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How much sunscreen should you actually use?

How much sunscreen should you actually use?

You know you’re meant to wear sunscreen. But do you know how much?

Most people use less than half of what they need. And that’s a problem. Because when you under-apply, your SPF drops through the floor.

Here’s the science-backed truth about how much sunscreen to use — and how to finally get it right.

The gold standard: 2mg/cm²

Dermatologists and SPF testers all use the same baseline: 2 milligrams of sunscreen per square centimetre of skin.

In real-world terms, that means about 35 to 40ml to cover the average adult body — or:

  • A shot glass worth of sunscreen
  • Or 5ml (one teaspoon) per major body part:
    • Head/neck = 5ml
    • Each arm = 5ml
    • Front of torso = 5ml
    • Back of torso = 5ml
    • Each leg = 5ml

Tip: We include this 5ml per body part rule on our packaging. It's simple, easy to remember, and ensures full coverage.

Two fingers for your face and neck

This one’s easy:

  • Squeeze two full lines of sunscreen along your index and middle finger
  • That’s the right dose for your face and neck

Want more advice like this? Read How to protect your face every single day.

Why using the right dose matters

SPF protection isn’t linear. If you only apply half the amount you need, your SPF 50 might act more like SPF 7.

That means less protection against:

  • UVB (sunburn)
  • UVA (long-term damage)
  • DNA damage that leads to skin cancer

It’s also why we recommend reapplying every two hours — especially if you’re sweating, swimming or towel drying.

Cover these easy-to-miss areas

  • Ears
  • Back of your neck
  • Scalp (if exposed)
  • Tops of feet
  • Backs of hands
  • Lips — use our SPF 50+ Lip Protector

These are some of the most common spots for sun damage and skin cancer.

SPF 50+ only works if you apply enough

Here’s how to make sure your sunscreen does its job:

  • Use 5ml per body part
  • Reapply every 2 hours
  • Apply before going outside
  • Don’t forget your clothes count too — try our UPF 50+ protective clothing

Mineral vs. chemical? Use the same amount

Whether you’re using a mineral stick or a gel sunscreen, you still need 2mg per cm² to get the rated SPF.

Not sure which to pick? Read Mineral vs. Chemical Sunscreen: What’s the Difference?

Does sunscreen block vitamin D?

It’s a common myth, but good science says otherwise. Wearing sunscreen doesn’t block your ability to make vitamin D — especially if you’re spending time outside.

Even with high SPF, your skin still gets enough UVB to make vitamin D while avoiding burns.

Need a recap? Here's your cheat sheet:

  • 5ml per body part = proper full-body protection
  • Two fingers = face and neck
  • 35–40ml = a shot glass for the whole body
  • Reapply every 2 hours or after swimming/sweating
  • Cover your ears, neck, lips and hands
  • Pair sunscreen with UPF 50+ clothing for extra protection

The final word

You can have the best sunscreen in the world — but if you’re not using the right amount, it won’t work. Use more than you think. Apply often. Get every part. And don’t forget your lips, scalp and ears.