SPF stands for sun protection factor and is a measure of how long a sunscreen will protect your skin from UVB rays that cause sunburn. A sunscreen with an SPF of 30, for example, means it takes 30 times longer for your skin to get burnt by the sun than when no sunscreen is applied. The higher the SPF, therefore, the longer the sunscreen will protect your skin from the sun.

Although SPF is a helpful measure to determine how well a sunscreen will protect your skin, it shouldn’t be the only factor one takes into account. Your skin type, age and how you apply the sunscreen can make a big difference in how well your skin is protected.