SPF, or Sun Protection Factor, increases the length of time you can stay outside in the sun without incurring sunburn or irritation from UV-B rays. At present there is no standard to measure protection from UV-A rays.
Calculate your recommended SPF:
- Rate yourself:
Select your skin type. The corresponding amount of time indicates how long you can stay safely in the sun before burning.
Fair skin - 10 minutes
Olive skin - 15 minutes
Dark skin - 20 minutes
- Look at the SPF on your sunscreen
Note which SPF is stated on the product labeling, eg. SPF 20
- Calculate your protection time, the amount of time you can stay outside before burning:
Multiply the sun safety time for your skin type with the SPF listed on your sunscreen.
eg. 15 minutes (for olive skin) x SPF 20 = 300 minutes (5 hours) of sun protection
Result: Olive skin using a sunscreen with SPF 20 can under ideal conditions stay in the sun for up to 5 hours.