gov