What's the ideal humidity for storing a guitar?

40 to 60 percent relative humidity, with 45 to 50 percent being the sweet spot most guitars are actually built and voiced around. This isn't an arbitrary range — it's roughly the humidity level most instrument wood is stabilized at during manufacturing, which is why straying too far from it in either direction causes problems.

Why the range exists

Wood expands when it absorbs moisture and contracts when it releases it. Guitars are built with wood that's been dried and stabilized to a specific moisture content, and the whole structure — top, bracing, neck joint, finish — is essentially calibrated to that baseline. Push humidity too low and wood shrinks, risking cracks, fret sprout, and finish checking. Push it too high and wood swells, risking bellying, high action, softened glue joints, and a generally sluggish, muted tone.

Why the target matters more for acoustics

Acoustic guitars have thin, largely unsupported tops doing double duty as both structural and acoustic components, which makes them more sensitive to humidity swings than solid-body electrics. Electrics aren't immune to humidity effects entirely, but the stakes are generally lower without a thin, vibrating top and internal bracing in the mix.

How to actually maintain it

A hygrometer — an actual one, not a guess based on how the air "feels" — is non-negotiable if you're serious about this. Case humidifiers work well for guitars stored in cases; room humidifiers or dehumidifiers work better if the guitar lives out on a stand in a space you can control more broadly. Whichever method, the goal is the same: keep the guitar in that 40 to 60 percent range as consistently as the season allows, rather than reacting only after damage shows up.

The bottom line

This is one of the few pieces of guitar maintenance advice that's genuinely simple, cheap, and has an outsized impact on long-term structural and finish health. If you do nothing else, do this.