Nut calculator

If you find this utility useful, please link your site to this page.

This calculator is for use with 6-string guitars. It accurately calculates the position
of the nut slots for even-spaced strings using any combination of string gauges. It has two modes of operation:

  1. You can specify the size of gaps you require either side of the e-strings, or
  2. what overall string spacing, E-e (in mm) you require.

It then calculates the required distance for each string from both the bass and treble edges of the nut.

Simply enter the nut width in millimetres and either the end-gaps or the overall string spacing (again in millimetres)
and the gauge of each string in thousandths of an inch (i.e. 46, 36, 26, 17, 13, 10 or whatever.)

Press the calculate button for an instant result.

End gaps (mm):
  Distance from nut edge (mm)
String Diameter (thou) Diameter (mm) Bass Side Treble Side

42 Comments on “Nut calculator”

  1. I wonder why, on a production guitar, why you would not start with the spacing at the bridge and carry that down to the nut. It can be done precisely with photography and digital scaling. Puzzeled in the Okanogan.

  2. Hello and thank you for this gift to the guitar community. I want to install a new bridge on an electric archtop. Could this calculator be useful if I have to E and e strings spaced where I want them?

    I would think so.

    • Yes absolutely it would, but propotional spacing makes less of a difference when the strings are more widely spaced.

      • Excellent Steve thank you for the response. Tricky one as it is on short scale Gibson Byrdland. Fairly narrow and I feel the string spacing at the bridge could be a bit better.

      • I also need to find a suitable ebony or rosewood base. Gibson could not provide a replacement. Would like to put the posts into the bridge myself to ensure the proper spacing (bridge fit). So two space items going on.

  3. There seems to be a lot of requests for specific calculators for 4, 5 stringed instruments etc.
    My guess is that the easiest way to accommodate all these variations would be to adjust the calculation equation to take into account the amount of strings required and have an extra box in which to enter that amount rather than having separate calculators.

    • Hey Steve you think a 12 string spacing would be possible or possibly for a 10 string cittern? BTW thank you so much for this!!!! Love from Canada

  4. Great stuff and well designed. Thanks very much for your effort and time in developing this app, much appreciated by everyone I am sure :-)

  5. Thank you very much for this tool! I’ve just discovered it and am using for a Strat-like guitar.
    Thanks a lot, really!

  6. Thank you. Just what I was looking for.
    I think this may be a silly question …but is the distance given from the bass and treble ends to the center of the string or the closest edge of the string?
    It makes a fair difference on lower strings.
    Thank you.

  7. Thank you for clarifying. But when the calculator gives a value for the distance from the edge of the nut to, for instance, the D string, do I mark off that distance and then file the slot for the D string at that point, using it as the center of the string? I think this must be right, and the calculator then makes sure that the distance between all strings is the same. Is that correct?

    Thanks again for the help!

    Don in Vermont

  8. I like this useful tool. It is unclear though whether the distances from the nut edge which it provides are to the center or to the near edge of each string.


  9. Just found this today.
    What a useful tool for an amateur repairer like me.
    Your generosity in providing your skilled work free for public is something we all need to cherish.
    I thank you.

  10. Good morning Steve,

    I get a good impression from this: from your skill and generosity to design and provide free of charge a clever and precise tool like this calculator — also, from your intelligent and good-natured responses to comments and questions.

    I’ve clicked the box for email notifications, and I’ll be looking into your site some more to glean bits of wisdom from your experience, which I’m guessing is pretty long and varied.

    Thanks very much,


  11. Well done Steve, this is a brilliant free online tool. I for one appreciate your making this available to use.

  12. I would like to thank Steve for producing such an amazing tool – I think the maths involved must be pretty serious.

  13. The diameter of the strings have no influence on the result. On the one hand, that is understandable, but than, why bother filling them in. On the other hand you could want the spacing between the strings to be the same, and than the diameter of the strings do matter, but the results of the spacing should be adjusted for different diameters. Or am I missing something here?

    • It’s the latter case, the space between the strings is the same. The diameter of the strings does influence the result.

  14. If you are trying to recreate American designed guitars, using the same units as the inventors is important. If Leo Fender used imperial units, it would be more accurate to use imperial units.

    If you are building something totally original, then preference is key. If you prefer imperial units, this website won’t cater to your needs regardless of whether or not it is a better system.

    • I’m puzzled by DL’s statement. it matters not a whit what units of measurement you use. If done correctly the slots will be in the same place.

    • There are 3 countries in the world that DO NOT use metric units. USA – Myanmar – Liberia, and I think two are seriously looking at switching. Your argument is a little ridiculous. The units makes no difference to get the same dimension. Most of the people in the world are metric it would do you a service to learn it. Here is the first lesson – 1 inch = 25.4mm

      Regards Peter.

  15. Thank you very much for this tool! I’m building my first electric guitar ever and I also filed the first nut to Yamaha CS-40 succesfully with this calculator :)

  16. This is a great tool. Although I play 6 string guitar, I mostly play four string, i.e., tenor and baritone uke. Do you have or know of a similar tool for 4 string instruments. I am in the process of modifying a Fender Squire Mini Strat to a 4 string electric tenor and am almost to the point of installing a new zero glide nut. I know what spacing I want but will have to do it trial and error.

  17. Please give an option for imperial units. Pretty silly to have both in the same calculator.

    • It isn’t silly at all.

      The vast majority of people measure in metric and string gauges are generally described in thousandths of an inch so it’s using the units that most people are comfortable with.

      • Good answer. My nut files are graded in thousands of an inch, as per the string gauges, but the nuts I purchase are all given in metric which I find to be more more accurate when measuring out and fitting a new nut. However, I still have to go online and convert measurements when I get information from the USA since imperial units are the overriding unit of measurement still. This calculator is an excellent tool and saves a lot of time for those who are not expert luthiers but DIY guitarists doing their own small repair jobs.

      • Well said. All these people complaining when they’ve been given something for free!! Rather entitled.

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