Sunglasses - Lens width, frame size, and face-shape match

A sunglasses size calculator is a fitting tool that takes four face measurements - forehead width, cheekbone width, jawline length, and face length - and turns them into a recommended lens width in millimetres, a Small/Medium/Large frame size label, and a face shape reading with matching frame style picks. The same four face measurements also feed the face shape label, so this sunglasses size calculator gives you lens width and styling in one go.

• • Choosing lens width before buying: Get a recommended lens width in millimetres so the new pair covers your eyes without sitting too wide or too narrow.
• • Reading the size number on the temple: Match the recommended lens width to the three numbers printed on a sunglasses temple, like 52-18-140, and shop the right range on retail sites.
• • Picking a frame style for your face: Read the face shape label (oval, round, square, heart, diamond, oblong, triangle) and use the frame style list to narrow the buying decision.

Sunglasses are sized by lens width, bridge width, and temple length, and the lens width is the number that changes the most across adult face sizes. A pair that is too narrow sits on top of the cheekbones and lets light in.

For a personal fit and proportion reading, our body shape calculator uses the same kind of measurement-to-shape workflow on bust, waist, and hip, so the four face landmarks above pair naturally with a body proportion tool that turns personal measurements into a styling label.

The calculator blends the cheekbone width and face length into a single recommended lens width, then nudges that number up or down for soft versus sharp features. It also reads the four measurements the way the face shape calculator does, so the face shape label here matches what users get from that page.

• cheekboneWidth: Width across the most prominent part of the cheekbones, in centimetres. Carries the heaviest weight because cheekbone width most directly controls how wide a lens needs to be.
• faceLength: Vertical distance from the centre of the hairline to the tip of the chin, in centimetres.
• featureSharpness: Self-rated 1 to 5 score, where 1 is soft and rounded and 5 is sharp and angular. Each step above 3 trims 0.5 mm off the recommendation because sharper features can carry a smaller lens visually.
• foreheadWidth and jawlineLength: Used by the face-shape rule table only, not by the lens width blend.

The lens width result is rounded to the nearest 1 mm and capped inside the 49 to 63 mm adult band that Zenni Optical and eyeBuyDirect publish. Below 55 mm reads as Small, 55 to 58 mm reads as Medium, and 58 mm and up reads as Large.

According to Zenni Optical, the standard adult sunglasses lens width band runs from 49 to 63 mm, and the three numbers printed on a sunglasses temple read lens width, bridge width, and temple length in millimetres.

According to Zenni Optical - How to measure eyeglass frame size, the standard adult sunglasses lens width band runs from 49 to 63 mm, and the three numbers printed on a sunglasses temple read lens width, bridge width, and temple length in millimetres.

If you want a fuller face-shape reading with hairstyle and bang styling tips, the face shape calculator runs the same four-landmark rule table and adds a styling guide for each of the seven shapes.

Four ideas show up every time you read a sunglasses size chart. They are the same landmarks opticians and stylists use, and the calculator uses them too.

Lens width and bridge width are the two numbers that decide whether a pair sits correctly. Lens width controls eye coverage, and bridge width controls whether the frame sits flat on the nose or pinches.

The face shape calculator in our health and fitness cluster runs the same rule table on the same four measurements and adds the styling notes.

The Small, Medium, and Large language is the same convention used for skeletal frame size, and our body frame size calculator maps height and wrist circumference into a small, medium, or large frame index, so the lens width band and the body frame band line up the same way.

Four measurements and a sharpness rating are all the sunglasses size calculator needs. Work through the steps below with a soft tape and a mirror.

1. 1 Pick up a soft tape and a mirror: A flexible sewing tape is best because it follows the curve of the face. Use a mirror in good light and tie long hair back.
2. 2 Measure forehead width: Hold the tape across the widest part of the forehead, just above the eyebrows, and read it to the nearest 0.1 cm.
3. 3 Measure cheekbone width: Measure from the most prominent point of one cheekbone to the other, just below the outer corner of each eye. Keep the tape level.
4. 4 Measure jawline length: Place the tape at the corner of the jaw just below the ear on one side and run it to the tip of the chin. Average the two sides.
5. 5 Measure face length: From the centre of the hairline straight down the centre of the face to the tip of the chin. Keep the tape vertical.
6. 6 Set feature sharpness and sex: Pick 1 for very soft, rounded features, 3 for average contours, and 5 for very sharp, angular features. The sex select only changes the recommended frame style list.

A reader who measures forehead 14 cm, cheekbones 13 cm, jawline 9 cm, and face length 18 cm and selects sharpness 5 sees a 49 mm lens width, a Small frame size, and a Heart face shape.

When you want a vision-health reading to pair with the lens width, the 2020 vision calculator scores diet, activity, and smoking into a lifestyle visual-impairment risk label, so the eye-coverage fit check on this page and the eye-health risk check on that page cover both sides of buying sunglasses.

A lens width number and a face shape label are the two pieces of information you need before you buy sunglasses. The sunglasses size calculator gives you both at once, which saves a separate styling lookup.

• • Lens width without a tape on a frame: Read a recommended lens width in millimetres from face measurements alone.
• • Frame size band in plain language: Translate the millimetre result into a Small, Medium, or Large label using the 55 mm and 58 mm break points.
• • Face shape matched to frame style: Pair the face shape label with a recommended frame style list so the styling decision is grounded in the same four measurements that drive the lens width.
• • Temple string translation: Match the recommended lens width to the first number in a 52-18-140 style temple string, so the output lines up with the format used on retail product pages.

Because the calculator uses the same four-landmark face measurements as the face shape calculator, the two pages do not disagree on shape. You can re-enter the four numbers into the face shape calculator and the labels will match.

When you cross-check the lens width against body proportions, the lens width band and the body frame size band both use the same Small, Medium, and Large language, so a frame shopping plan can be read off either tool without retraining your eye.

A few real-world factors can move the result by a millimetre or change the face shape label by one category. Knowing them keeps the recommendation honest.

• • The calculator returns a single lens width number, not a full frame fitting. Bridge width, temple length, and pantoscopic tilt still need to be cross-checked against the product listing and a mirror.
• • The face shape label is a styling convention, not a medical or cosmetic assessment. The result is a starting point for frame choice, not a verdict on how the face should look.

Even with a perfect measurement, the lens width is the first of several checks. The bridge number on the temple string and the temple length both need to fit, and the only way to confirm the full fit is to try the frame on.

According to eyeBuyDirect - Eyeglasses Size Guide, a lens width under 55 mm reads as Small, 55 to 58 mm as Medium, and 58 mm or larger as Large.

According to American Optometric Association - Protecting your eyes from the sun, sunglasses that block 99 to 100 percent of UV-A and UV-B radiation are the standard for safe everyday use, so the calculator reminds users to check the UV block label even when the lens width is correct.

Because weight change rounds or sharpens facial contours, our BMI calculator shows how height and weight map to a weight category, so a re-measurement every few months can be paired with a BMI check to decide whether the recommended lens width has drifted up or down.