Electric Bass String Gauges Explained
Updated Nov 11, 2026 · By 
Jonah Mercer · Editorial policy
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Electric bass string gauges are the thickness figures printed on a set, and they tell you how thick each string is. A set marked 50-105 lists four strings at .050, .070, .085 and .105, and a set marked 45-100 starts at .045. The four sets here are 4-string sets in 45-100 and 50-105.
What the numbers on a string set mean
A gauge figure is the thickness of one string, so a larger figure is a thicker string and a smaller figure is a thinner string. A set name joins the thinnest and thickest figures with a dash: 50-105 runs from .050 to .105, and 45-100 runs from .045. Read the set name before you buy, and match its figures to the strings you want on the bass.
How to read the four gauges in a set
A 4-string set lists four figures, one for each string, running from the thinnest string to the thickest. The Ernie Ball Regular Slinky 50-105 set lists .050, .070, .085 and .105, with one figure for each of its four strings. Check the full list of four figures on the set, not only the figures in the set name, before you choose.
The 45-100 and 50-105 sets here
The sets here come in 45-100 and 50-105. The Ernie Ball Regular Slinky and the D'Addario NYXL are 50-105 sets, and the Ernie Ball Super Slinky and the D'Addario XL are 45-100 sets. The Ernie Ball sets are nickel wound, and the D'Addario sets are nickel-plated steel. Match the set name to the gauge size you want, and check the material in the set name before you buy.
When to change a set of bass strings
Change the strings when they show signs of wear, not on a fixed schedule. Look for strings that are discolored or rough to the touch, rust on the wrap wire, or strings that no longer hold tune. How much and where you play changes how fast the signs appear, so check the strings each time you pick up the bass.
What you need
Ernie Ball Regular Slinky Nickel Wound Bass
A 50-105 nickel wound 4-string set that lists each string at .050, .070, .085 and .105, with Element Shield Packaging that prolongs string life.
- Material: Nickel Wound
Ernie Ball Super Slinky Nickel Wound Bass
A 45-100 nickel wound 4-string set, the lighter Ernie Ball gauge set here, with Element Shield Packaging that prolongs string life.
- Material: Nickel Wound
D'Addario XL Nickel Bass Guitar Strings 45-100
A 45-100 nickel-plated steel 4-string set with a Hex-Core, in the lighter gauge size here.
- Material: Nickel-Plated Steel
D'Addario NYXL Bass Guitar Strings 50-105
A 50-105 nickel-plated steel 4-string set with an NY Steel core wire and a reengineered core-to-wrap ratio.
- Material: Nickel-Plated Steel
These come from our ranked list Best Bass Guitar Strings, which compares them spec by spec.
Frequently asked questions
What do 45-100 and 50-105 mean on a bass string set?
The figures name the thinnest and thickest strings in the set. The 50-105 set lists .050, .070, .085 and .105, and the 45-100 set starts at .045.
How do I know when to change bass strings?
Look for strings that are discolored or rough to the touch, rust on the wrap wire, or strings that no longer hold tune. How much and where you play changes how fast the signs appear.
What is the difference between the D'Addario XL and NYXL sets?
The XL set is built on a Hex-Core, and the NYXL set uses an NY Steel core wire with a reengineered core-to-wrap ratio. The XL set is a 45-100 set, and the NYXL set is a 50-105 set.
Ranked guitar strings lists
More how-to guides
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