Everything you need to know about that number on your SPF

21 July, 2023 / words by IALH Editorial Team

Written by IALH Editor

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I think most of us know the importance of SPF on your face and skin if you’re going to be outside in the sun (well at least I hope we do!). But what does the number after ‘SPF’ actually mean, should you go for a higher or lower one and how long does it protect you for once applied. We’re breaking down all the numbers and giving you the information you need to make safe choices for your skin.

What does SPF stand for?

It’s short for ‘sun protection factor’ and the number that follows (30 or 50 for example) indicates the more time you’re able to spend in the sun wearing that SPF against not wearing any at all.

You want an SPF that protects against both ultraviolet A and ultraviolet B rays simultaneously. Top tip – look for SPF that’s called ‘broad spectrum’ UV protection.

What do the numbers really mean?

The number tells you how much longer it will take to burn while out in the sun with that particular SPF on compared to if you weren’t wearing any at all. So wearing SPF 30, it would take you 30 times longer to burn than if you weren’t wearing any sunscreen. BEWARE – this is not an exact science, but here’s an example:

If it takes you 10 minutes to begin burning while out in the sun without any protection, applying an SPF 50 would mean you could spend approximately 8 hours in the sun without burning because 10 x 50 is 500 minutes. However we’d recommend definitely topping up your sunscreen in an 8 hour period if you were sitting in it for all that time or if your skin got wet.



IALH Editorial Team


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