Guitar Action: The Complete Guide to String Height & Action Adjustments

Guitar Action: The Complete Guide

When it comes to instruments—especially stringed instruments—one of the most important considerations for the musician is how the instrument plays. In technical parlance, this is commonly referred to as an instrument’s action. Today, we’ll be talking all about guitar action—what action is, how to know the right string height for your instrument, and the three ways to adjust the action on your guitar.

For the piano and other keyboard-based instruments, action simply refers to the feel of the keys under the fingers. For guitar players, the term action can similarly be used to describe the general feel of the instrument when played, but it also has a much more precise definition—the height of the individual strings.

As we’ll talk about below, string height plays a critical role not just in the feel of the guitar strings but also in the way that the guitar actually sounds. Finding the right action for you and your instrument is the key to getting your guitar or bass sounding, playing, and feeling the way you want.

A guitar’s action does more than just determine how it plays

Guitar Action at the 12th fret of a Fender Stratocaster
Guitar Action at the 12th fret of a Fender Stratocaster

A guitar’s action is defined principally in terms of the height at which the strings sit above a given fret. Experts differ in their opinions about which fret is best to measure string height from, with most saying that measuring from between the 8th and the 12th fret, is the best. At Stringjoy, we tend to look at the action at the 12th fret, but if you’re more comfortable using a different reference point, that’s fine too.

So if action has a more broad definition when referring to other instruments, why is a guitar’s action defined in terms of the height that the strings rest above the fretboard? Well, because this is one of the most principal factors in defining both how the guitar feels and how it sounds. Particularly high-set strings are generally considered by players to be cumbersome and uncomfortable to deal with. On the other hand, setting strings too low results in the dreaded “fret buzz,” where the strings vibrate against unplayed frets, resulting in the typical buzzy sound that so many older or poorly maintained guitars are known for.

The height at which the strings sit above the fingerboard is also a critical factor in how aggressively the guitar can be played. Higher string settings will allow for more forceful strumming while maintaining a high degree of clarity and crispness of the notes, while lower settings will tend to quickly generate severe fret buzz when fortissimo passages are called for.

As with almost everything else guitar related, there are significant differences between how the action on electric and acoustic guitars should be set. Here, we’ll take a look at some of the considerations you should keep in mind when setting the action on your guitar and how best to go about it.

Why is guitar action lower on electrics?

Action at the Bridge of a Fender Stratocaster

The height at which the strings sit above the fingerboard is a critical factor in how aggressively the guitar can be played.

There are significant differences between the way that most acoustic and electric guitars are played. Generally speaking, electric guitars require a less-forceful approach (though depending on the player, this may or may not be the case). Thanks to the invention of the magnetic pickup, a player is able to transmit virtually unlimited sound to an audience with a minimum of physical exertion upon the strings themselves. This is also how so many players can make downright massive sounds with super light guitar strings.

Another consideration with electric guitars is that the amount of perceived fret buzz when the instrument is not plugged into an amplifier can be significant compared to what you will hear under amplification.

Because of all these factors, electric guitar action can be set far lower than that on acoustic guitars, typically anywhere from .15″ to .05″ lower, on average.

How to choose your string height

Guitar Action at the 12th Fret of an Epiphone 339
Guitar Action at the 12th Fret of an Epiphone 339 Electric

In order to measure the height of your guitar’s strings, you should have either a ruler, a feeler gauge, or a specialized string action gauge.

For electric guitar action, in our opinion, a good default string height at the 12th fret is typically about 6/64th of an inch (2.38mm) on the bass side and 4/64th of an inch (1.59mm) on the treble side.

For acoustic guitars, we’ll want to go just a bit higher than this:

For acoustic guitars, our recommendation bumps up to 7/64th of an inch (2.78mm) on the bass side and 5/64th of an inch (1.98mm) on the treble side.

These are just rules of thumb, of course. There is a considerable amount of leeway in choosing the right action height, depending on your instrument and playing style. Those who play their guitar strings more forcefully or aggressively may want to raise their strings by a 64th or two whereas those who are able to get away with much lower string heights without producing unwanted fret buzz may find that the lower settings are more comfortable for them.

3 ways to adjust your guitar’s action

There are two main ways that the action on a guitar is typically adjusted. These are the adjustment of the truss rod and the bridge saddles. A third contributing factor is the guitar’s nut, which plays a slightly less prominent role in the height of the strings. On electric guitars, none of these means of string-height adjustment are beyond the capabilities of a dedicated do-it-yourselfer who possesses just a couple of tools.

