Neon Green (#39FF14) is a very light, highly saturated green hue. Neon green is a glowing, high-visibility green used in safety gear and gaming brands.
In RGB it is made of 57 red, 255 green and 20 blue. Its HSL hue angle is 111° with 100% saturation and 54% lightness, while its perceptual OKLCH lightness is 87% with a chroma of 0.286. For print, a starting CMYK mix is 78% cyan, 0% magenta, 92% yellow and 0% black.
As a text color on white, Neon Green has a contrast ratio of 1.36:1, which fails WCAG AA even for large text. On black it reaches 15.49:1 and passes AA for normal text. If you use Neon Green as a background, put black (or very dark) text on it. The APCA lightness contrast is Lc 87 for black text and Lc -19 for white text.
Its perceptual complement is #F6BEFF, close to mauve. Colors that look most similar are chartreuse, mint, lime green. People with red-green color blindness see neon green quite differently (ΔE 20), so do not rely on it alone to signal meaning.