Guitar Nut String Spacing Calculator

Guitar setup · Equal edge spacing

Guitar Nut Spacing Calculator

Lay out string-slot centers with equal clear space between adjacent string edges. Enter every measurement in one unit, bass to treble.

Production-authorized calculation · Formula 1.0.0

Set the nut geometry

Choose the unit and define how the two outer margins are measured.

Measurement unitChanging units converts the current measurements.Outer margin basisApplied symmetrically at the bass and treble sides.String countSupports 2 through 8 strings in a single course.

Nut width

Overall width of the nut blank.

Outer margin

Distance from each nut edge to the nearest outer string edge.

Enter string diameters, bass to treble

List the installed set from the lowest bass string to the highest treble string.

String 1 diameter

Bass position · string 1 of 6

String 2 diameter

Inner position · string 2 of 6

String 3 diameter

Inner position · string 3 of 6

String 4 diameter

Inner position · string 4 of 6

String 5 diameter

Inner position · string 5 of 6

String 6 diameter

Treble position · string 6 of 6

Results

Your spacing result and slot positions will appear here.

Ready for your measurementsThe result will include the equal edge gap, outer center span, and every slot center measured from both sides.

Measured guitar nut layout

Lay out equal guitar nut slot spacing from real string gauges

Turn a measured full nut width, one symmetric outer margin, and actual string diameters into equal clear gaps and auditable slot-center marks. Enter 2–8 strings in physical bass-to-treble order, keep every dimension in one unit, and verify the layout on the instrument before a file touches the nut.

Step-by-step guide · Measured guitar nut layout

Enter every string in its physical bass-to-treble order

Spacing rule: Equal clear gaps between strings
Outer margin: Symmetric edge or center basis
Output: Centers from bass and treble references

Match the count to the gauge list
Enter one positive diameter for each physical string, starting at the bass side and ending at the treble side. A six-string layout therefore needs six entries. The supported range is 2–8 individual strings. Copy the actual set rather than assuming a generic guitar or bass gauge, and confirm which side of the instrument you are treating as the bass reference.
Set one symmetric outer margin
Enter the margin that should be applied at both the bass and treble ends, then identify whether it reaches the outside string edge or its center. The form deliberately uses one symmetric value; it cannot represent different bass- and treble-side margins. If the design needs asymmetric clearance, calculate and review that layout separately instead of averaging the two sides.
Reject impossible geometry instead of squeezing it
The nut width must have room for both applications of the outer margin, the relevant portions of all entered string diameters, and a positive clear gap between every adjacent pair. A mismatched gauge count, non-positive diameter, or exhausted spacing budget means the inputs cannot describe the requested arrangement. Recheck the basis and measurements rather than forcing the result to zero.

Lay out equal guitar nut slot spacing from real string gauges: The diameter list is geometry, not merely a description of the string set. Its count and order determine every following center position.

Define the reference before measuring the nut blank

The calculator always starts with the full bass-side to treble-side width of the nut along the proposed slot line. The outer-margin basis then answers a separate question: does the declared margin stop at the nearest outside edge of each outer string, or directly at that string's slot center? Those measurements are not interchangeable because an edge-based margin leaves another half-diameter before the center. Measure the actual workpiece instead of copying a nominal replacement-part width.

Choose millimetres or inches and keep the nut width, symmetric outer margin, and every string diameter in that unit. Gauge packaging often prints inches even when the instrument is measured in millimetres. Convert those values deliberately with the millimetres-to-inches calculator, then enter the converted diameters rather than mixing systems in one list. The calculator does not infer a unit from decimal places, and it does not accept a first-to-last string span in place of the full nut width.

Enter every string in its physical bass-to-treble order

The diameter list is geometry, not merely a description of the string set. Its count and order determine every following center position.

