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
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 and premature ageing)
- 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?
That’s a common myth. Research shows that wearing sunscreen may slightly reduce vitamin D production, but it doesn’t block it.
The amount of UVB needed for vitamin D is far lower than the amount that causes sunburn, so you’ll still make enough while staying protected.
Regular, sensible time outdoors between March and September is usually all your body needs to maintain healthy vitamin D levels.
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.
