Just to be clear, the "fret" is the metal bar. So on a right-handed bass, your white arrow is pointed at the 11th fret. You don't measure from any of the dots you have added.
You measure from where the string comes off the nut...
...to the middle of the 12th fret.
I measure along the course of the G string, which would be where I put the orange arrow.
Doubling that measure will give you the exact scale length. I measure the along the G string because it's the one that will be 30 inches on a 30 inch scale. All the other strings will be a little longer which you compensate for by adjusting the bridge saddles.
Nuts and saddles get measured where the string comes off. The fret gets measured in the middle of the metal bar.
You do the measurement from the nut to the 12th fret to test how long the scale length is. For example, if it is exactly 15 inches you have a 30 inch scale. If it is exactly 15.25 inches, then you have a 30.5 inch scale*. You can then measure (a) from the nut to the saddle, or (b) from the 12th fret to the saddle, whichever is easiest. I usually measure from the nut because I find it easier to rest my straight edge against the nut to do the measurement, but either way works.
*this is common on Gibson short scale basses.
Last edited by fender3x; 18-01-2026 at 06:54 AM.
Thank you very much. Greetings from Galicia
Hi guys: Both your comment and Trevos Davies' have helped me a lot. The only doubt I have left is that you both recommend that to take the measurement from the 12th fret to the saddle, it should be almost at the end. Wouldn't it be more logical for it to be in the middle to have room for adjustment? Sorry for my ignorance.
To correctly intonate the strings it works out that the thicker the string, the longer it needs to be. This can be seen in the image below. The E string is the longest, while the G string is the shortest. On the guitar shown there is about 6 mm difference in length between the G and E strings.
If you put the G string in the middle of the adjustment screw, then the thicker (D, A, E) strings will need to be further back. Then you run the risk of not having enough room for the E string. So, it is best to have the D and A string saddles about the middle of the adjustment screw.
The annoying part is that the scale length is roughly the length of the thinnest string. Therefore, position the G string saddle to be further forward.
I'm sure the saddle used in your kit is the same as in my picture - it has a lot of room for adjustment.
Last edited by Trevor Davies; 25-02-2026 at 07:47 PM.
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Like TD said, almost all of the adjustment will be away from the nut on the E A and D strings (in that order). On my favorite 34" scale bass, the distance between the nut and the center of the 12th fret was 431mm. That means the "true" scale length should be 862mm. After intonating all the strings, the G string intonated at pretty close to exactly 862mm. I didn't have to move the G string saddle at all to intonate--and that is typical. Even so, I had it set back about 3mm from maximum extension toward the nut--which is more adjustment toward the nut than I needed. The E string intonated at 7.63mm farther from the nut than the G string. You can see the difference in the picture.
In retrospect I probably should have set the bridge back another 1 or 1.5 mm farther away from the nut. As you can see the spring on the E string saddle is very compressed and would not have given me much more movement back if I had needed it. The great thing about these adjustable bridges is that there is enough adjustability in them so that you can be off by a couple of mm without too much problem.![]()