How to Measure Your Body: Shirt Length
Put the first end of the measuring tape at the base of the back of your neck and measure down your back to the point where you’d want the shirt to end. This point is usually the bottom of the buttocks, although you may want to go slightly longer if you plan to always tuck the shirt in, or slightly shorter if you plan to wear the shirt untucked. Round up to the nearest inch.
Standard Size Dress Shirt Length
If you’re not sure about measuring your body for shirt length, you can measure the length of a shirt that fits well, or use these general guidelines for shirts that are going to be tucked in: