How to measure for a body shape result
The calculator is only as good as the four numbers you give it. This guide puts the tape in the same place every time, and it names the mistakes that move a result across a boundary.
The four tape lines
Bust, waist, hip and high hip are all horizontal circumferences. The first three are familiar; high hip is the one most people have never taken. It sits between the waist and the fullest hip, at the level of the hip bones.
A 2021 study of 1,679 scans found that moving a measurement by about 1 cm changed the FFIT category for up to 40% of women. The goal here is not laboratory precision; it is consistency, so that the same body measured twice gives the same answer.
Bust
Wrap the tape around the fullest part of the bust, usually across the nipples, keeping the tape parallel to the floor. Stand with arms down and breathe normally. The tape should touch the body without pressing into it.
- Do not measure over a padded or push-up bra; use a soft, unpadded bra or bare skin.
- Do not pull the tape tight to “get the real number”. Compressing the tissue lowers the reading.
- Do check the back of the tape in a mirror; it often slips lower than the front.
Waist
The natural waist is the narrowest part of the torso, usually just above the navel and below the ribcage. Stand relaxed, breathe out, and measure without sucking in. If you cannot find the narrowest point, bend sideways; the crease that forms is a useful landmark.
- Do not measure where your jeans sit if that is lower than the natural waist.
- Do not measure immediately after a large meal or when bloated; the number will not be comparable.
- Do keep the tape level all the way around; a dipped back adds length and changes the reading.
High hip
Put your hands on the top of your hip bones (the iliac crests). The high hip is the circumference around that level, roughly 7–9 cm below the natural waist, before the body widens to the fullest hip. It is the measurement that separates Spoon from Bottom Hourglass and Triangle in the FFIT rules.
- Do not use the widest hip measurement; that is the fourth measurement, not this one.
- Do not guess from your jeans size; the high hip is a body circumference, not a garment measurement.
- Do measure twice. The high hip is the point where a small vertical shift changes the ratio the most.
Hip
Stand with feet together and measure around the fullest part of the hips and seat, usually about 18–23 cm below the waist. Keep the tape level and snug without compressing the body.
- Do not measure over a phone, wallet or keys in a pocket.
- Do not stand with feet apart; that changes the shape of the seat and the reading.
- Do check the tape at the back in a mirror; it is the side that drifts.
A two-reading protocol
- Measure all four points once, in the order bust → waist → high hip → hip.
- Wait a minute, then measure each point again without looking at the first number.
- If the two readings differ by 1 cm or less, use the average.
- If they differ by more than 1 cm, take a third reading and use the median.
- Enter the numbers in the same unit. The calculator converts centimetres to inches internally.
Common mistakes
| Mistake | What it does | Fix |
|---|---|---|
| Tape tilted at the back | Adds length to the circumference and can move the waist or hip reading. | Check the back in a mirror; keep the tape level. |
| Measuring over thick clothes | Adds fabric bulk, especially at the hip. | Measure over light clothing or bare skin. |
| Pulling the tape tight | Compresses soft tissue and lowers the reading. | Snug, not tight; the tape should not dig in. |
| Using a metal tape | Does not follow the body and gives a false reading. | Use a soft tailor’s tape. |
| Measuring alone and twisting | Moves the tape and shifts the landmark. | Use a mirror; ask for help if you can. |
What to do with the numbers
Enter bust, waist, high hip and hip in the calculator. If you leave high hip blank, the result will be a family rather than a specific shape; that is deliberate. The method page explains each rule, and the chart shows what the nine results look like side by side.
Measurement questions
Where exactly is the high hip?
Place your hands on the top of your hip bones. The high hip is the circumference around that level, roughly 7–9 cm below the natural waist, before the body widens to the fullest hip. It is not the same as the widest hip measurement.
Should I measure over clothes?
Measure over light clothing or bare skin, not over jeans or a padded bra. Keep the tape level and snug without compressing the body. If you measure twice and the numbers differ, use the average or take a third reading.
Why do my measurements change between days?
Bloating, posture, breathing, pregnancy and weight change all move the numbers. A shape is a snapshot of four circumferences, not a permanent identity. Re-measure when the result matters, and treat a borderline result as borderline.
What if my waist is larger than my hips?
That is a valid pattern. The 2020 revision includes Diamond and Oval for it. The calculator will not force you into Rectangle or Inverted Triangle, which is what the older seven-shape formulas often did.