Accurate body measurements are needed to determine the correct pattern size to use and whether alterations are necessary.
It is extremely important to take proper body measurements to ensure a proper fitting garment.
Depending on what your sewing project is, your pattern size will generally be determined by the hip or bust measurements on the pattern envelope.
Blouses and tops follow the bust measurement; however, skirts or pants use the hip measurement.
If you're selecting a dress pattern, go by whichever measurement is the largest.
In order to take proper body measurements you will need the following items:

• Plastic measuring tape
• Ruler
• Someone to assist you with taking certain measurements
• Wear close fitting clothes such as leggings and a leotard
• Pen and paper to record your measurements

Follow these quick steps on how to take proper body measurements: Height Measurements:

• Remove your shoes.
  
• Stand up straight with your back up against the wall.
  
• Place a ruler flat on top of your head.
  Make sure that the ruler is touching the wall and mark the wall at the point.
  
• Now step away from the wall and measure the length from the floor to the marked point.
  

FYI: You should first start off by taking your height measurement.
Most paper patterns are designed for women with heights ranging from 5 feet 5 inches to 5 feet 6 inches.
If you are taller or shorter than these measurements, please keep in mind that you will more than likely have to adjust your pattern before cutting your fabric.
Chest Measurements

• When taking chest measurements, measure above the bust, high under the arms, keeping the tape measure flat and straight across your back.
  

Full Bust Measurements

• Make sure that you are wearing a good fitting bra (first and foremost).
  
• Measure the fullest portion of your bust line.
  
• Make sure that the measuring tape is flat across and straight across your back.
  

Waist Measurement

• When taking your waist measurement, you will measure the smallest portion of your waistline.
  

Hip Measurement

• When taking your hip measurement, you will place your measuring tape around the fullest portion of your hips.
  This area should also include a portion of your buttocks area as well.
  

Outside Leg Measurement

• You may need some assistance in order to take this measurement properly.
  Starting from your waistline, use your measuring tape to measure the outside of your leg all the way down to your ankle.
  

Inside Leg Measurement

• You will need some assistance for taking this measurement.
  Stand with your legs apart and have your helper measure the inside of your leg starting at the crotch all the way down to your ankle.