Guitar String Tension Calculator

How to use this string tension calculator

Choose electric or acoustic. This sets the string construction the math uses — nickel-wound for electric, phosphor bronze for acoustic — because two strings of the same gauge pull different tension depending on what they're made of.
Pick a gauge set. One tap loads a common factory set — from 9–42 super light up to 13–56 medium. The numbers update instantly; there's no "calculate" button.
Set your tuning. Standard, Drop D, E♭, D standard, Drop C, and three open tunings are built in. Lowering the pitch drops the tension, which is exactly when strings start to feel loose.
Set your scale length. A Gibson (24.75″), a Fender or acoustic (25.5″), a short-scale, or a 27″ baritone — or type any custom length. Longer scale = more tension at the same pitch.
Read the result and tweak. You get per-string tension, the total pull on the neck, and a feel verdict. Edit any gauge right in the table (in thousandths, e.g. 46) to model a custom set, then copy the result, save a link, or download a printable chart.

Why this tension calculator is different

Most "string tension calculators" are either a static chart locked to one scale and standard tuning, or a manufacturer database that makes you look up item numbers before it tells you anything. This one starts from the questions players actually ask:

Any brand, by gauge. Tension is a function of gauge, material, scale length and pitch — not the brand on the box. Pick the gauges and tuning and the result applies to whatever brand's set matches, accurate to within a pound or two.
It warns you when strings will flop. Drop tunings with light strings go slack and buzz. This is the only calculator that flags any string falling below a usable tension threshold, so you can size up before you order — see our starter electric guitar picks if you're still choosing the instrument too.
Edit any gauge live. Building a custom set? Change one string's gauge in the table and the tension and total update on the spot — no spreadsheet.
Honest, cited math. The formula and the D'Addario-sourced unit weights are on the page, and a fixture test checks the engine against D'Addario's own published set tensions on every build.

How it works (the physics)

String tension comes from one well-established formula. A string of a given mass-per-inch, stretched to a given length and vibrating at a given pitch, pulls a predictable force:

T = ( UW × (2 × L × F)² ) / 386.4

   T   = tension (pounds)
   UW  = unit weight of the string (pounds per inch)
   L   = scale length (inches)
   F   = pitch frequency (Hz) — e.g. low E = 82.41 Hz
   386.4 = gravity constant (in/s²) for imperial units

Two things drive the unit weight: the string's diameter and its construction. A plain steel string's weight is fixed by physics (weight rises with the square of the diameter). A wound string adds a winding around a steel core, so a nickel-wound electric string and a phosphor-bronze acoustic string of the same .026″ gauge weigh — and therefore pull — slightly different amounts. This calculator uses D'Addario's published unit weights for each construction, then plugs in your scale length and the frequency of each tuned note. Add up all six and you get the total pull on the neck.

Three setups worth understanding

10–46 in standard tuning, 25.5″ — the reference point

A regular-light electric set in standard tuning on a Fender-scale guitar lands around 106 lb total — the tension most players think of as "normal." It's the default this tool opens on, and a useful baseline to compare everything else against.

9–42 in Drop C — why it flops

Take a super-light set and tune way down to Drop C and the calculator lights up a floppy-string warning: the low strings fall under a usable tension and will rattle and choke. The fix the result suggests is heavier strings — which is exactly why drop-tuned players reach for thicker bottoms.

Baritone scale, 27″ — same pitch, more pull

Switch the scale length to 27″ and watch the total climb even though the tuning hasn't changed. That extra tension is what keeps a baritone or down-tuned guitar tight and articulate where a normal scale would go slack.

Frequently asked questions

What is a good total string tension for a guitar?

For a 6-string electric in standard tuning, most factory sets land between roughly 90 and 120 lb total, with 100–110 lb (a 10–46 set) being the comfortable middle. A 6-string acoustic pulls more — usually 150–190 lb — because the wound strings are heavier and tuned to the same pitches. There's no single "correct" number; it's about the feel you want and what your guitar is built for. Use the feel verdict as a guide, not a rule.

Does string tension change with tuning?

Yes — directly. Tension rises and falls with pitch, so tuning down (Drop D, E♭, Drop C) lowers tension and tuning up raises it. That's why down-tuned guitars often feel loose with normal strings, and why heavier gauges are the usual fix. This calculator recomputes the moment you change the tuning so you can see the exact effect.

How do I stop my strings feeling floppy in drop tunings?

Use heavier strings, a longer scale length, or both. Heavier wound strings carry more tension at the same low pitch, and a longer (baritone) scale adds tension without changing the note. Set your target tuning here, watch for the floppy-string warning, and bump the gauges until it clears — then learn a few chords in that tuning with strings that actually ring.

Is string tension the same for every brand?

Very nearly. Tension depends on gauge, material, scale length and pitch — not the logo. Two .010 plain steel strings, or two .046 nickel-wound strings, from different brands weigh almost the same and pull almost the same tension. Expect real-world differences of only about a pound or two from winding and batch variation, so these figures apply to whatever brand's set matches your gauges.

Will heavier strings damage my guitar?

A modest jump (say 9s to 10s, or 10s to 11s) is fine on virtually any guitar, though it can shift the action and intonation enough to want a quick setup. Large jumps — or putting heavy strings on a vintage or lightly-built acoustic — meaningfully raise total tension, so it's worth checking the total here first and having a tech adjust the truss rod if you're making a big change.

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Strings to dial in your feel

Once you know the tension you're aiming for, the right set is the one that hits it. The calculator suggests specific sets under your result based on the feel and any floppy-string flags — here's the logic:

Feels stiff? Drop a gauge. Lighter strings cut total tension for easier bends and faster fretting.
Strings flopping in a low tuning? Go heavier on the bottom — a heavy-bottom electric set or a medium acoustic set restores the tension a drop tuning takes away.
Just want balanced? A 10–46 electric or 12–53 acoustic set is the middle-of-the-road tension most players settle on. If you're picking your first instrument, our best beginner acoustic guitars guide pairs well with a light set.

Sources & methodology

Tension formula is the industry-standard T = UW × (2LF)² / 386.4, where UW is unit weight in lb/in, L is scale length in inches, and F is the pitch frequency in Hz.
Unit weights are D'Addario's published values: plain steel from the standard 0.2215 × d² relationship, nickel-wound (electric) and phosphor-bronze (acoustic) from D'Addario's string tension specifications.
Frequencies use equal temperament with A4 = 440 Hz. The engine is verified against D'Addario's own published set tensions (e.g. a 10–46 electric set ≈ 106 lb) by a fixture test that runs on every build.

Tensions are accurate planning figures, not lab measurements — real-world tension varies about a pound or two by brand, batch and exact winding. Feel/comfort bands are general guidance. Reviewed by Julian Reyes, MM (Berklee). About Julian · Last reviewed June 29, 2026.

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