Key takeaways 

1. Check your intonation: tune each string in turn. Once it’s at the correct pitch, check the tuning at the 12th fret.  
2. Adjust the string: If your string is sharp at the 12th fret, the saddle is too far forward. If your string is flat at the 12th fret, the saddle is too far back.  
3. After adjusting a saddle, make sure to check the open tuning again before the 12th fret. 
4. Once each string is in tune when played open and at the 12th fret, you’re ready to go! 

What is guitar intonation? 

Guitar intonation is just a technical term for the accuracy of your tuning across the entire neck. Even if you’ve made sure everything is perfect when playing the open strings, once you start getting up to the dusty end of the fretboard, poor intonation means fretted notes can sound sharp or flat. 

You can test your guitar’s intonation by comparing the pitch of an open string to the same string fretted at the 12th fret. If the fretted note is noticeably out of tune, your intonation isn’t right. It’ll need adjusting to get your guitar sounding the way it should. This is easier than it sounds and involves fine-tuning the position of the individual saddles. 

Once you’ve got your intonation sorted, you’ll find chords and single notes will sound in tune no matter where you are on the neck, and you’ll be ready to get back to playing. 

It’s important to note that intonation isn’t a job you can do once and then forget; it’s something that naturally drifts over time for a whole range of reasons! Knowing how to check and adjust it can save you frustration and help keep your playing sounding the way it’s supposed to.

What affects guitar intonation? 

There are a lot of things that can affect your guitar’s intonation, but some of the most common are: 

1. Changing your strings – this can shift the saddles slightly, which may throw the intonation out. If you’ve restrung your guitar, stretched the new strings, and found that you’re out of tune at the 12th fret, it’s intonation time.
2. Switching to a different string gauge – this affects the tension across the neck and bridge. A change in tension can easily lead to an issue with intonation.
3. Temperature and humidity changes – the wood of your guitar expands and contracts with shifts in climate, and even small movements in the neck or bridge can impact tuning accuracy. If your guitar travels between different environments, it’s worth checking intonation regularly. Yes, this includes hot and sweaty gigs! 

There are many other things that can lead to the intonation being out, of course. These include issues with the action, uneven frets, an incorrectly cut nut, and more. If you think there’s something complex causing your problems, it may be time to contact an experienced guitar tech for some professional help. 

How to adjust your guitar’s intonation 

Before getting started, you’ll want to make sure that your guitar is on a flat and stable surface and protected from scratches. Our D’Addario restringing bundle includes an instrument care kit, complete with a non-slip body mat to keep things safe and steady as you work. 

1. Check your intonation

You have to find the problem to fix it! It’s often the case that not all strings will be affected, so you need to work out where the problem is. Get your tuner out and make sure the string you’re checking is in tune. Once it is, play it at the 12th fret – if it’s not in tune there, then there’s a problem with the intonation. Time to get it sorted… 

2. Adjust the saddle

If the 12th fret note is sharp compared to the open string, move the saddle back (away from the neck of the guitar) to increase the string length. If it’s flat, move the saddle forward to shorten it.

For most guitars, each saddle will have a screw that can be carefully adjusted with a suitable screwdriver, but it’s possible your guitar may use the same saddle for two strings – looking at you, Telecaster players! In this case, you have to make a compromise. Find a position that leaves both strings as close to perfectly intonated as possible. 

3. Keep checking as you work

Remember that small changes can make a big difference, so check the intonation regularly! Retune the open string, then check it at the 12th fret. Is it now in tune there? Is there a way to go still? Have you gone too far? If the intonation isn’t right yet, make another adjustment. You’ll soon get a feel for how far you need to turn the screw to get the adjustment you need. 

FAQs 

Is it possible to perfectly intonate a guitar? 

In practice, perfect intonation isn’t really possible. If your highly accurate electronic tuner is telling you there’s still a slight issue, turn it off for a moment and listen. The goal is to make it sound right – if it does, you’re there.   

Why can’t my guitar be intonated? 

If you’re finding that your guitar can’t be intonated, it may mean that there’s an underlying problem. This could be old or faulty strings, issues with the action that require a truss rod adjustment, or a range of other issues. If new strings don’t fix the problem, it may be best to consult a guitar tech. 

Should you loosen strings when adjusting intonation? 

Loosening your guitar’s strings can make intonation adjustments easier. While it’s possible to do the job without loosening the strings, the saddles will move more easily if you do. And, since you’re going to have to tune it every time you want to check the intonation, you might as well! 

Final thoughts

So, that’s it! Hopefully, our guide has shown you that getting to grips with intonating your guitar is a simple job that’s well worth your time.  

Guitar intonation is as simple as checking your tuning and turning a screw, and the difference it makes is huge. It’s also satisfying to know you can take care of it yourself, keeping your guitar sounding great and letting your playing shine, so why not give it a try?