Glasses Frame Size Guide
Decode the 3 numbers on the inside of your frame. Find your PD (pupillary distance), match new frames to your face — for online ordering from Warby Parker, Zenni, EyeBuyDirect.
Find frame size from your face width
The 3 numbers on your frame — what they mean
Inside your current glasses (on the temple arm or bridge) you'll find a marking like "52-18-140". Three numbers separated by dashes/squares.
1. Lens width (first number, mm)
Width of EACH lens, eye-to-eye. Typical range: 40–58mm. Most adult frames are 50–54mm.
2. Bridge width (second number, mm)
The gap between the two lenses (over your nose). Range: 14–22mm. Higher bridges fit narrower noses, lower bridges fit wider/lower noses.
3. Temple length (third number, mm)
The arm length from hinge to ear-tip. Range: 130–155mm. Most adult arms are 140–145mm.
Bonus: lens height + total width
NOT in the standard marking. Lens height = 25–45mm typical. Total frame width = (2 × lens width) + bridge. Should match face width within 5mm for a good fit.
PD (Pupillary Distance) — what it is + how to measure
PD is the distance between your pupils in mm. Required when ordering glasses online. Standard PD: 60–65mm for women, 64–68mm for men.
How to measure your PD (DIY)
1. Stand 8 inches from a mirror. Look straight ahead.
2. Place a ruler horizontally just above your eyes.
3. Close your right eye. Align the "0" of the ruler with the CENTER of your left pupil.
4. Without moving the ruler, open your right eye and close your left.
5. Read the mm at the center of your right pupil. That's your PD.
💡 Many phone apps and Warby Parker / Zenni have PD-measuring tools that use your phone camera. More accurate than DIY ruler method.
Face shape → frame style
Round face
Choose angular frames: rectangle, square, wayfarer. AVOID round frames — they emphasize roundness.
Oval face (most flexible)
Almost any frame works. Try aviator, rectangle, oversized round.
Square face
Soft round or oval frames balance angular jaw. AVOID square frames.
Heart-shaped face (wide forehead, narrow chin)
Cat-eye, aviator, or bottom-heavy frames. AVOID embellished top rims (makes forehead look wider).
Diamond face (narrow forehead + jaw, wide cheekbones)
Cat-eye, oval, rimless. Decorative tops balance narrow forehead.
FAQ
Where can I order glasses with my prescription online?
Warby Parker ($95+), Zenni Optical ($7+), EyeBuyDirect ($6+), GlassesUSA, Costco. Most accept emailed prescriptions and PD entered manually. Some now use phone-based PD measurement apps.
Should I size up frames for the "oversized" look?
Up 4–6mm from your face width works. Going more than 8mm over makes glasses slip down constantly. Oversized requires proper temple length (often 145mm+) to stay on.
How do I know if frames will fit before ordering?
Compare the 3 numbers on your existing favorite glasses to the new ones. Within 2mm = will feel similar. Plus most online retailers have FREE home try-on (Warby Parker, Liingo, EyeBuyDirect).
What about kids' frames?
Kids' frame numbers are smaller across the board: 40–48mm lens, 14–17mm bridge, 125–135mm temple. Several online retailers carry kids: Jonas Paul Eyewear, RoshamboBaby, Zenni Kids.