SPF, What Does It Really Mean?

So, you have been wondering what SPF really means? Well, it simply represents the Sun Protection Factor. It signifies the duration of time you could spend in the sun without getting burned compare to someone without it for instance.

How Is SPF Calculated?
SPF manufacturers determine the number using an indoor experiment where the skin is exposed to a light spectrum analogous to the sun. The time it takes for the skin of subjects without the SPF to burn compared with the time it takes the subjects who applied the SPF is used to calculate the SPF Number. To calculate your own:

  1. Take the time you would normally burn in the sun without protection, 20 minutes will normally produce redness on a light-skinned individual.
  2. Multiply this number by the SPF of your product. Example: with an SPF 15 x 20 minutes of sun time = 300 … is how many minutes you can stay in the sun without burning.

Let’s look at it this way. The average time it will take someone without any protective measure to get burn in the sun is say 20 minutes. If you apply an SPF 30, you can stay longer in the sun for about 3 hours.

How To Effectively Use The Sun Protection Factor

It is not entirely true that the higher the number of the SPF you use, the more protective you become. No sunscreen blocks out the sun 100% protection. Sun Protection Factor 15 blocks about 93% of UVB, SPF30 blocks 97% and SPF50 blocks 98%. In reality, the sun rays differ from one location to another, factors like; distance from the equator, altitude and time of year also play a part in the strength of the sun rays. For efficient protection from the Sun Protection Factor, always reapply at most every two hours and immediately after swimming or sweating irrespective of your SPF number.

SPF Supplementary Protective Measures

When it was developed, the designers only had sunlight UVB rays in mind. But later, it was discovered that UVA rays too pose threats ― they age the skin and may initiate cancer. That is why you may need additional protective measures when exposed to sunlight. Consider using sunscreen or sunblock and SPF clothing which protects against UVA and UVB. When purchasing your sunscreen or sunblock, ensure they are tagged broad or full spectrum.