Match the count to the gauge list
Enter one positive diameter for each physical string, starting at the bass side and ending at the treble side. A six-string layout therefore needs six entries. The supported range is 2–8 individual strings. Copy the actual set rather than assuming a generic guitar or bass gauge, and confirm which side of the instrument you are treating as the bass reference.
Set one symmetric outer margin
Enter the margin that should be applied at both the bass and treble ends, then identify whether it reaches the outside string edge or its center. The form deliberately uses one symmetric value; it cannot represent different bass- and treble-side margins. If the design needs asymmetric clearance, calculate and review that layout separately instead of averaging the two sides.
Reject impossible geometry instead of squeezing it
The nut width must have room for both applications of the outer margin, the relevant portions of all entered string diameters, and a positive clear gap between every adjacent pair. A mismatched gauge count, non-positive diameter, or exhausted spacing budget means the inputs cannot describe the requested arrangement. Recheck the basis and measurements rather than forcing the result to zero.

Know what edge and center outer margins change

Both branches use the same full nut width and symmetric margin value, but they reserve different string material inside the measured boundaries.

Margin to each outer string edge

After subtracting the same outer margin from both ends, subtract every full string diameter. Divide the remainder by one fewer than the string count. The first slot center sits one half of the bass-string diameter beyond its margin, and the last center sits one half of the treble-string diameter beyond the opposite margin. This TLC-style geometry makes the clear edge reservations directly auditable.

Margin to each outer slot center

The two margins place the first and last centers directly. Between those centers, subtract half of the bass diameter, every complete interior diameter, and half of the treble diameter before dividing the remainder into equal clear gaps. This branch preserves the entered center offsets; it does not reinterpret them as visible clearance outside the strings.

Competitor span and paired-course modes

Nils Johnson's separate calculator can start from an overall first-to-last string span and can reserve a special gap inside paired courses. Those are useful but different input contracts. This page accepts neither an overall span nor paired-course spacing, so use it only for individual strings laid out from a full nut width and one symmetric outer margin.

Read the equal gap and every slot center together

The primary spacing result is a clear surface-to-surface gap, not a center distance. After that gap is solved, each following center advances by half the previous diameter, the equal clear gap, and half the next diameter. The result also reports the outside-string center span and both outer-slot offsets. The per-slot ledger lists each diameter and its center from the bass and treble sides so every mark can be cross-checked from either nut edge.

Keep full precision while positions accumulate across the nut. Rounding every intermediate step can produce a visible drift at the final string even when the nominal gap looks consistent. If workshop marks require fewer decimals, use the rounding calculator only after saving the unrounded result. The fraction calculator can convert a fractional-inch shop note to a decimal before entry, but a printed template must still be checked against a known dimension because browser and printer scaling can alter it.

Carry the calculated marks into the workshop cautiously

Spacing arithmetic provides transverse starting locations only. A playable nut still depends on measurements and craft decisions outside this calculator.

Confirm the actual playing orientation, nut width, string set, edge reference, and measurement basis on the instrument. Transfer a light center mark, then measure the first-to-last layout and both outer clearances again. A reversed gauge order can still produce tidy arithmetic while placing the heavy strings on the wrong side.
Choose slot width, file size, bottom profile, depth, break angle, and final action from the string, nut material, instrument geometry, setup target, and qualified workshop practice. A diameter is not automatically a file recommendation, and a horizontal center mark does not establish the safe depth of cut.
Evaluate fretboard-edge clearance, string binding, break angle, action, intonation, compensation, and playability separately. Make reversible marks and shallow initial cuts, then verify the work on the instrument. When the blank, neck geometry, or desired setup is uncertain, have an experienced luthier review the layout before material is removed.

Important limitations

The calculator locates slot centers only. It does not choose safe fingerboard-edge clearance, string set, slot depth, action, break angle, compensation, paired-course spacing, tool kerf, or final setup; verify a full-scale layout on the instrument before cutting.

Review the stated scope, calculation method, assumptions, supported inputs, and effective dates, and obtain qualified advice before using a high-stakes result.

This formula passed its registered engineering tests and is published under an explicit site-owner policy authorization. No independent expert, QA, editorial, legal, or third-party review is claimed. Verify consequential results with a qualified professional.

