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478 landmarks
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Height, arch and left/right balance
Brow symmetry test: are your eyebrows even?
Eyebrows rarely sit at identical height and arch position, and small differences are normal, but noticeable imbalance is one of the features people ask about most. This free brow symmetry calculator uses an AI face scan to measure height, arch peak position and left/right balance directly from your landmarks.
Free basic reports require no credit card, no account, no password. Your image is never uploaded or stored. Analysis happens in your browser and your session data is cleared when you close or refresh the page.
In short
Brow symmetry compares the height and arch peak position of your left and right eyebrow against the facial midline. Facemap reports a height difference, an arch position difference, and an overall balance score between 0 and 100.
- 3D landmarks
- 4783D landmarks
- Scan time
- ~20sScan time
- Uploads, runs in browser
- 0Uploads, runs in browser
- No account required
- FreeNo account required
Where it is measured
Brow symmetry on the landmark mesh.
The overlay is drawn from the same 478 point MediaPipe landmark set Facemap uses on your own scan, so every caliper, axis and node sits on the exact anatomy the measurement is taken from.
Sample reading, Height, arch and left/right balance
- Arch peak delta
- 1.2 mm
- Brow height delta
- 0.9 mm
- Peak position
- 0.68 lateral
- Symmetry index
- 94.8%
How the scan works
Capture
Guided front-on frame with even light, no upload.
Landmark
478 point mesh placed on your face in real time.
Report
Brow symmetry measured, normalised and explained.
What is brow symmetry?
Brow symmetry describes how closely your left and right eyebrow match in vertical height and in the horizontal position of the arch peak, measured relative to the facial midline.
How Facemap measures brow symmetry
Facemap tracks a series of landmarks along each brow ridge from the 3D face mesh, identifies the highest point of each brow, and measures its vertical position and horizontal distance from the midline. The left and right readings are then compared to produce a balance score.
What the typical range looks like
Small brow height and arch differences of a few millimetres are extremely common and usually not visible in a mirror. Larger differences, particularly in arch peak position, are more likely to be noticeable and are the most common source of a perceived uneven brow.
How to read your result
A high balance score means both brows sit at a similar height with the arch peak in a similar horizontal position. Lower scores usually trace to one brow sitting higher, or one arch peak sitting further outward than the other, both of which are common and typically unrelated to anything structural elsewhere in the face.
The brow symmetry formula: how we calculate it
Mirrored-pair residual across the brow region only. Landmark numbers are MediaPipe Face Landmarker indices, and every distance is normalised to your own face so camera distance and image size cancel out.
same residual as facial symmetry, restricted to the brow pairs
- Landmarks used
- 105/334, 70/300, 46/276, 107/336, 66/296
- Reference target
- 0
- Tolerance band
- 0.055
Your reading is compared with that published reference on a Gaussian match curve: score = round( 100 x exp( -0.5 x ( (reading - target) / tolerance )^2 ) ), clamped to 1 to 99. Basis for the reference value: region-restricted version of the whole-face residual. The headline Attractiveness Score works differently: all readings are corrected for head angle and expression, weighted by confidence and mapped onto a 1 to 100 scale by a model calibrated against a published research set of more than Facemap scans.
Read the full Facemap methodology, including how the 22 measurement categories combine into your Attractiveness Score.
Brow symmetry reference table
Brow symmetry score bands and how each one reads.
- 94 to 100Very balanced
Height and arch position closely matched
- 86 to 93Balanced
Minor difference, typically not visually noticeable
- 75 to 85Moderate difference
One brow sits visibly higher or arch differs
- Below 75Marked difference
Noticeable height or arch position gap
Height versus arch position, two separate readings
Brow imbalance can come from two independent sources, and Facemap reports them separately so you can see which one is driving your score.
- Vertical height difference between the two brow ridges
- Horizontal arch peak position relative to the midline on each side
- Brow length and thickness, which affect appearance but not the symmetry score
- Expression at rest, which can temporarily raise one brow
What causes uneven eyebrows
Brow asymmetry is extremely common and usually structural rather than a sign of anything else.
- Natural bone structure differences between the left and right brow ridge
- Habitual expression patterns that raise one brow more than the other
- Grooming and shaping differences built up over time
- Minor facial nerve tone differences, which are common and usually not clinically significant
Getting an accurate brow symmetry reading
Keep your face relaxed with no raised brow or frown, since expression is the most common cause of a false reading. Face the camera directly with hair clear of both brows, and use even lighting across the forehead so the arch peak on each side is placed consistently.
The brow symmetry formula, step by step
Brow symmetry is best understood as a test of offset direction as much as size. The formula takes the difference between left and right brow apex height, normalised to your face width, and reports it as a signed value rather than a single distance.
- Find the highest point, or apex, of the left brow and the right brow
- Measure the vertical height of each apex relative to a level reference line
- Subtract the right apex height from the left apex height to get the raw offset
- Divide that offset by your face width to normalise it across different scan distances
- A positive result means the left brow sits higher, a negative result means the right brow sits higher
Your reading
Measure your brow symmetry in about twenty seconds.
The scan runs in your browser. Nothing is uploaded, and free basic reports need no account.
Questions
Brow symmetry test: frequently asked questions
Is it normal to have uneven eyebrows?
Yes. Mild brow height and arch differences are extremely common and are rarely noticeable in everyday viewing conditions.
What causes one eyebrow to sit higher than the other?
Usually natural bone structure or habitual expression patterns. It is a common and generally structural difference rather than a sign of anything else.
What is the formula used for the brow symmetry test?
Facemap takes the left brow apex height minus the right brow apex height, then normalises that offset to your face width. A positive value means the left brow sits higher, a negative value means the right brow sits higher, and a value near zero reads as balanced.
How does the AI face scan judge brow symmetry?
Google's MediaPipe Face Mesh, a machine learning model, runs entirely in your browser and places 478 3D landmarks including the brow ridge. Nothing is uploaded, and the positive or negative offset it reports is a deterministic geometric result, not an opinion.
Does expression affect the brow symmetry score?
Yes, significantly. Raising or furrowing one brow will shift the reading, so the scan works best with a relaxed, neutral expression.
How is the arch peak position measured?
Facemap tracks landmarks along the brow ridge from the 3D face mesh, identifies the highest point of each brow, and measures its horizontal distance from the facial midline.
Do I need to remove makeup for this test?
It is not required, but brow makeup that changes the visible shape can shift landmark placement slightly, so a bare brow gives the most accurate reading.
Related tools
Measurements that read alongside brow symmetry.
Bilateral landmark balance
Facial symmetry face scan
We compare 478 corresponding landmarks across the vertical midline of your face, region by region, to quantify how closely each side mirrors the other.
Eye-axis inclination angle
Canthal tilt face scan
The upward or downward angle of the eye's outer corner relative to its inner corner, measured from the same 3D landmark set.
Upper lid to brow gap
Eye to brow distance face scan
The vertical gap between your upper lash line and the lower border of your brow, normalised to your own eye height so the reading transfers across face sizes.
Every tool