What is 3'9" in inches? The answer is that 3 feet and 9 inches equal 45 inches.
The conversion formula for feet to inches is in = ft × 12. Based on this conversion formula, to convert 3 feet and 9 inches to inches, you need to multiply 3 feet by 12 to convert to inches, and then add 9 inches to this result.
3'9" = (3' × 12) + 9"
= 36" + 9" = 45 inches