What is the difference between SPF 30 and SPF 50?
The SPF of a sunscreen is derived by taking the time it takes you to burn with a sunscreen and dividing it by the time taken for you to burn without a sunscreen. For example if you burn in 300 minutes with a sunscreen and 10 minutes without a sunscreen, this is 300/10 = 30. So the sunscreen will have an SPF of 30.
If you put it on correctly and reapply as recommended, an SPF 50 sunscreen will offer 50 times your natural protection. An SPF of 50+ will reduce the damaging UV rays getting to your skin by about 50% when compared with to an SPF 30+* if used correctly. Reducing the UV light getting to our skin by 50% means that we are reducing our risk of getting sun burnt or precancerous skin changes. It’s a great move for Australia given our harsh UV conditions.
*SPF 30+ is defined as SPF 31, and SPF 50+ is defined as 60.1 as per AS/NZS 2604: 1998 & 2012