EverTune Calculator
Optimize your guitar string tension and saddle configuration
16.22 lbs
Standard Tension
329.63 Hz
0.0000221 lbs/in
Tension Profile (Gauge vs. Tension)
This chart shows how tension changes as you increase string gauge for your selected pitch.
What is an EverTune Calculator?
An evertune calculator is a specialized engineering tool designed for guitarists and luthiers to determine the exact physical tension exerted by a vibrating string. Unlike standard bridges, the EverTune system relies on a complex spring mechanism to maintain constant tension. For the bridge to function correctly, the calculated tension must fall within the mechanical limits of the specific saddle installed in the guitar.
Using an evertune calculator is essential when changing tunings (like drop-tuning) or switching to heavy-gauge strings. If the tension is too low, the string will “float” and lose the EverTune benefit; if it’s too high, the spring will bottom out. Professional players use this data to select between Low, Standard, and High tension saddles to ensure their instrument stays in tune regardless of humidity, temperature, or aggressive playing styles.
Many players often confuse total string tension with “feel.” While related, the evertune calculator provides the hard mathematical data required to choose the right bridge setup components. By understanding these metrics, you can achieve a perfectly balanced tension across the entire fretboard.
EverTune Calculator Formula and Mathematical Explanation
The math behind the evertune calculator is based on Mersenne’s Law for vibrating strings. The formula solves for Tension (T) using the frequency, scale length, and mass of the string.
The Core Formula:
T = (UW × (2 × L × f)²) / 386.4
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| T | Total Tension | Pounds (lbs) | 10 – 45 lbs |
| UW | Unit Weight | lbs/linear inch | 0.00002 – 0.0006 |
| L | Scale Length | Inches (in) | 24.0 – 30.0 |
| f | Frequency | Hertz (Hz) | 80 – 400 Hz |
The constant 386.4 is the acceleration of gravity in inches per second squared, used to convert mass-based units into force (pounds of tension). The evertune calculator automates this conversion, accounting for string material densities such as nickel and stainless steel.
Practical Examples (Real-World Use Cases)
Example 1: Standard E Tuning (25.5″ Scale)
A player uses a standard 0.010 gauge high E string on a Strat-style guitar. The evertune calculator inputs would be: Scale (25.5″), Pitch (329.63 Hz), and Gauge (0.010″). The result is roughly 16.2 lbs of tension. This falls perfectly into the Standard Tension Saddle range (10-28 lbs).
Example 2: Drop F Tuning (27″ Baritone)
A metal guitarist wants a low F1 note on a 27-inch scale using a thick 0.074 gauge string. The evertune calculator calculates the tension at approximately 19.5 lbs. While the string is very thick, the low pitch keeps the tension within the Standard saddle’s limits, though a drop tuning guide might suggest checking the nut slot width as well.
How to Use This EverTune Calculator
Follow these steps to get accurate results from our evertune calculator:
- Enter Scale Length: Measure from the nut to the bridge saddles. Most common lengths are 25.5″ (Fender) or 24.75″ (Gibson).
- Select Gauge: Input the decimal diameter of the string (e.g., 0.046 for a low E in a 10-46 set).
- Choose Target Pitch: Select the note you intend to tune the string to.
- Review Results: The primary result shows the tension. Check the “Recommended Saddle” box to see if you need to swap your hardware.
- Copy Results: Use the copy button to save your settings for future bridge setup reference.
Key Factors That Affect EverTune Calculator Results
- Scale Length Effect: Increasing the scale length significantly increases tension if the pitch and gauge remain the same. This is why baritone guitars feel “tighter.”
- String Gauge Guide: Thicker strings have more mass (Unit Weight), resulting in higher tension. Using a string gauge guide helps balance tension across a set.
- Material Density: Stainless steel is slightly lighter than nickel-plated steel, resulting in marginally lower tension for the same diameter.
- Core vs. Wrap: On wound strings, the ratio of the core wire to the wrap wire affects mass. Our evertune calculator uses industry-standard averages for these calculations.
- Frequency (Pitch): Pitch has a squared relationship with tension. Raising a note by one octave quadruples the tension.
- Intonation Adjustments: Moving the saddle back for intonation adjustment effectively increases the scale length slightly, though usually not enough to move out of a saddle’s range.
Frequently Asked Questions (FAQ)
Yes, as long as the resulting tension falls between 10 lbs and 45 lbs. You must choose the correct saddle (Low, Standard, or High) to match the tension calculated by the evertune calculator.
The saddle will stay in “Back Stop” mode, meaning the EverTune will act like a fixed bridge and won’t compensate for tuning deviations. You would need a “Low Tension” saddle.
Absolutely. A longer scale length effect means higher tension for the same gauge/pitch, which might require a different saddle type.
It is very similar, but small differences in core wire diameter can cause slight variations from the evertune calculator results.
EverTune makes bass bridges; however, the tension ranges are different. This evertune calculator is optimized for 6, 7, and 8-string electric guitars.
Most EverTune-equipped guitars ship with Standard saddles (10-28 lbs). High and Low saddles are typically aftermarket upgrades.
No, but the total tension of all strings combined exerts significant force on the neck. Most necks handle 150-200 lbs of total tension easily.
Physical tension changes with temperature, but the EverTune’s job is to adjust the spring to maintain the constant tension you calculated.
Related Tools and Internal Resources
- Guitar String Tension Guide: A deep dive into the physics of playability.
- Drop Tuning Calculator: Find the perfect gauge for low-tuning setups.
- Guitar Setup Pro: Step-by-step instructions for professional intonation.
- Scale Length Tool: Compare how different scales change your instrument’s feel.
- Intonation Mastery: How to set up your EverTune for perfect octaves.
- EverTune Installation: Guide for routing and installing the bridge system.