SPF = Sun Protection Factor

Have you ever wondered what the SPF rating means?

The SPF rating tells you how long you can stay in the sun without burning from UVB (burning) light. It's like a sunburn meter. SPF is a measure of a sunscreen's ability to prevent UVB from damaging the skin.

Here's how it works:

If it takes 20 minutes for your unprotected skin to start turning red, using an SPF 15 sunscreen theoretically prevents reddening 15 times longer — about five hours.

The equation:

with an SPF 15 x 20 minutes of sun time = 300 … is how many minutes you can stay in the sun without burning. 300 minutes divided by 1 hour of 60 minutes = 5 hours of sun protection without a sunburn.

Don't forget to re-apply every 2 hours, or apply immediately if you've been perspiring or after swimming.