Start by looking at the inside part of your arm. This area is naturally hidden from the sun and, therefore, not sun damaged or discolored, which is why skin in this area best to reveals how warm, cool, or neutral your skin really is.
Answering the following questions is also helpful:
Does your skin tan easily and rarely sunburn? If so, you probably lean toward a warm or neutral undertone. If not, there’s a good chance you fall into the cool-toned category.
Do your veins appear bluish or more deep purple? If the answer is yes, you’re likely in the cool-toned spectrum. If your veins appear greenish, you most likely skew toward the warm-toned. Those with neutral undertones will have difficulty discerning either color—it will just all look neutral.
Do you look better in silver or gold? Personal preferences aside, cool undertones tend to be flattered by silver/platinum; those with warm undertones look better in gold-toned jewelry. Neutral skin tones look equally great in both.
Does your skin look somewhat ashen or gray? You might have the wild card of the bunch—olive skin—which is a combination of the natural neutral, slightly yellow undertone everyone has plus the greenish ashen hue that’s unique to olive skin. Olive skin tone is very specific, but is not neutral, as some tend to call it.