This is the measure of how much sunscreen protects skin against UV rays. SPF acts as a multiplier and extends the time it will take for your skin to burn. So SPF 30 offers 30 times more protection ...

After years of beauty ... and an SPF of 30 or higher, and she notes that a high SPF doesn’t mean you can go hours without reapplying. You should always reapply sunscreen after every two hours ...