The SPF indicated the length of time that you skin is protected from sunburn. All skin types are different and have varying results from sun exposure. The SPF number is only a guide to it’s level of protection
Depending on you skin type, location and the time of year, the time it takes for you to begin getting burned is between 5 to 30 minutes on average.
To help you understand a bit better if you start getting sunburned after five minutes in the sun without any sunscreen applying a sunscreen with an SPF30 would protect you for 30 x five minutes (or 150 minutes) before you begin to burn
There are some other factors that will also affect your level of protection, such as:
- How much sunscreen you apply
- The weather conditions
- If you are wearing protective clothing, a hat, sunglasses
- How much you sweat
- How long you swim and how well you dry off afterwards
- Your skin type