Find tension from unit weight, scale, and frequency. Test tunings with instant exports and graph. Reduce guesswork when selecting gauges for stable playing feel.
This table shows sample scenarios for quick comparison. Diameter based rows are approximations, so wound strings should be checked with measured unit weight whenever possible.
| Example | Scale Length | Frequency | Material | Diameter | Approx. Tension |
|---|---|---|---|---|---|
| Plain steel .010 at E4 | 25.50 in | 329.63 Hz | Steel | 0.010 in | 16.304 lbf |
| Plain steel .013 at B3 | 25.50 in | 246.94 Hz | Steel | 0.013 in | 15.464 lbf |
| Plain steel .017 at G3 | 25.50 in | 196.00 Hz | Steel | 0.017 in | 16.659 lbf |
| Nylon .028 at G3 | 25.60 in | 196.00 Hz | Nylon | 0.028 in | 6.673 lbf |
String tension follows the wave relation between vibrating length, frequency, and linear density. The direct method uses measured unit weight, which is the best choice for wound guitar strings.
Direct tension formula: T = UW × (2 × L × f)2 / 386.4
Here, T is tension in pounds force, UW is unit weight in pounds per inch, L is scale length in inches, and f is frequency in hertz.
SI form: T = μ × (2 × L × f)2
In SI units, μ is linear density in kilograms per meter, L is meters, and T is newtons.
Estimated linear density from diameter and density: μ = ρ × π × (d / 2)2
This solid cylinder estimate works well for plain strings. Wound strings contain gaps and different core to wrap ratios, so measured unit weight gives better practical accuracy.
Start by entering the guitar scale length. Then choose a reference note and add a cents offset if you need a slight pitch correction. You can also type a custom frequency when matching alternate reference tunings.
Next, pick the calculation mode. Use measured unit weight when your string maker publishes linear density. Use diameter and material density when you want a quick estimate for plain strings or educational comparisons.
After you submit the form, the tension result appears above the calculator. Review the graph to see how tension changes across nearby semitone shifts. Then export the result to CSV or PDF for setup notes, lesson plans, or repair records.
Guitar string tension connects pitch, scale length, and linear density through basic wave physics. A longer scale or a higher frequency raises tension quickly because the vibrating speed must increase. That is why the same gauge feels tighter on a longer instrument, and why tuning up a few semitones can noticeably stiffen the response.
Material also matters. Plain steel, nickel alloys, bronze wraps, and nylon all change mass per unit length. When that mass changes, the string needs a different pull to reach the same pitch. Luthiers and players often compare tension before changing string sets because it affects feel, neck load, intonation behavior, and picking response.
This calculator supports two practical workflows. The first uses measured unit weight, which is the preferred method for accurate real world setups. The second estimates linear density from diameter and material density, which is useful for learning, quick checks, and plain string experiments. The graph helps visualize how small tuning moves affect load, making it easier to compare standard tuning, drop tunings, or alternate pitch references.
Use the output as a decision aid, not as the only safety rule. Vintage instruments, floating bridges, tremolo systems, and mixed string constructions may respond differently even when the calculated tension looks similar. Comparing several scenarios before restringing can help you move toward a stable, comfortable setup with less guesswork.
It estimates the pull needed for a guitar string to reach a chosen pitch at a chosen scale length. The result is shown in pounds force, newtons, and kilograms force.
Measured unit weight is better. Wound strings are not solid cylinders, so diameter plus bulk density can miss the true mass distribution and change the final tension estimate.
Yes, if pitch and string properties stay fixed. A longer speaking length raises the required wave speed, so the tension must increase to keep the same note.
It lets you override equal tempered note values. That is useful when checking nonstandard reference pitch, measured frequencies, or alternate tuning systems during setup work.
Yes. The graph plots tension from six semitones below to six semitones above the selected pitch, so you can see how nearby retuning changes the load.
Yes. Compare your current string tension with proposed strings or tunings. Matching total feel more closely can make transitions between sets less surprising.
Not in this model. The calculation uses vibrating length, frequency, and linear density. Action can affect playing feel, but it is not a main input here.
No. It is a physics estimate and comparison tool. Always consider manufacturer guidance, instrument age, hardware condition, and structural limits before large tuning or gauge changes.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.