Configure bridge spacing
Use the bridge measurement basis that matches your drawing, ruler, calipers, or supplier specification.
Formula used
Equal center spacing: center gap = usable outer-center span ÷ (string count − 1).
Clear gap: clear gap = center gap − (adjacent gauge 1 + adjacent gauge 2) ÷ 2.
Equal clear-gap spacing: the calculator first removes all string-radius contributions from the usable span, then divides the remainder across the intervals.
Progressive spacing: each interval receives a weighted share. Positive percentages enlarge later intervals; negative percentages enlarge earlier intervals.
How to use this calculator
- Choose inches or millimetres and enter the number of strings.
- Select the width basis that matches your bridge measurement.
- Enter the measured width, plus edge clearances only for physical bridge width.
- Paste gauges from left to right and choose a spacing method.
- Calculate, inspect clear gaps, review the graph, then export the layout.
Example data table
| Setting | Example value | Purpose |
|---|---|---|
| String count | 6 | Standard six-string layout. |
| Outer center span | 2.05 in | Distance between outer string centerlines. |
| Method | Equal center-to-center | Keeps all center intervals uniform. |
| Gauges | .046, .036, .026, .017, .013, .010 in | Supports clear-gap analysis. |
| Expected average | 0.4100 in | 2.05 ÷ 5 intervals. |
Bridge String Spacing Basics
Bridge string spacing is the lateral distance between adjacent strings near the bridge. It shapes picking comfort, fingerstyle clearance, muting control, and saddle placement. Small changes feel significant. Players notice it during fast passages or wide chords.
The calculator starts with usable outer-string center span. This is the distance between centerlines of first and last strings. You may enter physical bridge width instead. Then side clearances and end-string diameters determine available span. This distinction avoids a common measurement error.
Equal center spacing keeps every centerline interval identical. It suits many modern electric guitars and basses. Equal clear-gap spacing keeps open air between string edges identical. This can look balanced when gauges vary widely. Progressive spacing gradually changes each centerline interval. It can give heavier bass strings more room or create preferred hand feel.
Why Gauge Data Matters
String diameter changes the visible and playable gap. A twelve-string set, heavy bass set, or mixed-gauge design can benefit from detailed gauge inputs. Enter diameters in the selected unit. A comma-separated list lets the calculator estimate every edge-to-edge space. When fewer gauges are supplied, the last supplied gauge repeats.
Margins describe distance from a physical bridge edge to a string’s outside edge. They are useful when width is measured across the bridge body. Use zero margins only when entered width already represents intended outer-string centers. Check the basis before comparing results from different manufacturers.
Understanding Results
The output table shows every string center position, adjacent center spacing, and adjacent clear gap. Center positions begin at the left outer-string center. The first string has no preceding gap. Negative clear gaps indicate that a selected span is too narrow for entered diameters. Increase bridge width, reduce margins, or choose a realistic gauge set.
The graph provides a visual check. Wide marker positions reveal string spread. Uneven intervals reveal progressive spacing. Use the download buttons to save calculations and input assumptions. Keep the record when designing a replacement bridge, nut, saddle block, or custom instrument.
Practical Setup Notes
Measure with calipers where possible. Confirm whether a catalog value uses outer centers, outside edges, or saddle slots. Compare the calculated result with the neck, pickup pole pieces, and playing style. Bridge spacing must also leave safe edge clearance across the fretboard near the highest frets. A comfortable layout balances symmetry, clearance, and the player’s preferred technique.
Frequently asked questions
1. What does outer-center spacing mean?
It is the distance from the center of the first string to the center of the last string. This is the most common value used when comparing bridge saddle spacing.
2. Why can clear gaps differ with equal center spacing?
Different string diameters occupy different widths. Equal center-to-center intervals remain constant, while the open air between edges becomes slightly different.
3. Which width basis should I use?
Use outer centers when that measurement is known. Use outside edges for an edge-to-edge bridge specification. Use physical bridge width when you also measured safe side clearances.
4. Are margins needed for every calculation?
No. Margins matter only when the entered value is a physical bridge width. They are ignored when you already enter the intended outer-string center span or outside-edge spread.
5. What does a negative clear gap mean?
It means adjacent strings overlap according to the entered values. Increase usable span, lower edge clearances, or verify the gauges and units.
6. Can this calculator handle bass guitars?
Yes. Enter the bass string count, bridge measurement, and actual diameters. Equal clear-gap mode is useful when large gauge differences affect visual symmetry.
7. What is progressive spacing useful for?
Progressive spacing changes interval size across the bridge. It can provide more room near heavier strings or match a custom ergonomic preference.
8. Does bridge spacing need to match nut spacing?
No. Strings commonly fan outward from nut to bridge. Check neck taper and fretboard edge clearance to ensure the full path remains comfortable.
9. Should gauges be entered in string order?
Yes. Enter gauges from the leftmost displayed string to the rightmost displayed string. For a typical right-handed guitar view, that is often bass to treble.
10. Is this suitable for machining saddle slots?
It provides a layout calculation, not machining certification. Verify dimensions with calibrated tools, manufacturer tolerances, and the actual saddle geometry before cutting material.
11. Can I export results for a build sheet?
Yes. The CSV export creates a spreadsheet-ready result table. The PDF export includes the project name, measurement summary, and calculated string positions.