(0.3 of 1 octane) for 5 gallons. It comes in a 12 once bottle. It says it treats up to 16 gallons, but one bottle in 16 gallons of gas would have en increase of less then on tenth of an octane(.097 of 1 octane). It's just best to get high octane gas or use toluene. Toluene would be cheaper overall for the octane increased.