Ukulele string spacing
Kala's concert ukulele (KA-C) has a 1-7/16″ (36.5 mm) nut, the soprano KA-15S 1-3/8″ (34.9 mm) and the Tenor XL 1-1/2″ (38.1 mm). StewMac's ukulele bridge is drilled for a 1-5/8″ (41 mm) string spread.
Ukulele string positions
Each string's position from the center of the 4th string (G), with an equal clear gap between strings: 41 mm at the bridge, 29.5 mm at the nut (estimate), Aquila 7U.
| String | Gauge | Bridge (mm) | Nut (mm) |
|---|---|---|---|
| 4 | .028 | 0.00 | 0.00 |
| 3 | .038 | 13.68 | 9.85 |
| 2 | .032 | 27.42 | 19.75 |
| 1 | .026 | 41.00 | 29.50 |
How to use it
- Choose bridge or nut; 41 mm or 29.5 mm fills in. If you're replacing a nut, measure the old one and enter that instead.
- Gauges go in playing order, G C E A. For low G, replace the first gauge with your wound G and the gaps recalculate.
- Most ukulele fingerboards are flat; skip the radius section, or use 20″ for a slightly curved nut.
Help and explanations
Kala doesn't publish the spacing at the nut. The 29.5 mm loaded here between the G and A is an estimate, interpolated between two Graph Tech ukulele nuts: 28.85 mm on a 35.7 mm nut and 30.2 mm on a 37.45 mm one. The gauges are an Aquila 7U concert set (G .028, C .038, E .032, A .026, high G).
String by string
At the nut, with 29.5 mm between the G and A, equal gap leaves 9.01 mm of clear space; the centers come out at 9.85, 9.90 and 9.75 mm, against 9.83 mm with equal centers. With gauges this close, either method works. On a 36.5 mm nut that leaves 3.16 mm from each outer string to the edge.
At the bridge, 41 mm gives 13.67 mm from string to string. On a tie bar bridge, drill the holes on those centers and the strings will run straight over the saddle.
Soprano, concert and tenor
The nut grows less than the scale. Kala's soprano (13.625″ scale, 346 mm) and concert (14.8125″, 376 mm) differ by only 1.6 mm at the nut, 34.9 against 36.5 mm. At the neck joint the KA-C is 1-3/4″ (44.45 mm) wide.
Graph Tech marks its 1257 ukulele nut R-20, most likely a slight 20″ curve, while retailers list Kala's KA-15S with a flat fingerboard. A 20″ curve across a 36.5 mm nut rises only 0.33 mm in the middle.
Tips
- Copying an old nut? Its slot centers matter more than its length; with Aquila gauges a reading across the outside of the G and A is only about 0.7 mm larger.
- New nut or saddle? Check the ukulele action afterwards.
- Fluorocarbon and nylon strings of the same note differ in diameter: compare sets in the string tension calculator.
Frequently asked questions
What is the string spacing on a ukulele bridge?
StewMac drills its ukulele bridge for 1-5/8″ (41 mm) between the outer strings, about 13.7 mm from string to string.
What is the nut width of a concert ukulele?
1-7/16″ (36.5 mm) on Kala's KA-C. The KA-15S soprano is 1-3/8″ (34.9 mm) and the Tenor XL 1-1/2″ (38.1 mm).
What is the string spacing at a ukulele nut?
Kala doesn't publish it. Graph Tech's nuts suggest about 29.5 mm between the G and A on a concert nut, roughly 9.8 mm from string to string (an estimate).
Is a ukulele fingerboard radiused?
Usually not: retailers list Kala's KA-15S as flat. Graph Tech marks one of its ukulele nuts R-20, which suggests a slight 20″ curve.
Does a low G string change the spacing?
If you keep the old slots, the centers stay put and the thicker wound G leaves less clear space next to the C; its slot usually needs widening too. Enter the new gauge and the table recalculates an even gap.