A Complete Guide on How to Measure Sunglasses Size

Selecting the right sunglasses size is important for both comfort and style. Ill-fitting sunglasses can cause discomfort, distract you from outdoor activities, and may even fail to protect your eyes adequately. A well-fitting pair, on the other hand, complements your facial features while ensuring the frames stay securely in place. By learning how to measure sunglasses size correctly, you can avoid common fit issues like pinching on the temples or sliding down your nose, resulting in a better overall experience.

How Are Sunglasses Measured?

• Lens width: This is the horizontal diameter of a single lens, measured in millimeters. Larger lenses provide more coverage and can offer better UV protection, but you should also match this size to your face shape.

• Bridge width: The bridge width refers to the distance between the two lenses, across the nose. This determines how the sunglasses rest on your face, particularly on the nose, and influences overall comfort.

• Temple length: Measured from the hinge to the end of the temple arm, this determines how securely the sunglasses fit over your ears. A proper temple length prevents slippage or discomfort.

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How To Measure Sunglasses Frame Size

1. Lens Width: To measure the lens width, use a ruler or caliper to measure horizontally across the widest point of one lens, excluding the frame. The lens width typically ranges from 40 mm to 60 mm. A smaller lens width works well for narrow faces, while a larger width is ideal for broader faces to provide more coverage.

2. Bridge Width: Measure the distance between the inner edges of the two lenses where they meet over the nose. This distance, known as the bridge width, determines how well the sunglasses sit on your nose. A smaller bridge width (14 mm to 18 mm) suits narrow noses or closely set eyes, while a larger bridge width (18 mm to 24 mm) is better for wider noses or widely spaced eyes.

3. Temple Length: The temple length is the total length of the arms that go over your ears. To measure, start at the hinge where the temple connects to the frame and measure to the tip, including the bend. Temple lengths generally range from 120 mm to 150 mm. If the arms are too long, the glasses may slide off your face, while shorter arms can feel tight behind the ears.

How To Know What Size of Sunglasses To Buy

The size of sunglasses you need depends largely on your face shape and personal preference. Here are some guidelines:

• Oval faces: Most frame styles work on oval faces, but aim for sunglasses that are as wide as or slightly wider than your face.

• Round faces: Opt for angular frames to add definition, and choose a wider lens width to elongate the face.

• Square faces: Rounded or oval frames help soften strong jawlines. A slightly larger lens width can balance facial features.

• Heart-shaped faces: Go for frames that are wider at the bottom, or rimless designs, to balance a broader forehead.

• Small faces: Stick to smaller, narrower frames that don’t overwhelm your features or look too large.

How To Read Sunglass Size Information on Frames

Most sunglasses list size information inside the temple arm in the format of three numbers, such as “55-17-140.” These numbers correspond to the lens width, bridge width, and temple length in millimeters. Knowing how to interpret these measurements helps you find the right fit without having to try them on. For example, a lens width of 55 mm is typically suited for medium-sized faces, while a 140 mm temple length indicates a standard arm length for an average adult. (See below).

Sunglasses Size Chart: Small, Medium, Large

This chart can be used as a guideline to find your perfect fit based on the lens width, bridge width, and temple length. 

How to Measure Sunglasses Size - Frequently Asked Questions

• What size sunglasses do I need? 

Choose sunglasses that match your face shape and personal style. Use the size chart to guide you based on your measurements.

• How to measure sunglasses size in mm? 

Measure the lens width, bridge width, and temple length using a ruler or caliper in millimeters.

• How are sunglasses measured typically in retail? 

Retailers often list three key measurements: lens width, bridge width, and temple length, all in millimeters.

• Can children wear adult-sized sunglasses if adjusted? 

It’s not advisable. Even if adjusted, adult-sized sunglasses may not offer a secure or comfortable fit for children.

• What do the numbers on my sunglasses mean? 

These represent the lens width, bridge width, and temple length, in that order, helping to determine the frame's size.

• How do I know if my sunglasses are too big or too small? 

If your sunglasses slide down your nose or pinch your temples, they may not be the right size. Opt for a size that stays securely in place without discomfort.