How to take your body measurements

Updated on 2026-10-03

Your check-in compares your numbers with last month's, so the most important rule is to measure the same way every time. A centimeter of difference should mean your body changed, not that the tape sat somewhere else.

Before you start

  • If you can, measure in the morning, before eating and after using the bathroom.
  • Use a soft tape measure, the kind used for sewing.
  • Measure on bare skin, not over clothes.
  • Stand in front of a mirror so you can check that the tape is level all the way around.
  • Relax. Don't tense your muscles or pull your stomach in, and breathe normally.
  • Don't measure right after a workout: a pumped muscle measures bigger than it is the rest of the time.

Weight

Weigh yourself in the morning, before eating and after using the bathroom, on the same scale every time. Your weight moves through the day with food and water, so morning readings taken under the same conditions are the ones worth comparing.

In the app, the weight wheel opens on a reading your scale or watch recorded in the last 24 hours, if there is one, and otherwise on the last weight you logged. The chip under the wheel shows your last logged weight and its date.

Body fat and muscle mass

Both are optional. Add them only if you use a body-composition scale, and always the same one: two devices can disagree by several percent, so only readings from one device are worth comparing.

Body circumferences

Six measurements: chest, waist, hips, arm, thigh and calf. Every time, the tape should lie flat on the skin without squeezing it.

In the app, tap a measurement to open the tape, then drag it with your finger. The info icon next to each name shows the steps below with a picture. The tape opens at your last value, but a measurement only counts once you move the tape, so nothing goes into your report that you didn't measure. The tape uses your units: centimeters, or inches if you use imperial units.

Chest

  1. Stand straight and relax your shoulders.
  2. Place the tape around the fullest part of your chest.
  3. The tape should lie flat on the skin without squeezing it.

Waist

  1. Stand straight and relax your stomach without pulling it in.
  2. Place the tape around your waist at the level of your navel, parallel to the floor.
  3. Read the result after you breathe out normally, without holding your breath.

Hips

  1. Stand straight with your feet together.
  2. Place the tape around the widest part of your hips and buttocks.
  3. Keep the tape parallel to the floor and flat on the skin without squeezing it.

Arm (biceps)

  1. Let your arm hang relaxed at your side, without tensing the muscle.
  2. Place the tape around the fullest part of your upper arm, about halfway between your shoulder and elbow.
  3. Measure the same arm every time. If the two sides differ, set left and right separately.

Thigh

  1. Stand straight with your weight on both legs and your thigh relaxed.
  2. Place the tape around the fullest part of your thigh, just below your buttock.
  3. Measure the same leg every time. If the two sides differ, set left and right separately.

Calf

  1. Stand straight with your weight on both legs and your calf relaxed.
  2. Place the tape around the fullest part of your calf.
  3. Measure the same leg every time. If the two sides differ, set left and right separately.

Left and right

Your arm, thigh and calf each have a left and a right side. By default the app takes one value for both: measure one side and the number is saved for left and right. If your sides differ and you want to follow each one, open the measurement and tap Set left and right separately to get a tape for each side. Same value for both goes back to a single tape.

Whichever you choose, measure the same way next month. On the website, left and right are always separate fields.

Progress photos

Photos show changes a tape can't, and they are optional. The check-in asks for three:

  • Front - stand straight, arms at your sides.
  • Side - stand sideways, feet parallel.
  • Back - stand straight, arms at your sides.

Take them in the same spot, light and clothing every time, from the same distance and with the phone at the same height, so photos from different months line up. You can send the check-in with or without photos.

Tips

  • Always measure in the same place and under similar conditions so the results are comparable.
  • One check-in a month is enough. Day-to-day changes are mostly water and food, not progress.