Sunglasses Size
Find your ideal sunglasses size and face shape with this free calculator. Enter forehead, cheek, jawline, and face length for recommended lens widths.
About This Calculator
Our Sunglasses Size Calculator helps you find the perfect frame fit by analyzing your unique facial measurements. Instead of guessing which size looks best, you can use science-backed face shape detection to narrow down your options. Whether you are shopping online or in-store, knowing your face shape and recommended lens width eliminates the guesswork from finding sunglasses that complement your features.
How Sunglasses Sizing Works
Sunglasses sizing is based on three key measurements printed on the frame: lens width (the horizontal width of each lens in millimeters), bridge width (the space between lenses), and temple length (the arm length). The lens width is the most important for fit. This calculator determines your face shape by comparing the ratios of your forehead, cheek, jawline, and face length measurements. Based on your face shape, it recommends frame shapes that complement your features and calculates an ideal lens width range from your average face width. Face shapes generally fall into seven categories: oval, oblong, round, square, heart, diamond, and triangle. Each has distinct frame shapes that work best for a balanced, flattering look.
How to Measure Your Face
Take measurements with a flexible measuring tape in front of a well-lit mirror. Tie back long hair for accuracy. For forehead width, find the widest point between your hairlines and measure across. For cheek width, measure the distance from the outer corner of one eye to the other. For jawline length, place the tape under your ear at the jaw corner and bring it to the chin tip; do this on both sides and average the values for the best accuracy. For face length, measure from the center of your hairline straight down to the bottom of your chin. Write down all four measurements before entering them into the calculator.
Regional Notes
United States: Sunglasses sizes are listed in millimeters on the inside of the temple arm (e.g. 52-18-140). Most adult faces fit medium to large sizes. Popular brands like Ray-Ban, Oakley, and Warby Parker provide comprehensive size guides. United Kingdom: UK retailers use the same international sizing system. The average UK adult face is similar to US measurements. High street opticians offer free frame fitting services. India: International brands use standard mm sizing. Local eyewear brands may use S/M/L categories instead. Online retailers increasingly offer virtual try-on features that work with your face measurements for accurate frame recommendations.
Tips for Buying Sunglasses
Always verify that your chosen sunglasses provide 100% UV-A and UV-B protection regardless of lens color or darkness. Polarization reduces glare but is not a substitute for UV protection. Consider getting the largest comfortable frame that fits your face for maximum eye coverage. When shopping online, measure a pair of sunglasses you already own and compare the lens width and frame width to the product specifications for the best fit.
Frequently Asked Questions
How do I measure my face for sunglasses?
Use a flexible measuring tape in front of a mirror. Measure forehead width at the widest point between hairlines. Cheek width from the outer corner of one eye to the other. Jawline length from below the ear to the chin tip. Face length from the center of the hairline to the bottom of the chin.
What does the lens width number mean on sunglasses?
The lens width is the horizontal width of each lens at its widest point, measured in millimeters. Typical lens widths range from 49 mm to 63 mm. Small frames have lenses under 55 mm, medium frames range from 55 to 58 mm, and large frames are 58 to 63 mm.
How do I know if my face is oval, round, or square?
Oval faces are longer than wide with cheekbones slightly wider than forehead and jaw. Round faces have similar width and length with subtle rounded hairlines and jawlines. Square faces have a strong horizontal jawline with similar width and length. This calculator detects your face shape automatically from your measurements.
What sunglasses suit an oval face?
Oval faces suit most frame shapes including square, rectangular, geometric, cat-eye, and horn-rimmed frames. Avoid oval or round frames that can make the face appear too long. The balanced proportions of an oval face allow for versatile frame choices.
What sunglasses suit a round face?
Round faces look best with angular frames such as rectangular, geometric, D-frames, wayfarer, and cat-eye styles. These shapes add definition and contrast to soft facial curves. Avoid round or oval frames that make the face appear rounder, and rimless styles that lack structure.
What sunglasses suit a square face?
Square faces benefit from soft, curved frames like round, oval, brow-line, rimless, and cat-eye styles. These soften angular jawlines and add balance. Avoid square or rectangular frames that emphasize strong facial angles. Round and oval shapes create a flattering contrast.
Is UV protection important when buying sunglasses?
Yes, always look for 100% UV-A and UV-B protection or UV400 rating on any sunglasses purchase. Dark lenses without UV protection can be more dangerous than no sunglasses at all because pupils dilate in the dark, allowing more UV rays to reach the retina. Polarization reduces glare but does not equal UV protection.
Can I use these measurements for buying sunglasses online?
Yes, the recommended lens width helps you filter online sunglasses by size. Check the product specifications for lens width and frame width measurements. Compare with your old sunglasses for reference. Many online retailers provide virtual try-on tools that work with standard face measurements.