Assuming you're 18 when you join, and the average time it takes to be promoted: * Private (E-2) - 18 (join + 6 months) * Private First Class (E-3) - 19 - (join + 1 year) * Specialist/Corporal (E-4) - 20 (join + 18 months) * Sergeant (E-5) - 22 (join + 4.2 years) * Staff Sergeant (E-6) - 27 (join + 8.5 years) * Sergeant First Class (E-7) - 32 (join + 13.6 years) * Master Sergeant/First Sergeant (E-8) - 35 - (join + 17 years) * Sergeant Major (E-9) - 39 - (join + 20.8 years) Or if you're talking officer, start at say age 23, and then add: