Take your actual body measurements as they are more accurate than measuring over your clothes.

Collar: measure around the base of the neck where the collar sits.

Chest: measure the chest at the fullest part, placing the tape close up under the arms.

Waist: measure the natural waistline.

Inside Leg: measure from the crotch to where your trouser is normally worn on the shoe.

Jacket Length: measure from the centre back of your neck to your hemline. Then length measurement will vary depending on the style.