Fret Position
Calculate precise guitar fret positions from scale length and number of frets. Get exact distances from nut with fret spacing chart for any string instrument. Free online tool.
About This Calculator
The Fret Position Calculator is a precision tool for luthiers, guitar builders, and musicians who need exact fret placement on a guitar, bass, or other stringed instrument fingerboard. By entering the instrument's scale length and desired number of frets, the calculator uses the standard 12-tone equal temperament formula to compute the precise distance from the nut to each fret.
The formula behind fret positioning is rooted in the physics of sound. Under equal temperament — the most common tuning system in Western music — the distance from the nut to the nth fret equals the scale length multiplied by (1 − 2−n/12). This means each fret shortens the vibrating string length by the 12th root of 2, producing the 12 semitones of an octave. The 12th fret will always land at exactly half the scale length, which serves as a built-in verification of correct fret layout.
Common scale lengths include 25.5 inches (Fender Stratocaster, Telecaster), 24.75 inches (Gibson Les Paul, SG), and 25 inches (many steel-string acoustics). Bass guitars typically use a 34-inch scale. For classical guitars, 650 mm (approximately 25.6 inches) is standard. The calculator supports both imperial (inches) and metric (millimeters) units.
The results show each fret's cumulative distance from the nut as well as the interval (space) between consecutive frets. A bar chart visualizes the fret progression along the fingerboard. The breakdown table lists every fret position to three decimal places for maximum precision in your fret slot cutting.
Frequently Asked Questions
What is a fret position calculator?
A fret position calculator determines the exact placement of frets on a guitar or other stringed instrument fingerboard. It uses the standard 12-tone equal temperament formula to calculate each fret's distance from the nut based on the instrument's scale length.
What is the formula for fret spacing?
Fret positions follow the 12th root of 2 formula under equal temperament. The distance from the nut to fret n is scale length times (1 minus 2 to the power of negative n divided by 12). The 12th fret is always exactly halfway along the scale length, confirming the octave.
What scale length should I use for my guitar?
Standard guitar scale lengths are 25.5 inches for Fender Stratocaster and Telecaster, 24.75 inches for Gibson Les Paul and SG, 24 inches for PRS, 25 inches for many acoustics, and 34 inches for bass guitars. Measure from the nut to the middle of the 12th fret and double it for your scale length.
How many frets should I use?
Most electric guitars have 21, 22, or 24 frets. Classic guitars often have 19 frets. Acoustic guitars typically have 20 frets. Bass guitars commonly have 20 or 24 frets. Enter your desired number of frets into the calculator to get exact positions.
What unit should I use — inches or millimeters?
Use whichever unit you are comfortable with. Inches are common in US guitar building (e.g., 25.5 inch scale), while millimeters are standard for metric measurements worldwide. Our calculator supports both units and labels results accordingly.
Why is the 12th fret exactly at half the scale length?
The 12th fret corresponds to one octave above the open string. In equal temperament, doubling the frequency halves the string length. Therefore the 12th fret is always positioned at exactly half the scale length from the nut, regardless of the instrument.