font size

Definition of SPF

SPF (sun protection factor): A number on a scale for rating the degree of protection provided by sunscreens. SPF stands for Sun Protection Factor.

SPF numbers on a package can range from as low as 2 to as high as 100. These numbers refer to the product's ability to screen or block out the sun's burning rays. It is a common mistake to assume that the duration of effectiveness of a sunscreen can be calculated simply by multiplying the SPF by the length of time it takes for him or her to suffer a burn without sunscreen, because the amount of sun exposure a person receives is dependent upon more than just the length of time spent in the sun. The amount of sun exposure depends upon a number of factors including the length of exposure, time of day, geographic location, and weather conditions.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=6333
Last Editorial Review: 8/28/2013

Drug Medical Dictionary of Terms by Letter

Top RxList Drug News

Women's Health

Find out what women really need.

Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations