Sunscreen – SPF 50+ vs 30+: What’s the difference?

Sunscreen is a critical element in protection from the sun’s skin cancer-causing ultraviolet radiation (UV), however many people are putting themselves at risk by not applying sunscreen correctly, according to Cancer Council.


They say part of the cause is that the Sun Protection Factor (SPF) rating system is often misunderstood, particularly the benefit of SPF 50+ over SPF 30+ and how sunscreen protects the skin.

Sunscreen works by filtering out the sun’s harmful ultraviolet radiation (UV) which reach earth in two forms: UVA, which has long been known to cause aging and wrinkles and more recently proven to contribute to skin cancer risk, and UVB, which is the main cause of sunburn, skin damage and associated deadly skin cancers. Cancer Council recommends that when choosing a sunscreen it should be at least 30+, water resistant and labelled as “broad spectrum” meaning it protects against both UVA and UVB radiation.

SPF 30+ sunscreen filters out 96.7 per cent of UVB radiation while SPF 50+ sunscreen filters out 98 per cent. Despite the 30-50 labelling hinting at a significant increase in protection, SPF 50+ filters only an extra 1.3 per cent of UVB rays, which Cancer Council says can give people a false sense of security and lead them to apply less sunscreen or not apply it as often.

Guidelines call for both SPF30+ and SPF 50+ sunscreen to be applied every two hours (regardless of what the packaging says) or after swimming, sweating or towel drying. While some sunscreens may provide resistance to water and sweat they are not waterproof and can also be rubbed off.

Usage recommendations call for approximately 35ml to be used on an average size adult – or one teaspoon per limb, face and front and back of the body. This liberal and regular application of sunscreen in combination with other sun protection measures such as broad-brimmed hats, protective clothing, sunglasses and shade is essential to minimise your risk of deadly skin cancer.