Calibre vs. Gauge — What's the Difference?
By Tayyaba Rehman & Maham Liaqat — Updated on May 16, 2024
Calibre refers to the diameter of a firearm's barrel, while gauge measures the bore diameter of shotguns, with lower numbers indicating larger bores.
Difference Between Calibre and Gauge
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Key Differences
Calibre is primarily used to describe the diameter of a firearm's barrel or the diameter of the bullet that it fires. It is often expressed in millimeters or inches. Gauge, on the other hand, is used specifically for shotguns and is based on the weight of a lead ball that fits the bore.
Calibre provides a straightforward numerical measurement that directly corresponds to the size of the bullet or the barrel. Whereas, gauge uses an inverse relationship where smaller numbers indicate larger bores and larger numbers indicate smaller bores.
In terms of application, calibre is commonly used in handguns, rifles, and other firearms that fire single projectiles. Meanwhile, gauge is exclusively applied to shotguns, which fire a spread of shot or a single slug.
Calibre measurements can be more precise, allowing for exact calculations of bullet and barrel diameters. Conversely, gauge is a more traditional measurement system, reflecting historical methods of determining bore size through lead ball weight.
While calibre often aligns with ammunition naming conventions, gauge has unique terminologies like "12-gauge" or "20-gauge," which can be less intuitive than calibre designations.
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Comparison Chart
Definition
Diameter of a firearm's barrel or bullet
Bore size based on lead ball weight
Measurement Units
Inches or millimeters
Number of lead balls per pound
Application
Handguns, rifles, other firearms
Shotguns
Precision
High, exact measurement
Traditional, less intuitive
Ammunition Naming
Numerical (e.g., .45 calibre)
Specific terms (e.g., 12-gauge)
Compare with Definitions
Calibre
Diameter of a firearm's barrel.
The rifle has a calibre of 7.62 mm.
Gauge
Bore size of a shotgun.
He prefers using a 12-gauge shotgun for hunting.
Calibre
Size of a bullet.
A .22 calibre bullet is quite small.
Gauge
Traditional shotgun measurement.
Older shotguns are often classified by gauge.
Calibre
Standard for classifying firearms.
The handgun's calibre determines its range.
Gauge
An instrument that measures and gives a visual display of the amount, level, or contents of something
A fuel gauge
Calibre
Metric or imperial measurement.
The gun uses 9 mm calibre rounds.
Gauge
The thickness, size, or capacity of something, especially as a standard measure.
Calibre
Measurement unit for ammunition.
He bought .45 calibre ammunition.
Gauge
The position of a sailing ship to windward (the weather gage) or leeward (the lee gage) of another
The French fleet was heavily outnumbered but had the weather gage
Calibre
The quality of someone's character or the level of their ability
They could ill afford to lose a man of his calibre
Gauge
Estimate or determine the amount, level, or volume of
Astronomers can gauge the star's intrinsic brightness
Calibre
The internal diameter or bore of a gun barrel
A small-calibre revolver
Gauge
Measure the dimensions of (an object) with a gauge
When dry the assemblies can be gauged exactly
Calibre
Variant of caliber.
Gauge
The distance between the two rails of a railroad.
Calibre
A degree or grade of excellence or worth;
The quality of students has risen
An executive of low caliber
Gauge
The distance between two wheels on an axle.
Calibre
Diameter of a tube or gun barrel
Gauge
The interior diameter of a shotgun barrel as determined by the number of lead balls of a size exactly fitting the barrel that are required to make one pound. Often used in combination
A 12-gauge shotgun.
Gauge
The thickness or diameter of sheet metal, wire, or a similar manufactured material or piece.
Gauge
The fineness of knitted cloth as measured by the number of stitches per a given unit of length.
Gauge
A standard or scale of measurement
The capacity of barrels was measured according to the gauge in use at the time.
Gauge
An instrument for measuring the dimensions, capacity, or amount of something
A pressure gauge.
A fuel gauge.
Gauge
A means of estimating or evaluating; a test
A gauge of character.
Gauge
(Nautical) The position of a vessel in relation to another vessel and the wind.
Gauge
To measure the dimensions, capacity, proportions, or amount of (something), especially by means of a gauge
Gauged the thickness of the metal part.
Gauge
To evaluate or estimate
Gauge a person's interest.
Gauge
To adapt or make conform to a specified standard
Pressure valves that are gauged to industry requirements.
Gauge
To chip or rub (bricks or stones) to size.
Gauge
To stretch (a pierced earlobe or other body part) by inserting progressively larger objects over a long period of time.
Gauge
Of or relating to a gauge.
Gauge
(Physics) Invariant under a local transformation.
Gauge
A measure; a standard of measure; an instrument to determine dimensions, distance, or capacity; a standard
Gauge
An act of measuring.
Gauge
An estimate.
Gauge
Any instrument for ascertaining or regulating the level, state, dimensions or forms of things
Gauge
A thickness of sheet metal or wire designated by any of several numbering schemes.
Gauge
(rail) track gauge
Gauge
(rail) loading gauge
Gauge
A semi-norm; a function that assigns a non-negative size to all vectors in a vector space.
Gauge
(knitting) The number of stitches per inch, centimetre, or other unit of distance.
Gauge
(nautical) Relative positions of two or more vessels with reference to the wind.
A vessel has the weather gauge of another when on the windward side of it, and the lee gauge when on the lee side of it.
