Short answer. Green noise is steady background noise with its energy focused in the middle of the sound spectrum, which makes it sound softer and more natural than white noise, a bit like steady rainfall or a distant waterfall. Unlike white noise and pink noise, green noise has no standard technical definition, so different apps can sell you different sounds under the same name. This page explains what the label means, what our version actually is, and where the research stands, which is a shorter section than you might expect.
Green noise definition: the honest version
Noise colors are nicknames for how a hiss spreads its energy across low, middle, and high frequencies. White noise spreads energy evenly across all of them, which is why it sounds bright and staticky. Pink noise tilts toward the lows, which sounds deeper and rounder. The colors are just labels for those shapes.
Green noise is the middle child. The name is used for noise weighted toward the middle frequencies, the range where a lot of everyday outdoor sound sits. That midrange focus is why people describe it as sounding like rain, rivers, or wind through leaves.
Here is the part most pages skip. White noise and pink noise have precise engineering definitions, so white noise from one app is shaped the same way as white noise from another. Green noise does not have an agreed standard. It is a consumer label, not a measurement. Two apps can both say green noise and play noticeably different sounds, and neither one is wrong, because there is no rulebook to be wrong against.
So we can only define our own version exactly. On this site, green noise is white noise filtered so its energy peaks around 500 Hz, in the middle of the spectrum, with the highs and lows rolled off. That is not a claim about what green noise must be. It is a statement of what our generator plays, and the player on this page lets you hear it.
What does green noise sound like?
Compared with white noise, green noise sounds less like static and more like weather. The harsh, hissy top end is pulled back, and the deep rumble is pulled back too, leaving a steady wash in the middle. Many people find it rounder and easier to sit with for a long stretch. If white noise reminds you of a detuned radio, green noise is closer to steady rain on a roof without the drops.
Whether that is pleasant is personal. Some people love the naturalness. Others find the midrange focus makes it feel closer and more present than they want from background sound. The only reliable way to know is to listen for a minute, which costs nothing.
How green noise compares to white, pink, and brown noise
The one-line versions: white is even everywhere and sounds the brightest. Pink tilts toward the lows and sounds balanced and rounded. Brown tilts hardest toward the lows and sounds like deep rumble. Green sits in the middle band, and is the only one of the four without a standard definition.
If you want the full comparison of the noise colors and how they differ, our colored noise guide covers the whole family in one place, and the white noise and pink noise pages go deep on the two most studied colors.
Where the research on green noise stands
Briefly: the noise and sleep research you may have seen was mostly done with white noise and pink noise. None of the studies cited across this site's guides tested green noise specifically. We are not going to borrow findings from one sound and pin them on a different sound, so this page makes no research claims about green noise at all.
That does not make green noise useless. Steady sound covers up sudden noises, and it works best on sounds that sit in the same part of the spectrum it does. Green noise is focused in the middle, so it does more for midrange sounds than for a deep rumble or a high hiss. The thin research does mean that anyone quoting studies at you about green noise specifically is probably stretching. If you are choosing a noise color for sleep, our green noise for sleep page covers that decision, and the honest answer everywhere on this site is the same: pick the color you find most comfortable, because comfort is the thing that keeps a sound on all night.
Keep the volume modest, low enough that you could still hear someone speaking to you. A louder sound does mask more, so there is a real trade here. Hours of loud audio are hard on your hearing whatever the sound is, which is why we point you at the quiet side of that trade.
Try it
Give it sixty seconds with the player on this page. If you want to hear how the other colors differ, our colored noise guide covers the whole family.