Tools · For guitar owners
Most humidity advice is a single number with no source behind it. This gives you two: the relative humidity your room will sit at month by month, and the moisture your wood will actually reach. It names the months where you are at risk.
A hygrometer reads relative humidity: how much water the air holds as a percentage of the most it could hold at that temperature. The words at that temperature are the whole difficulty. Warm air can hold far more water than cold air, so the same quantity of water reads as a high percentage when cold and a low one when warm.
This is why heating dries a room. Outdoor air at freezing and 80% RH, brought inside and warmed to 21°C, arrives at roughly 20% RH. Nothing was removed. The air simply became capable of holding much more, and the same water no longer fills it.
Your guitar does not respond to that percentage directly. It responds to moisture content: the water in the wood itself, as a percentage of its dry weight. A Spanish guitar was built around 8%. Below 6% the top shrinks against braces that are not shrinking with it, and that is when tops split.
This tool reports both, because one is what you can measure and the other is what actually matters.
1 · Where do you live
Used to look up published climate averages. Nothing is transmitted, and no location access is requested.
2 · How is the room heated
Forced air dries a room far faster than radiant heat. Heating cold air is what destroys humidity, not the cold itself.
3 · Where does the instrument sit
An exterior wall is colder, and colder means drier once the room is heated.
4 · In a case or out
A closed case holds its own microclimate and slows every change reaching the wood.
5 · About the instrument
Solid wood moves with moisture. Laminate mostly does not.
Optional · if you have a hygrometer
Enter the relative humidity your meter shows and the estimate is scaled to your actual room rather than your climate. Temperature is optional and only sharpens the moisture figure.
An estimate, not a measurement. Built from climate averages. Your room may differ; a hygrometer measures, this predicts.
Not advice about your instrument. It does not know its age, construction, or history. Damage can occur within these ranges, and instruments survive well outside them.
If you see a crack, a lifting bridge, or a change in action, see a luthier.
We hold nothing. Nothing you enter leaves your browser.
The ANICETO Collection is a private archive and does not provide conservation services.
Moisture values follow the equilibrium moisture content tables in Wood Handbook: Wood as an Engineering Material, FPL-GTR-282, USDA Forest Products Laboratory, 2021, a public domain federal publication, free to download chapter by chapter.
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