What is Sun Protection Factor (SPF)

Sun Protection Factor (SPF): A designated number on a scale for rating sunscreens level of protection. SPF stands for Sun Protection Factor (SPF).

Sun Protection Factor (SPF) numbers on a package can range from as low as 2 to as high as 60. These numbers refer to the product's ability to screen or block out the sun's burning rays.

The Sun Protection Factor (SPF) rating is calculated by comparing the amount of time needed to produce a sunburn on protected skin to the amount of time needed to cause a sunburn on unprotected skin.

Let us take for instance a fair-skinned person who would normally turn red after 10 minutes in the sun. Ten minutes is their "initial burning time." If that person uses a sunscreen with SPF 2, it takes 20 minutes in the sun for that person's skin to turn red. Now, if that person uses a sunscreen with SPF 15, it multiplies the initial burning time by 15, so it takes 150 minutes, or 2 and half hours, for that person's skin to turn red. So you multiply your “initial burn time” with the Sun Protection Factor (SPF) number stated on the bottle of sunscreen.

Sunscreens with a Sun Protection Factor (SPF) of 15 or higher are generally thought to provide useful protection from the sun's harmful rays. The American Cancer Society recommends the minimum Sun Protection Factor (SPF) to be at least SPF-15.

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The Sun Protection Factor (SPF) of a sunscreen indicates the time period you can stay in the sun without burning based on your skins complexion. Below is a chart of the recommended time of exposure based on your skins complexion.

Recommended SPF

 

Skin Type

1 hr

2 hr

3 hr

4 hr

5+ hr

Very Fair /
Extremely Sensitive

30

30

45

50

50

Fair / Sensitive

15

15

30

30

45

Fair

15

15

15

30

30

Medium

8

8

15

15

30

Dark

4

8

8

15

15