* Year: Older Mustangs generally have lower fuel economy than newer models.
* Engine: A V6 engine will be more fuel-efficient than a V8. A smaller displacement engine will also be better on gas than a larger one. EcoBoost engines generally offer better fuel economy than naturally aspirated engines of similar size.
* Driving style: Aggressive driving habits drastically reduce fuel economy.
* Driving conditions: City driving uses more fuel than highway driving.
You won't find a single answer. To get a precise estimate, you need to specify the year and engine of the Mustang convertible. Then, you can look up the EPA estimated MPG (miles per gallon) for that specific model. This information is usually available on the official Ford website, the EPA's fueleconomy.gov website, or various automotive review sites.
