What is the Norwood scale?
The Norwood scale is the most widely used way to describe male pattern hair loss. It sorts it into seven main stages, from a full hairline at stage 1 to hair left mainly around the sides and back at stage 7. Dr O. T. Norwood published it in 1975, building on a 1951 classification by J. B. Hamilton, which is why you will also see it called the Hamilton-Norwood scale.
Male pattern hair loss is hereditary, and the American Academy of Dermatology calls hereditary hair loss the most common cause of hair loss worldwide. In men, its first sign is often a receding hairline or a bald spot at the top of the head. The Norwood scale tracks both: the early stages are about the front of the hairline, and the later stages bring in the crown and the top.
A stage is a description, not a diagnosis. It tells you roughly what your hairline looks like today. It does not tell you why, or how fast it will change.
How the Norwood scale test reads your photo
Everything happens in your browser. When you start a scan, two small models download to your device and run there:
- A face landmark model finds points across your face. From them the test takes your brow line, the point between your brows (the glabella) and the base of your nose.
- A hair model marks which parts of the photo are hair.
The test then walks up your forehead in 45 evenly spaced columns, from just past one outer eye corner to just past the other, starting a little above your brows. In each column it records where hair begins. Joined together, those points are your traced hairline, which is drawn on your photo in the result.
Two measurements come from that line, both in mid-face units: the distance from the point between your brows down to the base of your nose. Classical facial proportions put the forehead at about the same height, so a forehead of 1.0 is the textbook proportion. Measuring against your own face means the size of your head and of the photo do not change the result.
- Forehead height is how high the middle of your hairline sits above the point between your brows.
- Temple recession is how much higher your hairline sits at the temples than in the middle: the depth of the M.
The test reads your photo three times, from slightly different crops, and combines them. If the three readings disagree, it shows the range rather than pretending to be exact.
These models were built by Google’s MediaPipe team for photo effects and augmented reality, not for medical use, and their makers say so. We use them only to trace a line on a photo, and we treat the result as a cosmetic estimate.
How the stage is decided
These are our own rules of thumb, not clinical cut-offs. We publish them so you can see exactly how your result was reached.
| Closest stage | What the photo shows, in mid-face units |
|---|---|
| 1 | Temples less than 0.15 higher than the middle, and a forehead under 1.15 |
| 2 | Temples 0.15 or more higher than the middle, or a forehead of 1.15 or more |
| 3 | Temples 0.35 or more higher than the middle, or a forehead of 1.35 or more |
| 4 or beyond | A forehead of 1.5 or more |
Norwood scale chart: the stages at a glance
| Stage | What it usually looks like |
|---|---|
| 1 | Little or no recession at the temples |
| 2 | A small, even step back at the temples |
| 3 | Deeper recession at the temples, often called the first clearly visible stage |
| 3 vertex | Stage 3 at the front with thinning at the crown |
| 4 | More loss at the front and crown, with a band of hair between them |
| 5 | The band between front and crown is thinner |
| 6 | The band is gone, so front and crown meet |
| 7 | Hair remains mainly around the sides and back |
Our Norwood scale chart guide explains each stage in more detail.
What a front photo can and cannot tell you
From the front you can see the hairline and the temples clearly. You cannot see the crown or the band of hair across the top. That matters, because from stage 3 vertex onward the crown is what separates one stage from the next.
So the test reads stages 1, 2 and 3 from the front, and if your hairline sits further back than stage 3 allows, it says 4 or beyond and stops there. Calling it anything more precise would be a guess.
Big forehead or receding hairline?
They are easy to confuse in a single photo. A tall forehead with an even hairline is just proportion: the temples sit level with the middle and the line is smooth. A receding hairline is about the temples moving back, so the M gets deeper over time.
The test reports forehead height and temple recession separately for that reason. If your forehead is tall but your temples are even, a high stage comes from proportion rather than recession. The only way to tell a big forehead from a moving hairline for sure is to compare photos taken months apart. Our guide to mature and receding hairlines goes through the signs.
How to take the photo for the Norwood scale test
- Push your hair straight back off your forehead, or tie it back, so your hairline shows from temple to temple. Take off any hat, cap or headband.
- Face the camera with it at eye level, about an arm’s length away. Keep your head straight and your chin level.
- Relax your face. Raised or lowered eyebrows move the measurement.
- Use bright, even light from the front, such as facing a window. Avoid a single overhead light, which casts shadows on the forehead.
- Take the photo, or upload one, and wait a few seconds while the models run.
Why the test sometimes says it cannot measure
When the test cannot read your hairline reliably, it tells you why instead of guessing:
- No face, or more than one: only you, facing the camera.
- Head turned or tilted: look straight ahead with your chin level.
- Too far or too close: your face should fill a good part of the frame, with your whole hairline in view.
- Too dark, glare or blurry: even light and a steady camera.
- Hair over your forehead: push it back so the hairline shows.
- Very short, shaved or covered hair: the hair model needs hair to find. Close crops can fall below what it sees.
The hair model can also struggle with very fine flyaways and with styles made of long, thin pieces such as braids. If your result looks wrong, try a photo with your hair pulled back smoothly.
Norwood scale for women: the Ludwig scale
The Norwood scale was written for men. Women with pattern hair loss usually keep their front hairline and thin across the top, and the American Academy of Dermatology notes that a widening part is often the first sign. The Ludwig scale, published by E. Ludwig in 1977, describes that pattern in three stages. A front hairline photo is not the right tool for it.
What to do with your result
One photo is a snapshot. If you want to know whether your hairline is moving, take the same photo in the same light every few months and compare. Many hairlines step back a little at the temples in adulthood and then hold.
If you are worried, talk to a dermatologist. The American Academy of Dermatology says treatment for hereditary hair loss works better the earlier it starts. See a doctor sooner if hair loss is sudden, patchy, itchy or painful, or if your eyebrows or eyelashes are thinning too.
Track it in the HairLens app
The HairLens app scans your hair from five angles, including the crown a front photo cannot see, scores density zone by zone and keeps every scan, so you can see whether your hairline is moving or holding.