Having accurate measurements on your marketing materials is a simple but essential factor for the working model. You’ll want to do your best to find lifestyle/routine that helps you maintain these numbers consistently. For some models, even small changes can make a big difference on if you are getting booked depending on the type of work you’re doing. Besides that, continually bouncing around in size will make it more difficult for your agent to be able to market you to their clients effectively.
The stats you will always need to know are height, dress/pants size, shoe size, and measurements for bust, waist, and hips. Additional measurements may be asked or taken for specific jobs/fittings but these are sufficient for listing on your comp cards.
Height is always measured bare foot from the top of your head (at the back, the highest point) to the floor. Be sure not to add additional hair height.
Dress size can vary brand to brand so go with whatever is most common or if it is between two go ahead and list both with a / between them.
Shoe size should be what you actually wear comfortably enough to stand/walk for at least a short time but that won’t slip or gap a bit.
Breast measurement goes around the fullest part of your breast. Do wear a bra when taking this measurement but, make sure it isn’t padded or a pushup and don’t take a huge breath in or collapse your chest/shoulders in when measuring.
Waist measurement should be taken at the most narrow part of your waist. It is higher than your belly button, just under your ribs. (The belly button area is known as your low waist. It isn’t included in your model measurements but may be taken in fittings.) Again, don’t take a deep breath in or suck in your stomach. Stand tall but relaxed.
Hips are the fullest part of your hips.
The tape should be pulled taught but not cutting into your flesh anywhere, just sitting lightly on top of it.
Keep in mind, it doesn’t server you to be dishonest (or even incorrect) because potential clients may take your measurements during your go see. Even if they don’t, models are booked or clothes are made/paired with models based on these numbers so having them wrong could mean you end up with garments that are ill fitting or possibly even nothing to wear!