1. Adjusting the truss rod

Adjusting Action using the Truss Rod
The Truss Rod access point on a Fender Stratocaster

Most guitars have incorporated truss rods since at least the middle of the 20th century. These are metal rods that run through the neck of the guitar and attach to the body. The truss rod can be loosened or tightened, usually with a simple Allen wrench (if you purchased your guitar new it’s likely that it come with one in the case).

The mechanism by which the truss rod affects the string height above the fingerboard is quite simple: loosening the truss rod allows the strings to exert more force, causing a forward-bowing effect, while tightening the truss rod counteracts the strings’ tension, straightening the neck (and of course if over-tightened the truss rod can also cause back-bend in the neck).

Ideally, the truss rod should be tight enough so that the neck of the guitar is ever so slightly bowed concavely. In practical terms, it should appear as if the neck is effectively straight.

As seasons change, so do guitars. It’s not uncommon to wake up one day in the spring or fall and find that your guitar has either too high of action or is buzzing due to lower action. When this is the case, a simple truss-rod adjustment (often no more than a quarter turn either way) is all that’s required to get everything back into perfect playing shape.

2. Adjusting the bridge or saddle height

Adjusting Guitar Action at the Bridge
A Tune-O-Matic, or “Gibson-style” bridge (here pictured on an Epiphone)

The saddle height is the other important factor in determining action height. Depending on the guitar, it can be incredibly easy to adjust, or a royal P.I.T.A…

Broadly speaking, electric guitars tend to either have a “Fender-style” or a “Gibson-style” bridge/saddle system. Fender saddles allow the height of each string to be adjusted individually. This gives the player a great deal of control, but it also means that you will have to pay special attention to maintaining the correct radius so that the action is even across each string. A Gibson-style (Tune-O-Matic) bridge only allows for adjusting either the whole treble side or the whole bass side, which gives you less control, but also makes basic adjustments a bit easier to perform.

Adjusting Guitar Action on a Fender-Style Bridge
A common “Fender-style” bridge on a Stratocaster

On electric guitars, adjusting the saddle height is usually a simple matter of carefully measuring the height and then using a screwdriver or allen wrench (depending on the bridge) to raise the strings appropriately.

Unfortunately, acoustic guitars present a far more challenging situation. In order to raise or lower the saddle on an acoustic guitar, it is necessary to remove the strings, take out the saddle and then either sand it or glue on a shim.

Raising or lowering the saddle on acoustic guitars requires careful, precision craftsmanship and, while many players may be able to complete this job themselves, taking your guitar into a shop and having a professional handle the saddle height adjustment will almost always be worth the usually nominal cost, especially where high-end vintage guitars are concerned.

3. Adjusting nut height

Adjusting Guitar Action at the Nut
An after-market bone nut, cut for our Balanced Light (10-48) Electric strings

The factors that cause guitar action to shift over time (wear and tear, saddle height shifting, expansion and contraction of wood) tend not to have as substantial of effects on the nut than they do on the bridge or neck. So typically when it comes to regular action adjustments, players can leave the nut as-is.

That said, nuts can wear out over longer periods of time, and this will eventually affect your action after many years. If neither of the above techniques get your action where you want it and it seems like a replacement nut may be required, you can get one that comes pre-cut for not much money, or you can cut one yourself for your preferred gauge of strings.

Go with the guitar action that works for you…

Finding the right action for you and your instrument is the key to getting your guitar or bass sounding, playing, and feeling the way you want.

Because every guitar player has their own unique style, and players’ use profiles differ considerably from one to the other, there are no hard and fast rules about string height, just some general rules of thumb. As with all things guitar, what makes your guitar play the way you want it to is the only thing that matters.

And don’t forget, if you’re picking up a new set of acoustic guitar strings (or electric), ones that are a different gauge than you’re used to, you’ll want to consider adjusting the action.

27 Responses

  1. There are several ways to adjust the neck and or playability. They are different yet can be the same. It depends what and how you play and how much bow is in your neck. The T rod is there to take the bow out of the neck not necessarily for adjusting string height. That varies with humidity and temperature. I play an electric acoustic that is very sensitive to both. I suggest you take it to a pro before trying to adjust it yourself. you might save money and an instrument.

  2. So for a new nut or a brand new guitar … what is the nut slot depth and sting height when using the ‘3rd fret test’ ? You did not explain that or even specify what to do and why at the nut slots… basic stuff for comfort and you skipped all of it.

  3. for what it’s worth–if you have an “up-bow ” condition , you need to take some relief out by loosening the tr. you don’t need to loosen the strings to do this because you are not increasing string tension. on the other hand, if you have too much relief and need to tighten the truss rod , it only makes sense to loosen all the strings so you’re not putting too much strain on the truss rod . an average of between 120-150 lbs of string pull will be placed on the truss rod if you don’t loosen all the strings and possibly snap the truss rod

  4. After doing all of you’re adjustments you will always check again the truss rod.the string tension has a pull on the head of the neck which may increase the relief in the neck.Thanks.