Gauge
(nautical) The depth to which a vessel sinks in the water.
Gauge
(plastering) The quantity of plaster of Paris used with common plaster to make it set more quickly.
Gauge
That part of a shingle, slate, or tile, which is exposed to the weather, when laid; also, one course of such shingles, slates, or tiles.
Gauge
(firearms) A unit of measurement which describes how many spheres of bore diameter of a shotgun can be had from one pound of lead; 12 gauge is roughly equivalent to .75 caliber.
Gauge
A shotgun (synecdoche for 12 gauge shotgun, the most common chambering for combat and hunting shotguns).
Gauge
A tunnel-like ear piercing consisting of a hollow ring embedded in the lobe.
Gauge
Cannabis.
Gauge
(transitive) To measure or determine with a gauge; to measure the capacity of.
Gauge
(transitive) To estimate.
Gauge
(transitive) To appraise the character or ability of; to judge of.
Gauge
To draw into equidistant gathers by running a thread through it.
Gauge
(transitive) To mix (a quantity of ordinary plaster) with a quantity of plaster of Paris.
Gauge
(transitive) To chip, hew or polish (stones, bricks, etc) to a standard size and/or shape.
Gauge
To measure or determine with a gauge.
Gauge
To measure or to ascertain the contents or the capacity of, as of a pipe, barrel, or keg.
Gauge
To measure the dimensions of, or to test the accuracy of the form of, as of a part of a gunlock.
The vanes nicely gauged on each side.
Gauge
To draw into equidistant gathers by running a thread through it, as cloth or a garment.
Gauge
To measure the capacity, character, or ability of; to estimate; to judge of.
You shall not gauge meBy what we do to-night.
Gauge
A measure; a standard of measure; an instrument to determine dimensions, distance, or capacity; a standard.
This plate must be a gauge to file your worm and groove to equal breadth by.
There is not in our hands any fixed gauge of minds.
Gauge
Measure; dimensions; estimate.
The gauge and dimensions of misery, depression, and contempt.
Gauge
Any instrument for ascertaining or regulating the dimensions or forms of things; a templet or template; as, a button maker's gauge.
Gauge
Any instrument or apparatus for measuring the state of a phenomenon, or for ascertaining its numerical elements at any moment; - usually applied to some particular instrument; as, a rain gauge; a steam gauge.
Gauge
Relative positions of two or more vessels with reference to the wind; as, a vessel has the weather gauge of another when on the windward side of it, and the lee gauge when on the lee side of it.
Gauge
The distance between the rails of a railway.
Gauge
The quantity of plaster of Paris used with common plaster to accelerate its setting.
Gauge
That part of a shingle, slate, or tile, which is exposed to the weather, when laid; also, one course of such shingles, slates, or tiles.
Gauge
A measuring instrument for measuring and indicating a quantity such as the thickness of wire or the amount of rain etc.
Gauge
Accepted or approved instance or example of a quantity or quality against which others are judged or measured or compared
Gauge
The distance between the rails of a railway or between the wheels of a train
Gauge
The thickness of wire
Gauge
Diameter of a tube or gun barrel
Gauge
Judge tentatively or form an estimate of (quantities or time);
I estimate this chicken to weigh three pounds
Gauge
Rub to a uniform size;
Gauge bricks
Gauge
Determine the capacity, volume, or contents of by measurement and calculation;
Gauge the wine barrels
Gauge
Measure precisely and against a standard;
The wire is gauged
Gauge
Adapt to a specified measurement;
Gauge the instruments
Gauge
Mix in specific proportions;
Gauge plaster
Gauge
Number of lead balls fitting the bore per pound.
A 20-gauge means 20 balls weigh one pound.
Gauge
Indirect size indicator.
Lower gauge numbers mean larger bores.
Gauge
Specific to shotguns.
The 16-gauge shotgun is less common now.
Common Curiosities
What does gauge measure?
Gauge measures the bore size of a shotgun based on the weight of lead balls.
Can calibre and gauge be used interchangeably?
No, calibre is for firearms' barrel/bullet diameter, while gauge is for shotguns' bore size.
What is the primary use of calibre?
Calibre is used to measure the diameter of a firearm's barrel or bullet.
What calibre is commonly used for rifles?
Common rifle calibres include .223, .308, and 7.62 mm.
How is calibre expressed?
Calibre is expressed in inches or millimeters.
What does a 12-gauge shotgun mean?
A 12-gauge shotgun has a bore that fits a lead ball weighing 1/12 of a pound.
Is gauge specific to shotguns?
Yes, gauge is exclusively used for shotguns.
How does gauge relate to shotgun ammunition?
Gauge determines the size of the shotgun shell that fits the bore.
Are gauge numbers intuitive?
Gauge numbers can be less intuitive compared to calibre measurements.
Which is more precise, calibre or gauge?
Calibre is more precise with exact measurements, whereas gauge is a traditional system.
Is calibre used in metric or imperial units?
Calibre can be used in both metric (millimeters) and imperial (inches) units.
Is calibre relevant for shotguns?
No, shotguns are classified by gauge, not calibre.
Do smaller gauge numbers indicate larger or smaller bores?
Smaller gauge numbers indicate larger bores.
What is a common calibre for handguns?
Common handgun calibres include .45 ACP and 9 mm.
What does a 20-gauge shotgun indicate?
A 20-gauge shotgun has a smaller bore than a 12-gauge.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Maham Liaqat
