Using the common 30-day month, 180 days equal exactly six months. On a calendar basis, months vary from 28 to 31 days. If you use the Gregorian average month length of 30.44 days, 180 ÷ 30.44 ≈ 5.91 months—about five months and twenty-seven days. For billing or business purposes, many organizations still treat 180 days as six months in practice.