Measured guitar nut layout

Lay out equal guitar nut slot spacing from real string gauges

Step-by-step guide · Measured guitar nut layout

Enter every string in its physical bass-to-treble order

Spacing rule: Equal clear gaps between strings
Outer margin: Symmetric edge or center basis
Output: Centers from bass and treble references

Match the count to the gauge list
Enter one positive diameter for each physical string, starting at the bass side and ending at the treble side. A six-string layout therefore needs six entries. The supported range is 2–8 individual strings. Copy the actual set rather than assuming a generic guitar or bass gauge, and confirm which side of the instrument you are treating as the bass reference.
Set one symmetric outer margin
Enter the margin that should be applied at both the bass and treble ends, then identify whether it reaches the outside string edge or its center. The form deliberately uses one symmetric value; it cannot represent different bass- and treble-side margins. If the design needs asymmetric clearance, calculate and review that layout separately instead of averaging the two sides.
Reject impossible geometry instead of squeezing it
The nut width must have room for both applications of the outer margin, the relevant portions of all entered string diameters, and a positive clear gap between every adjacent pair. A mismatched gauge count, non-positive diameter, or exhausted spacing budget means the inputs cannot describe the requested arrangement. Recheck the basis and measurements rather than forcing the result to zero.

Define the reference before measuring the nut blank

Enter every string in its physical bass-to-treble order

The diameter list is geometry, not merely a description of the string set. Its count and order determine every following center position.

Match the count to the gauge list
Enter one positive diameter for each physical string, starting at the bass side and ending at the treble side. A six-string layout therefore needs six entries. The supported range is 2–8 individual strings. Copy the actual set rather than assuming a generic guitar or bass gauge, and confirm which side of the instrument you are treating as the bass reference.
Set one symmetric outer margin
Enter the margin that should be applied at both the bass and treble ends, then identify whether it reaches the outside string edge or its center. The form deliberately uses one symmetric value; it cannot represent different bass- and treble-side margins. If the design needs asymmetric clearance, calculate and review that layout separately instead of averaging the two sides.
Reject impossible geometry instead of squeezing it
The nut width must have room for both applications of the outer margin, the relevant portions of all entered string diameters, and a positive clear gap between every adjacent pair. A mismatched gauge count, non-positive diameter, or exhausted spacing budget means the inputs cannot describe the requested arrangement. Recheck the basis and measurements rather than forcing the result to zero.

Know what edge and center outer margins change

Both branches use the same full nut width and symmetric margin value, but they reserve different string material inside the measured boundaries.

Margin to each outer string edge

Margin to each outer slot center

Competitor span and paired-course modes

Read the equal gap and every slot center together

Carry the calculated marks into the workshop cautiously

Spacing arithmetic provides transverse starting locations only. A playable nut still depends on measurements and craft decisions outside this calculator.

Confirm the actual playing orientation, nut width, string set, edge reference, and measurement basis on the instrument. Transfer a light center mark, then measure the first-to-last layout and both outer clearances again. A reversed gauge order can still produce tidy arithmetic while placing the heavy strings on the wrong side.
Choose slot width, file size, bottom profile, depth, break angle, and final action from the string, nut material, instrument geometry, setup target, and qualified workshop practice. A diameter is not automatically a file recommendation, and a horizontal center mark does not establish the safe depth of cut.
Evaluate fretboard-edge clearance, string binding, break angle, action, intonation, compensation, and playability separately. Make reversible marks and shallow initial cuts, then verify the work on the instrument. When the blank, neck geometry, or desired setup is uncertain, have an experienced luthier review the layout before material is removed.

Set the nut geometry

Enter string diameters, bass to treble

Results

Match the count to the gauge list

Set one symmetric outer margin

Reject impossible geometry instead of squeezing it

Define the reference before measuring the nut blank

Enter every string in its physical bass-to-treble order

Know what edge and center outer margins change

Margin to each outer string edge

Margin to each outer slot center

Competitor span and paired-course modes

Read the equal gap and every slot center together

Carry the calculated marks into the workshop cautiously

Important limitations

Set the nut geometry

Enter string diameters, bass to treble

Results

Match the count to the gauge list

Set one symmetric outer margin

Reject impossible geometry instead of squeezing it

Define the reference before measuring the nut blank

Enter every string in its physical bass-to-treble order

Know what edge and center outer margins change

Margin to each outer string edge

Margin to each outer slot center

Competitor span and paired-course modes

Read the equal gap and every slot center together

Carry the calculated marks into the workshop cautiously