How to Adjust Acoustic Guitar Action

acoustic guitar action

Do you remember the first time you picked up an acoustic guitar? If it was anything like mine, your fingers bled from the extremely tough tension in the steel strings. On one hand, this excruciating experience helped me build callouses that eventually made guitar playing easier. On the other hand, if I’d known any better, this pain could have been avoided by lowering the action on the guitar.

Adjusting the action on an acoustic guitar is an easy maintenance task that anyone can learn to do. In this article, I will describe how high/low action affects your playing experience and walk you through how to adjust your acoustic guitar’s action to your preference.

What is guitar action and why is it important?

The action of your guitar is essentially the space between the strings and the fretboard. If that space is too large (high action), the strings will be harder to push down and it will likely be more painful to play. High action makes it more likely that you will touch unwanted strings when playing the guitar as well. If that space is too small (low action), the guitar may make buzzing sounds when you strum or pluck.

It is ultimately up to you as the guitarist to decide how you want your action to be set up. For example, while high action generally has a clearer sound, it can be difficult to play fast licks and arpeggios unless you have strong calloused fingers. Low action may not be a problem for guitarists who play lightly. But if you are rocking out and playing heavy chords, there will likely be some buzzing as the string makes contact with the frets.

How to tell if an acoustic guitar needs the action adjusted

Although the guitar’s action is generally a personal preference of the guitarist, there are certain scenarios where it is necessary to adjust the action of an acoustic guitar.

Constant buzzing

If the strings buzz when you strum or pluck, the action is likely too low and needs to be adjusted.

Unable to press the string down all the way

If the strings are very hard to press down, you may not be able to even press down on the frets. If this is the case, you should lower the action as it is too high.

Neck is warped

Visually check your guitar’s neck. If you notice that the neck is warped in any direction, you will need to adjust the action or the truss rod. It is fairly easy to fix a neck that is bending slightly forward or backward. But if the neck is twisted slightly to the left or right, I would recommend taking the guitar to a luthier or guitar technician, as this is a much more difficult issue to fix.

The intonation is off

Intonation is important, especially for more advanced guitarists that play higher on the neck. A warped neck or out-of-balance action can affect the intonation of your acoustic guitar, making it unable to play in tune with itself as you play notes higher on the neck.

How to adjust the action on an acoustic guitar

There are a few different parts of your acoustic guitar to work on when adjusting the action. Here is a step-by-step guide for how to adjust the action.

Step one: check if the neck is straight

The first step is to visually check the neck to see if it is warped in any direction. Sometimes, the warp can be very slight. A warped neck can be caused by high action or other factors such as weather and time.

For a more accurate test, place a ruler on top of the frets and make sure that it sits straight on both the first and last fret. If the ruler seesaws between the frets, it is likely bowed.

If the neck is twisted to the left or right, I recommend taking the guitar to a professional.

Step two: adjust the truss rod if necessary

It may seem like a scary task to tighten or loosen the truss rod, but trust me, it is more difficult than you think to break one. If you are attempting to adjust a front bowed neck, you should tighten the truss rod. If you are trying to adjust a back bowed neck, you should loosen the truss rod.

Step three: adjust the saddle

The next step to adjusting the action of your acoustic guitar is to adjust the saddle. This can be quite a pain to do as you will either need to file down the material of the saddle or purchase a new one.

If you plan to raise the action, you will need to purchase a slightly larger saddle and then file it down to the size that works best. Another DIY option is to super glue a small piece of material underneath the saddle to raise it. This can be a piece of cardstock, cardboard, or a thin piece of plastic.

If you plan to lower your action, you will need to file down the saddle until it is as low as necessary. I recommend taking it slow and checking the saddle after filing just a little bit. If you over-file the saddle, you risk having to purchase a new one!

Step four: adjust the nut

I would not recommend messing with the nut unless absolutely necessary. This is the most tedious way to adjust the action. Similar to the saddle, you want to add material under the nut to raise it and file it down to lower it. If you plan to adjust the nut, be VERY careful to not over-file, as the nut is a much more sensitive area to adjust.

Other factors that can affect the action of an acoustic guitar

There are other factors than can affect the action of your acoustic guitar other than the physical make-up of the instrument.

String gauge

Thicker gauged strings mean less space between the string and the fret, which can lower the action. It is common for guitar players to assume they need to adjust their saddle when in reality, the new strings they are using are just changing the action.

Different tunings

Everyone loves tuning in to Drop D and jamming out. But constantly changing the tuning of your acoustic guitar will change the tension of the strings against the neck and eventually mess with the action.

Ideal action for an acoustic guitar

The ideal action for an acoustic guitar really differs depending on the guitar and the preference of the guitar player. Typically, the action of an acoustic guitar’s low E string is around 2.5-3mm and for the high E, it is 2-2.5mm.