Guitar String Tension Calculator
This guitar string tension calculator will help you choose strings for your guitar while keeping string tension in mind. Knowing some basic guitar string tension physics can help you learn how to calculate guitar string tension, understand your instrument more, and create a more comfortable playing experience, suitable for beginners.
In this calculator, you will learn:
- How to calculate guitar string tension;
- Some basic guitar string tension physics - the factors in tuning a guitar;
- What the guitar string tension formula is; and
- Some basic information about balanced tension guitar strings.
Ready to learn how much tension is on your guitar strings? Then, let's get started.
Guitar string tension
The guitar string tension is one of these three factors that influence the frequency of a guitar string, along with the string gauge and guitar's scale length. Thinner strings weigh less and can vibrate faster than thicker strings, resulting in higher-pitch sounds. Guitar strings are available in gauges as thin as 0.007th of an inch to as thick as 0.08th of an inch.
We can purchase guitar strings in materials like steel, nickel, copper, and nylon. We quantify their weight using linear density, also commonly called unit weight. We usually express this measurement in
pounds per inch or
kilograms per meter. Thicker strings require more tension or a heavier pull to achieve their required tuning.
Now, let's look at the guitar's scale length. The scale length is the length of the open string between the guitar's nut and bridge, and is the length over which the string vibrates to produce a sound. A long scale length would require more tension to pull a string tight to meet its desired pitch. The same string would require less tension to be tuned to that same pitch if it was placed on a shorter scale length.
Applying more tension to a particular string gauge than it's meant to handle would produce a higher pitch, and may cause it to snap. Applying less tension results in a looser string which produces a lower pitch. Sometimes, however, even at the correct tension, it feels hard to press the string down the guitar's fingerboard, even resulting in discomfort or pain.
Through experience, you will learn which string gauges feel okay to you while you play. You can then use that as a reference when choosing replacement strings for your guitar. To get the right strings for you, we need to learn some guitar string tension physics. That is where our guitar string tension calculator comes in handy.
How do you measure guitar string tension using our calculator?
With our guitar string tension calculator, you will find the tension through a particular guitar string. Once you know that string's tension, you can use that as a reference when choosing a string gauge for your other strings. Here are the steps you can follow when using our calculator:
- Enter your guitar's scale length.
- Select the pitch of your string to match your preferred tuning.
- Choose the string type and string gauge you want to use. Doing so will display the required tension for this string.
As an added feature to this tool, you can also use our guitar string tension calculator as a guitar string unit weight calculator. Simply repeat these same steps and replace the estimated tension with your desired guitar string tension. Our tool will then recalculate the recommended unit weight for that tension and frequency. This is perfect if you already know how a particular string tension feels to your finger.
Guitar string tension formula: The physics behind guitar string tension
In this section, you will learn how to measure the guitar string tension using this very simple guitar string tension formula derived from the wavelength formula:
T = (f * 2 * L) ² * μ / g
T - Guitar string tension;
f - Frequency the string vibrates at;
L - Scale length;
μ - Linear density or unit weight of the string; and
g - Gravitational acceleration.
Naturally, we measure tension in units such as pound-force or Newtons and don't have the gravitational acceleration in the formula. But, in some cases (like in the string tension of a bowstring or tennis racquet strings), we express tension in terms of mass. In the next section, let's use this formula to find how much tension is on a guitar string.
Example of how to calculate guitar string tension
Let's say we want to determine the tension needed to pull a 0.010-gauge pure steel string, with a unit weight of
0.00002215 lb/in, to tune it to E4 on a
25.5-inch scale length guitar. Ideally, E4 vibrates at a rate of
329.6 Hz. Using our guitar string tension formula, we now have:
T = (f * 2 * L) ² * μ / g
T = (329.6 Hz * 2 * 25.5 in) ² * 0.00002215 lb/in / 386.08858 in/s²
T = 16.2106912 lb ≈ 16.2 lb
With our guitar string tension calculator, you can now try out different string gauges for your other strings and try to get values close to 16.2 lb. That will ensure you have balanced tension guitar strings. Typically guitar strings are available in sets that result in a variety of string tensions, but some stores sell balanced tension guitar strings if that's what you want.
Want to learn more?
If you found this interesting and would like to learn more about guitar physics, you can check out our fret calculator. There you will learn how to calculate the placement of frets and how its formula is derived.
How do I know my guitar string tension?
To calculate how much tension is on a guitar string:
- Measure your guitar's scale length in inches.
- Multiply this length by 2 and multiply the product by the frequency you want to this string to vibrate at.
- Square this value and multiply it by the unit weight of your guitar string in pounds per inch. Your guitar string's unit weight is usually indicated on its packaging.
- Finally, divide everything by 386.09 lb/in² to find the tension in pounds.
How do I reduce string tension in a guitar?
To reduce the string tension in guitar, you can:
- Replace your current strings with a lighter or thinner gauge guitar string set.
- Tune your guitar a note or half a note down. You would have to transpose your chords to play your music in its original key.
- You can also transfer your guitar strings to a shorter guitar to relieve some string tension.
How much tension is on each string of a guitar?
Each guitar string usually differs from the other but ranges between 16 to 20 pounds on a 25.5-inch scale length guitar at standard tuning for medium-weight guitar strings. However, this range increases for guitars with longer scale lengths and decreases for shorter scale lengths. Heavier and lighter guitar strings also increase and decrease the required string tension, respectively.
How do I calculate the tension in the E string of my 25.5-inch guitar?
To find the tension in your guitar's E string;
- Double your guitar's scale length: 25.5 × 2 = 51 inches.
- Multiply 51 inches by 329.6 Hz, which is E4's frequency: 51 × 329.6 = 16,809.6 in/s.
- Square this value and multiply it by the unit weight of your guitar string in pounds per inch. Let's say that its packaging indicates it has 0.00002215 lb/in-unit weight: (16,809.6)² × 0.00002215 = 6258.76 lb (force).
- Divide this by 386.09 lb/in² to find the tension in pounds: 6258.75 / 386.9 = 16.2 lb.
What are balanced-tension guitar strings?
Balanced-tension guitar strings are a set of carefully selected guitar strings of different gauges, which result in relatively even tension when set in a particular tuning. What balanced tension does is it makes playing the guitar easier, especially for beginners. It is also best used when playing bar chords, where you use your index finger to press on multiple strings simultaneously.