Free Guitar String Tension Calculator for Any Tuning and Gauge

The calculator uses the D’Addario standard tension formula: T = UW times (2 times L times f) squared, divided by 386.4. T is tension in pounds, UW is the string’s unit weight in pounds per inch (from D’Addario’s published specifications), L is scale length in inches, and f is the target pitch frequency in Hz. The gravitational constant 386.4 converts the result to pound-force in US imperial units. Big.js arbitrary-precision arithmetic is used to prevent floating-point rounding errors in the calculation.

Unit weight is the mass of a string per unit length, measured in pounds per inch. For plain steel strings, it is calculated from the physics of steel density using the formula UW = 0.0002215 times diameter squared. For wound strings, the winding material adds mass that the diameter-only formula cannot predict, so manufacturers publish measured unit weight tables. This calculator uses D’Addario’s published String Tension Specifications guide for nickel-wound electric, phosphor-bronze acoustic, and bass string unit weights. Exact values vary by manufacturer and between production batches, so results are accurate to within approximately 1 to 3 pounds per string compared to real-world measurements.

Most electric guitar players prefer individual string tension between 13 and 18 lbs per string, with the wound strings (4th through 6th) typically running somewhat higher than the plain strings (1st through 3rd). Below about 8 to 10 lbs per string, the string will feel noticeably floppy and may lose intonation under playing pressure. Above 22 lbs per string, most players find bending difficult and the overall feel uncomfortably stiff. Total set tension for a 6-string electric typically runs 90 to 130 lbs, with the popular 10-46 set at standard tuning on 25.5 inches producing approximately 106 lbs.

Because tension scales with the square of frequency. The tension formula includes (2Lf)^2, which means that reducing the pitch reduces tension by the square of the frequency ratio. Dropping from Standard E to Drop D lowers the low string from 82.41 Hz to 73.42 Hz, a ratio of 0.8909. Squared, that is 0.7937, meaning the string loses about 20.6% of its tension. If it pulled 16.7 lbs at E, it pulls about 13.2 lbs at D. This is a significant change in feel, which is why dedicated drop tuning players use heavier strings on the low string to restore tension and responsiveness.

Phosphor bronze winding is denser than nickel winding, giving phosphor-bronze acoustic strings a higher unit weight than nickel-wound electric strings at the same outer diameter. For example, a .026 nickel-wound string has a unit weight of approximately 0.000139 lb/in, while a .026 phosphor-bronze string has approximately 0.000139 lb/in also (they happen to be very similar at .026), but at larger gauges the difference becomes more significant. This is why acoustic guitar sets produce higher total tension than electric sets of the same gauges: the acoustic wound strings are heavier per inch. Acoustic guitars are built with stronger bracing and thicker tops to handle this additional tension.

Enter your current string set in the string editor (or load a preset), then click Compare Tunings. Select your current tuning as Comparison A and your target alternate tuning as Comparison B. The table shows the tension change for each string. Any string that shows a large negative difference (dropping below your comfort threshold) needs a heavier gauge in the alternate tuning. Strings with small changes or positive differences can stay the same gauge. This targets your string purchase: you often only need to change one or two strings for alternate tunings rather than buying a completely new set.

Yes, for any scale length and tuning that falls within the calculator’s range (8 to 40 inches). The string editor lets you add the gauge and type for any string, and the tuning selector includes B Standard and Drop A options that cover 7-string low strings. For 8-string guitars with an ultra-low string, use the Custom option in the tuning selector and enter the exact frequency of the low string in Hz. The tension formula works for any fretted string instrument.

Total neck tension represents the combined pulling force all strings exert on the neck, nut, and bridge simultaneously. A typical 6-string electric at 100 to 110 lbs is within the design envelope of all standard electric guitar neck construction. Acoustic guitars, built to handle 150 to 185 lbs from phosphor-bronze strings, have heavier bracing. Vintage acoustic guitars from the pre-electric era were often designed for lower-tension gut strings and may show structural issues when strung with medium steel sets at 180 lbs or more. When significantly increasing total tension (more than 15 to 20 lbs), check neck relief 24 hours after the change and adjust the truss rod if the neck has bowed forward noticeably.

