Free Guitar String Tension Calculator
Calculate tension per string and total for any gauge, scale, and tuning.
What is a guitar string tension calculator?
A guitar string tension calculator is a free online tool that helps you compute string tension for any gauge, scale length, and tuning to find the right setup for your guitar. It runs entirely in your browser — no signup, no app, and no data is ever sent to a server.
A guitar string tension calculator tells you the exact tension of each string based on three variables: gauge, scale length, and tuning. String tension determines how your guitar feels — too low and strings buzz and feel floppy; too high and they're stiff and hard to bend. The calculator works for any 6-string tuning and gauge set, from standard EADGBE to drop C or open G.
How it works
The calculator uses the standard string tension formula T = (UW × (2LF)²) ÷ 386.4. For each string, it determines the frequency from the tuning note, the unit weight from the gauge, and applies the scale length. The result shows individual string tension and the total. Most players aim for 90-110 lbs total tension for a balanced feel.
When to use a string tension calculator
Any time you're changing tunings — going from standard to drop tuning reduces tension significantly. When choosing new string gauges for your specific guitar. When comparing different scale lengths (Strat vs Les Paul vs baritone). When you want to match the feel of one guitar's string tension on another guitar with a different scale length.
Common mistakes with string tension
The mistake I see most often is assuming feel comes from gauge alone. A set of 10-46 strings on a 24.75-inch Les Paul feels noticeably looser than the same set on a 25.5-inch Strat — the scale length difference accounts for about 15% tension variation. Players switching from a Gibson to a Fender often say strings feel stiff when really the longer scale is pulling them to higher tension. The fix is dropping one gauge step when moving to a longer scale, not changing your tuning preference.
Another common error is ignoring unit weight differences between string brands. Nickel-wound and pure nickel strings of the same gauge have different unit weights, and coated strings can vary by 5-10%. If you switch from D'Addario XL to Elixir Nanoweb, you might feel a tension difference even though the gauge number on the pack is identical. The calculator accounts for material-specific unit weights for accurate tension numbers regardless of brand.
I also find many guitarists overlook overall tension balance when mixing tunings. A standard set tuned to drop D might feel fine on low strings but overly tight on high strings. The calculator shows per-string tension so you can mix gauges — a common setup for drop C is 10-52, using heavier low strings to compensate for looser tuning while keeping high strings comfortable.
How to use this calculator
- Enter your scale length — Standard electric is 25.5" (Fender) or 24.75" (Gibson). Acoustic is typically 25.4".
- Enter string gauges — Enter the gauge (diameter in thousandths of an inch) for each string.
- Enter tuning frequencies — Select standard, drop, or custom tuning. The calculator computes tension per string and total.
Frequently asked questions
How do I calculate guitar string tension?
String tension depends on three factors: gauge (diameter), scale length, and pitch (tuning). The formula is T = (UW × (2 × L × F)²) ÷ 386.4, where UW is the unit weight of the string, L is scale length, and F is frequency. Higher tuning, heavier gauge, and longer scale all increase tension.
What string tension is standard for electric guitar?
Most electric guitar players use 9-42 or 10-46 gauge strings in standard tuning on a 25.5-inch scale. Total tension is typically 90-110 lbs. Lighter strings (8-38) have about 75-85 lbs total tension. Heavier strings (11-50) have 110-135 lbs. The 'feel' of string tension is subjective, but most players prefer 90-110 lbs.
How does drop tuning affect string tension?
Dropping a string reduces its tension. Dropping E to D on a 25.5-inch scale reduces that string's tension from about 17 lbs to 13.5 lbs (25% less). That's why players often use heavier gauge strings for drop tuning — to restore the tension to a comfortable level. Drop C typically uses 11-54 or 12-56 sets.
What scale length increases tension the most?
Longer scale lengths increase tension. A 25.5-inch (Fender) scale has about 15% higher tension per string than a 24.75-inch (Gibson) scale with the same gauge and tuning. Baritone guitars (27-30 inch scale) can have very high tension — players often use lighter gauges to compensate.
Can I use bass or 7-string gauges in this calculator?
The calculator supports any gauge value you enter, but the unit weight formula is calibrated for standard 6-string guitar string materials. Bass strings use different core and wrap ratios. For 7-string or 8-string guitars, the calculator still works — just enter all gauges in order from low to high and the tension formula applies correctly.
Why does drop tuning require heavier gauge strings?
Dropping the tuning of a string lowers its pitch, which directly reduces tension. The low E string at standard tuning has about 17 lbs of tension on a 25.5-inch scale. Dropping it to D reduces tension to about 13.5 lbs — a 25% drop. To restore the feel, you increase the gauge: a 0.052 gauge string at D gives roughly the same tension as a 0.046 at E.