An R12 to R134a refrigerant conversion chart is a tool used to properly recharge or convert a vehicle air conditioning system based on the refrigerant type and operating conditions. R12 and R134a are the most common types of refrigerant gases uses in vehicle air conditioning systems.
Due to atmospheric ozone depletion, the Environmental Protection Agency requires all cars manufactured after 1994 to use R134a cooling systems. As of 2003, R12 refrigerant is no longer commercially available, so drivers of older cars often use a conversion chart to upgrade their air conditioning systems. R152a refrigerant is a less common alternative to R134a for vehicles.