When a car is in a parking state, such as idling with the engine running, it still consumes fuel, but the amount is generally quite low compared to when it's actively driving.
The gas consumption at idle can vary depending on factors like the car's engine size, whether it's a gas-powered or hybrid vehicle, and how efficiently the engine is. On average:
A typical gasoline-powered car consumes about 0.2 to 0.5 gallons per hour while idling.
For more fuel-efficient vehicles, the consumption could be closer to the lower end of that range.
So, while idling, your car might use between 0.005 to 0.01 gallons per minute. This can add up if you leave the engine running for long periods of time.
If you're looking to minimize fuel consumption, it’s usually best to turn off the engine if you’re going to be parked for more than a minute or so (unless you need the AC or other systems running).