Gauges · tunings · scale length
String tension calculator.
See how hard each string pulls in any tuning, at any A4 and scale length, and which gauges keep the feel you like.
String tension · your setup
E Standard on a 10–46 set: the tuning this set is made for, about 103 lb in total.
E2 A2 D3 G3 B3 E4
Use 300–600 Hz. Esc puts the last value back.
Shared with the tuner and the tone generator.
Use 10–40″, or cm or mm like 64.8 cm or 648. Esc puts the last value back.
Change any gauge in the table to try your own set.
| String | Note | Gauge | Tension | Feel | vs standard | Same feel as standard |
|---|---|---|---|---|---|---|
| 6 | E282.41 Hz | 17.2 lb7.8 kg | Normal | 0% | ≈ 46 · same | |
| 5 | A2110.00 Hz | 19.1 lb8.7 kg | Normal | 0% | ≈ 36 · same | |
| 4 | D3146.83 Hz | 18.2 lb8.3 kg | Normal | 0% | ≈ 26 · same | |
| 3 | G3196.00 Hz | 16.6 lb7.5 kg | Normal | 0% | ≈ 17 · same | |
| 2 | B3246.94 Hz | 15.4 lb7.0 kg | Normal | 0% | ≈ 13 · same | |
| 1 | E4329.63 Hz | 16.2 lb7.4 kg | Normal | 0% | ≈ 10 · same | |
| Total | 10–46 | 102.7 lb46.6 kg | 0% | ≈ 10–46 |
Gauges from 5 to 200: 46, .046 or 46w (w = wound, p = plain). Esc puts the last value back.
Approximate: ±2–3% vs makers' charts; brands differ. The feel words are a rough guide: many players like their strings looser or tighter.
The formula
How string tension works
Every string pulls on the neck with a force set by three things: how heavy the string is, how long it vibrates, and how high it is tuned. The calculator uses the formula string makers publish:
T = UW · (2 · L · f)² / 386.088For a regular 10–46 electric set in E Standard on a 25.5″ scale that gives about 103 lb (47 kg) in total, with each string pulling between 15.4 and 19.1 lb.
What the letters mean
- T is the tension in pounds (lb). One pound is 0.4536 kg, or 4.448 newtons (N).
- UW is the unit weight: the mass of one inch of string, in pounds. For plain steel it follows from the density of steel; for wound strings it comes from smooth fits to published maker data.
- L is the scale length in inches, from the nut to the saddle.
- f is the frequency of the open string in Hz. It follows your tuning and your A4.
- 386.088 is gravity in inches per second squared. It turns pounds of mass into pounds of force.
Half steps
Tuning down: 2N/6
Tension grows with the square of the frequency. One half step down divides the frequency by 21/12, so it divides the tension by 21/6: about 11% less. After N half steps down, 2−N/6 of the tension is left, so two whole steps take away about 37%. To win the feel back, a string needs to be about 2N/12 times thicker (a little less for wound strings, which get heavier faster than their diameter).
| Half steps down | Tension | Gauge for the same feel | 10–46 becomes |
|---|---|---|---|
| 1 | −11% | ×1.06 | 10.5–49 |
| 2 | −21% | ×1.12 | 11–52 |
| 3 | −29% | ×1.19 | 12–54 |
| 4 | −37% | ×1.26 | 13–59 |
| 5 | −44% | ×1.33 | 13.5–62 |
| 7 | −55% | ×1.50 | 15–70 |
| 12 | −75% | ×2.00 | 20–93.5 |
Longer neck, more pull
Scale length
Tension also grows with the square of the scale length. The same strings at the same pitch pull harder on a longer neck, which is why baritone guitars use necks of 27″ to 30″, and why a set feels slinkier on a 24.75″ guitar than on a 25.5″ one.
| Scale | In cm | Tension | Like |
|---|---|---|---|
| 24.75″ | 62.9 cm | −5.8% | −0.5 half steps |
| 25″ | 63.5 cm | −3.9% | −0.3 half steps |
| 25.5″ | 64.8 cm | 0% | the reference |
| 26.5″ | 67.3 cm | +8.0% | +0.7 half steps |
| 27″ | 68.6 cm | +12.1% | +1.0 half steps |
| 28″ | 71.1 cm | +20.6% | +1.6 half steps |
| 28.6″ | 72.6 cm | +25.8% | +2.0 half steps |
| 30″ | 76.2 cm | +38.4% | +2.8 half steps |
Popular tunings
A 10–46 set in popular tunings
| Tuning | lb | kg | vs E Standard | Same feel |
|---|---|---|---|---|
| E Standard | 102.7 | 46.6 | 0% | made for it |
| E♭ Standard | 91.5 | 41.5 | −11% | ≈ 10.5–49 |
| Drop D | 99.2 | 45.0 | −3% | ≈ 10–52 |
| D Standard | 81.5 | 37.0 | −21% | ≈ 11–52 |
| Drop C | 78.7 | 35.7 | −23% | ≈ 11–59 |
| C Standard | 64.7 | 29.4 | −37% | ≈ 13–59 |
| Drop B | 70.1 | 31.8 | −32% | ≈ 12–62 |
| B Standard | 57.7 | 26.2 | −44% | ≈ 13.5–62 |
Feel
What the feel words mean
The bar for each string shows where its tension sits. These bands are rough, in pounds per string, and only a guide: jazz players often like heavy, tight strings, and many blues players like them loose.
| Instrument | Slack | Light | Normal | Firm | Tight |
|---|---|---|---|---|---|
| Electric guitar | under 12 | 12–14 | 14–20 | 20–24 | over 24 |
| Acoustic guitar | under 18 | 18–22 | 22–32 | 32–38 | over 38 |
| 12-string guitar | under 11.5 | 11.5–15.5 | 15.5–28 | 28–33 | over 33 |
| Bass guitar | under 25 | 25–30 | 30–45 | 45–52 | over 52 |
Accuracy
How accurate is it?
Plain steel strings are calculated from the density of steel and land within about half a percent of makers' charts. Wound strings depend on the core, the wrap and the maker, so they come from fits to published data: expect ±2–3% against a maker's chart, and a few percent between brands at the same gauge. The calculator models plain steel, nickel wound (electric), phosphor bronze (acoustic and 12-string) and nickel roundwound bass strings.
Ready to tune? Every tuning has its own tuner page, and the online tuner can shift any tuning by half steps.
Questions
How much tension is on a guitar?
About 103 lb (47 kg) with a regular 10–46 electric set in E Standard on a 25.5″ scale, roughly 15 to 19 lb per string. A 12–53 acoustic set pulls about 161 lb, a 4-string bass with 45–105 on 34″ about 173 lb, and a 12-string about 251 lb.
Do I need heavier strings when I tune down?
Not for a half step: most players keep their set. Each half step takes about 11% of the tension off, so from about two whole steps down (C Standard, 37% less) strings start to feel loose and buzz. To keep the feel of a 10–46 set in C Standard, try about 13–59.
Does scale length change string tension?
Yes, with the square of the length. The same strings at the same pitch have about 6% more tension on a 25.5″ neck than on a 24.75″ one, and a 27″ neck adds about 12% more again: close to tuning up a half step.