NW stands for Nickel Wound, the most common electric guitar wound string construction. PB stands for Phosphor Bronze, the standard acoustic guitar wound string material. PS stands for Plain Steel, which is used for the unwound treble strings on both electric and acoustic instruments. BW stands for Bass Wound, used for bass guitar strings. The type selector changes which unit weight table the calculator uses: plain steel uses the physics-derived formula, nickel wound uses D’Addario’s published electric string specs, and phosphor bronze uses D’Addario’s published acoustic string specs. Using the wrong type for a string will produce incorrect tension values.

Results typically match D’Addario’s own published tension values to within 1 to 3 lbs per string. The EverTune bridge manufacturer, who has physically measured string tensions for their bridge design, reports up to 3 lb differences between the same gauges of wrapped strings from different manufacturers and production batches. This variability comes from slight differences in core wire diameter, winding tightness, and core-to-wrap ratio between manufacturers and even between batches from the same manufacturer. Use this calculator for planning and comparison purposes: the relative changes between gauges and tunings are accurate even where absolute values may vary slightly from any specific string.

The truss rod counteracts the forward pull of the strings on the neck. When string tension increases, the neck tends to bow forward, raising the action and making the guitar harder to play. When tension decreases, the neck may straighten or even back-bow, causing fret buzz in the lower positions. Any change in total neck tension of more than 10 to 15 lbs warrants checking and potentially adjusting the truss rod after 24 to 48 hours of string settling. Always retune to pitch after the change and let the new strings stretch before checking neck relief, since new strings and the wood both need time to reach their equilibrium state.

DADGAD (D2, A2, G3, D3, A3, D4) reduces the first, third, and sixth strings by a whole step compared to Standard E. On a 25.4-inch acoustic scale with 12-53 phosphor-bronze strings, the total tension drops from approximately 165 lbs to about 150 lbs. The first string (high E dropped to D) loses about 20% of its tension, which can feel quite loose at .012. Many DADGAD players move to a 13-56 set specifically to compensate, bringing the dropped strings back to a tension comparable to a 12-53 set at Standard E. The comparison tool will show you exactly what happens to each string when you switch tunings.

Classical nylon strings have a fundamentally different construction and material density than steel strings, and D’Addario’s nickel-wound and phosphor-bronze unit weight data does not apply to them. Nylon treble strings use extruded nylon monofilament, and classical bass strings use nylon multifilament cores with silver or bronze winding. The tension formula (T = UW x (2Lf)^2 / 386.4) still applies, but the unit weight values are different. This calculator does not currently include nylon string unit weight data. For classical guitar string tension, D’Addario publishes a separate tension chart for their nylon string lines (Pro-Arte series) on their website.

A hybrid string set uses lighter gauges for the treble strings (which need to be easy to bend) and heavier gauges for the bass strings (which need more tension for low-end definition). Common hybrid configurations for drop tunings include 9-46 (lighter top, heavier bottom than a pure 9-42), 10-52, and 10-56. The string editor in this calculator lets you enter any combination of gauges per string, so you can model hybrid sets that do not correspond to any commercially available set and find exactly which gauges give you the tension you want on each individual string. This is particularly useful for multi-drop tunings where different strings need different tension compensations.

Yes to both. The calculator is completely free, requires no account, and runs in any modern mobile or desktop browser without downloading an app. All preset loading, gauge editing, tension calculation, and the tuning comparison work on touch screens. The string gauge input fields are sized for fingertip accuracy, and the per-string result cards and chart reflow cleanly on small screens. The PDF download and WhatsApp share also work on mobile, making it practical to use at the music store when comparing string sets or at the repair bench when planning a setup change.

The PDF report includes the instrument type, scale length, tuning name, and a summary of total neck tension with the health rating at the top. The main table shows each string’s name, note, gauge, string type, tension in pounds, tension in kilograms, and feel verdict. The total row at the bottom shows combined tension and the health label. A footer note clarifies that results are planning estimates and may vary by approximately 1 to 3 lbs per wound string compared to any specific brand’s actual production values. The file is named with the instrument type and scale length for easy archive organization.