Alcohol typically takes about 6 to 72 hours to leave the system, depending on the type of detection test used. Generally, alcohol can be detected in:

• Blood for up to 12 hours
• Breath for 12 to 24 hours
• Urine for 12 to 24 hours, and up to 72 hours or more after heavy use
• Saliva for up to 12 to 48 hours
• Hair for up to 90 days

The liver metabolizes alcohol at a rate where about one standard drink is processed per hour. The half-life of alcohol is about 4-5 hours, meaning it takes approximately 25 hours to be cleared completely from the body after drinking stops. Various factors like genetics, age, weight, amount drank, food consumed, and enzyme levels affect the rate of elimination and detection times.