Shopping for eyeglasses online but not sure what frame size fits your face? Don’t worry, you don’t need fancy tools or a tape measure. All you need is a standard credit card and a mirror (or your phone’s selfie camera).
Yes, really.
This simple trick will help you determine your face size so you can pick glasses that fit comfortably and look great.
Why Frame Size Matters
Just like clothing, eyeglasses come in different sizes. Wearing the wrong size can affect both your comfort and your look. Too tight? Headaches and pressure marks. Too loose? Constant slipping. A proper fit enhances your style and your everyday comfort.
What You Need
- A standard credit card (or any card that’s 3.37 inches / 8.56 cm wide)
- A mirror or your phone’s front-facing camera
How to Measure Your Face with a Credit Card
Follow these simple steps:
- Face a mirror or turn on your front-facing camera.
- Hold the card vertically against the center of your nose.
The bottom edge should sit on the bridge of your nose, and one side of the card should align with the middle of your nose. - Look at where the outer edge of the card ends on your face.
What Your Measurement Means
Here’s how to interpret it:
| Where the edge of the card lands | Likely Frame Size |
|---|---|
| Ends before the outer edge of your eye | Small (lens width ≤ 48mm) |
| Ends exactly at the outer edge of your eye | Medium (lens width 49–54mm) |
| Extends beyond the outer edge of your eye | Large (lens width ≥ 55mm) |
This trick is based on the average dimensions of adult facial structures, and while it’s not exact, it’s a great starting point.
Pro Tip: Check Your Current Glasses
Already wear glasses? Look at the inside of the temple arm. You’ll usually find three numbers printed there, like:
52-18-140
These refer to:
- Lens width (in mm)
- Bridge width
- Temple length
Use those as a reference when shopping for a new pair.
Final Thoughts
The credit card method is a quick and easy way to get a rough idea of your frame size, perfect for online eyewear shopping. While it’s not as precise as a professional fitting, it gets the job done in under a minute.
Still unsure? Many online eyewear retailers offer virtual try-ons or free returns, so you can test out your look without commitment.
Need more tips? At Main Frame Eyewear, we’re all about helping you find the perfect fit. Check out our frame guides, cleaning tools, and accessories to keep your specs looking sharp and feeling comfortable.
