Sunglasses Categories Explained

sunglasses explained

Sunglasses categories matter. This isn’t just about how dark they look but about ensuring you can enjoy comfortable vision, without squinting, whatever the weather.

So which category of sunglasses is right for you? Before we dive into that, here’s a quick explainer on sunglasses categories.

What are sunglasses categories?

These refer to the darkness of the lens tint in your sunglasses.

Categories range from very light (category 0) to very dark (category 4). The darker the tint, the more light the lens absorbs — this can be exactly measured, which is how different lenses end up in different categories.

And now for the science bit.

The measurement used for each category is called the ABS% and refers to the amount of visible light the lens absorbs. This ranges from 0 to 100%. However, as 100% would absorb almost all visible light, which would make seeing very difficult, even the darkest sunglasses lenses only have an ABS% of around 92%.

Colour doesn’t matter

It is important to note that the colour of your tint doesn’t affect the lens darkness category. Tints are available in a range of different colours — including blue, brown, green, grey or red — across categories.

And now to the categories themselves and how they affect your vision.

Category 0 — very light

The ABS% is from 0–10%. This offers no to very mild tinting, and so absorbs very little visible sunlight. This means category 0 glasses aren’t actually sunglasses. Standard prescription glasses that are clear fall into category 0.

You can wear these when driving during the day or night.

Category 1 — light

The ABS% is from 10–20%. Although these absorb more visible sunlight than category 0 glasses, they still aren’t that helpful on sunny days. They are most often worn on low-sun or overcast days by people with sensitive eyes. Consequently, these don’t count as sunglasses either.

You can wear these when driving during the day but not the night.

Category 2 — marginal

The ABS% is from 20–43%. The tint on these lenses is obvious and clearly marks them out as what most people would view as sunglasses. They’re ideal for overcast to moderately sunny days.

You can wear these when driving during the day but not the night.

Category 3 — dark

The ABS% is from 43–80%. The ideal sunglasses for playing outdoor sports or enjoying sunny days when the sky is clear use category 3 lenses. Category 3 sunglasses are the ones you’ll take on holiday, to the beach or for everyday use if you’re lucky enough to live where the sun is most often always shining brightly.

You can wear these when driving during the day but not the night.

Category 4 —very dark

The ABS% is from 80–92%. This means most visible sunlight is absorbed. Sunglasses with category 4 lenses are, therefore, not your everyday-use sunglasses. They are used for extreme sun exposure days, such as if you go mountaineering, and are very dark to peer through.

You can’t wear these when driving during the day or night.

Find your perfect sunglasses

Now you know which category of sunglasses works for which situations, you can buy your next pair of sunglasses with confidence.

And if you’re looking for the oversized appeal of big, bold sunglasses with protective category 2 or 3 tints, then take a look at our quirky Justine sunglasses. Available in over 30 different styles, there’s something for everyone looking to make a statement.