Is the oil low in a car if only shows on one side of dipstick?

It depends on the design of the dipstick and the oil level in the engine. If the dipstick has two marks, one for "full" and one for "add," then the oil level is typically considered to be low if it is below the "add" mark. However, if the dipstick only has one mark, then the oil level is typically considered to be low if it is below the bottom of the dipstick. It is always best to consult the owner's manual for specific information on how to check the oil level in your vehicle.