  5. This is a bad article/post. Pico said it best. You set the TR first, without strings on. Or at least zero tension. You tighten the TR enough to give an very slight concave-ity. Then string it, tune it (more or less) and check the action. If adjustment is needed, remove all tension from strings and adjust the bridge. On an LP you have a couple different ways of adjusting height on the bridge. Should’ve gone thru all that. I won’t here.

    1. Sorry you feel that way Travis, but your preferred way of setting the truss rod is not the same as ours. I don’t know if that makes either “bad”, but you’re entitled to your own opinion.

    2. Hi Travis, people work differently and get to the same goal. I generally don’t criticize unless I can suggest an alternative.

      I generally don’t loosen all my strings to adjust the truss rod. I’m mostly concerned with having the right amount of bow in the neck. Some people don’t want any. If it’s slightly sticky, I’ll apply pressure to the neck to relax the strain on the TR and then turn it. If I’m tightening it, I’ll be extra careful not to force, in case it’s at the max, already. Forcing too far can be seriously counterproductive! LOL!!!

  6. As someone that grew up in the US and also knows the metric system, I would love to hear what systems you’re familiar with that would lead you to think the US system is best. If there’s something WORSE than the US system, I would love to see it!

    1. The binary system used in computers, which then uses bits, eight bits make a byte then a hexadecimal system is used to build the computer system from there. Notice it follows the sae standard, not metric. Metric, though ballyhooed by Europeans, the history of its use is just as arbitrary. One big glaring example is a mile or mil, a thousand steps, the kilometre, also was originally a thousand steps. Apparently one was with shorter legs.

      Knowing both and how hey work is good, but tools and the like makes teaching fractions much simpler. IMO.

  7. Neck Relief (set with the truss rod) depends on the fret board radius and how hard you play. Fender recommends .010 inches on 9.5 – 10 in radius Stratocasters (use a calculator if you prefer mm, 1 in =25.4mm). Fender also checks action at the 17th fret – maybe to minimize the effects of truss rod adjustment/neck relief on action measurements.

  8. Ok, nice article but not many places on earth uses inches. It would be nice to have a mm in parenthesis. Thanks anyway!

    1. Just added some MM conversions into the article for ya! Appreciate the suggestion, we’re an American company and sell mostly to American customers so it’s easy to forget things like this. Glad to be able to be a resource for folks all over the globe!

    2. We do here in the United States, and it’s a wonderful system of measurement – I would argue the best. Besides, I bet the majority of Stringjoy visitors (of any single country on the planet) are from the United States…because it’s an American company. So there you have it. Great article, Stringjoy Staff! And thanks for going the extra mile on this one. 😉

  9. Adjusting the truss-rod is not a way to adjust strings action. Truss-rod is used to keep the guitar neck straight. Changes in truss-rod tension has as a consequence a change in strings action, but it is not intended as a way to adjust it. Once you have straightened the neck as it should be with the TR, then you adjust strings action raising or lowering strings saddles ot the bridge, depending on what your guitar has.

    1. So, assuming your guitar is set up correctly, sure. However, many guitarists look at truss rod issues and see them as action issues (since the string height at one position on the neck is too high) and come here, which is why we wanted to make sure to include some wisdom on that front in the post.

  10. Changing the nut is cheap and easy to do. I didn’t even know what action was last week, and I just changed a pre-slotted nut in a Strat copy. Wrong nut too, but that just required some sanding. Not hard at all and I’m a super novice.

  11. Fabricating a nut takes practice and gauged tools to come out with properly functional and esthetically professional project, and premade nuts almost never fit right. With some simple math, adjusting saddle hight on acoustic instruments are considerably easier.

  12. Do you no what tool you use to adjust string height on 1987 mij ventage 57 reissue tremillo bridge. Thank you.

  13. I tried to leave a sensible reply, regarding the lack of information about Truss Rod adjustments, but this was not allowed, because I had made the comments before, which is total nonsense.

  14. Adjusting the Truss Rod…….no further information on “settings”? Where and how to set it up, with the “normal” parameters outlined?
    OK, so I know these facts. BUT only because they’ve been passed on by others.

  15. I really like the compound neck shape and fretboard radius on my 2017 Fender American Elite Stratocaster. The back of the neck begins with a C at the first fret, and gradually changes to a D, at the guitar/neck joint. The compound fretboard radius begins with a 9 1/2″ radius at the first fret, and gradually changes to a 14″ radius at the guitar/neck joint. It’s probably the most comfortable neck I’ve ever played.

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