Having sun cream on during the usually hotter summer months is an important measure to help protect your skin, but some may wonder what the difference between all the types is.

These are usually signified by the factor number on the bottle, whether it be 15, 30 or 50.

All sun creams help to protect the skin by either reflecting or absorbing UV rays, so what difference does a Factor 50 make compared to a Factor 15?

Here's all you need to know about sun creams and their factor numbers.

What does the factor number on sun cream mean?

The number on sun cream bottles equates to Sun Protection Factor (SPF), which tells you how long it might take you to get sunburnt after applying it, versus not wearing any at all.

On the Nivea website, it says: "As an example: if you can spend 10 minutes in the sunlight without burning, a lotion with SPF10 will multiply this "self-protection time" by 10 to equal 100 minutes."

They add that this is just an approximation "since you might not be taking as long to burn depending on the season, the weather or even your geographic location."

Using this as a guide it means the higher the SPF number the longer you will be protected from sunburn after applying the sun cream to your skin.

The higher the SPF number the higher the percentage of UV rays it would block, as on Nivea's website it states SPF 15 blocks 93% of UV rays.

Recommended reading:

Meanwhile, SPF 30 blocks 96.7%, SPF 50 blocks 98% and SPF 100 blocks 99%.

They added: "UVB rays can never be totally filtered, which is why it is important to reapply SPF protection at least every 2 hours."

In most situations, SPF 30 is adequate protection, provided it is applied correctly, but SPF 50 is perhaps the safer option to prevent sun-induced damage.