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Micron vs. Micrometer — What's the Difference?

By Tayyaba Rehman — Updated on September 7, 2023
A micron is a unit of length equal to one millionth of a meter. A micrometer is both a unit of length identical to a micron and an instrument used to measure small dimensions.
Micron vs. Micrometer — What's the Difference?

Difference Between Micron and Micrometer


Key Differences

A micron is simply a unit of measurement in the metric system. Micrometers, on the other hand, serve a dual role: they are both a unit of length equivalent to a micron and a precision instrument used for measurement.
The word micron originates from the Greek word "mikros," which means small. Micrometer has a more technical origin, borrowing the "micro-" prefix for smallness and adding "-meter," signifying it as an instrument for measuring.
In everyday language, the term micron is used almost exclusively to describe a unit of length. Micrometer is usually used in the context of the measuring instrument when spoken by the general public. However, in scientific contexts, both terms can refer to the unit of length.
In terms of spelling, micron is a simpler term, consisting of six letters. Micrometer is longer and can be broken down into "micro-" and "-meter," revealing its function as a measuring tool. Yet, both are often abbreviated: micron as "µ" and micrometer as either "µm" for the unit of length or as "micrometer" for the instrument.

Comparison Chart


Unit of length
Unit of length and measuring instrument


Greek "mikros"
Combines "micro-" and "-meter"

Common Usage

Unit of length
Both unit of length and measuring instrument


Shorter, 6 letters
Longer, 10 letters


"µm" for unit, "micrometer" for instrument

Compare with Definitions


A unit of length equivalent to one-millionth of a meter.
The bacterium was just a few microns long.


A precision instrument for measuring small dimensions, typically in the micron range.
She used a micrometer to measure the thickness of the metal sheet.


A metric unit for measuring small distances.
The thickness of the paper is about 100 microns.


A device featuring a calibrated screw used for precise measurements.
The engineer carefully turned the micrometer's screw to get an accurate reading.


A term used in microscopy for detailing the size of microscopic entities.
The cell has a diameter of 20 microns.


A unit of length that is equal to one-millionth of a meter.
The micrometer is a standard unit for measuring the thickness of biological cells.


A unit used in scientific contexts to express wavelengths, particle sizes, and other microscopic scales.
The wavelength of this light is 500 microns.


An instrument commonly used in mechanical engineering and material science for measuring thickness.
The micrometer provided the exact dimensions needed for the mechanical drawing.


A standard for particle size in air filters and other sieving mechanisms.
The air filter captures particles as small as 0.3 microns.


A gauge that can measure dimensions down to fractions of a millimeter.
The micrometer showed that the gap was less than half a millimeter wide.


A unit of length equal to one millionth of a metre, used in many technological and scientific fields.


A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for accurate measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers. Micrometers are usually, but not always, in the form of calipers (opposing ends joined by a frame).


A unit of length equal to one thousandth (10-3) of a millimeter or one millionth (10-6) of a meter. Also called micrometer.


A gauge that measures small distances or thicknesses between its two faces, one of which can be moved away from or towards the other by turning a screw with a fine thread.


(physics) The thousandth part of one millimeter; the millionth part of a meter.


US spelling of micrometre


(figurative) A very tiny amount.


A device for measuring very small distances, objects, or angles, especially one based on the rotation of a finely threaded screw.


(linguistics) breve


See micron.


A measure of length; the thousandth part of one millimeter; the millionth part of a meter.


A device used to measure distance very precisely but within a limited range, especially depth, thickness, and diameter.


A metric unit of length equal to one millionth of a meter


Alternative spelling of micrometre


An instrument, used with a telescope or microscope, for measuring minute distances, or the apparent diameters of objects which subtend minute angles. The measurement given directly is that of the image of the object formed at the focus of the object glass.


Caliper for measuring small distances


A metric unit of length equal to one millionth of a meter

Common Curiosities

Can micron and micrometer be used interchangeably?

As a unit of length, yes. But remember, micrometer also refers to a measuring instrument.

What is a micron?

A micron is a unit of length equal to one-millionth of a meter.

What is a micrometer?

A micrometer is both a unit of length identical to a micron and an instrument for measuring small dimensions.

Is a micron smaller than a millimeter?

Yes, a micron is much smaller than a millimeter.

What is a micron commonly used to measure?

It is used to measure things like cell sizes, wavelengths, and particle sizes.

How do you abbreviate micrometer?

For the unit of length, it's "µm"; for the instrument, it's "micrometer."

What do people commonly measure with a micrometer instrument?

Typically dimensions of mechanical parts, material thickness, and other small distances.

What is the origin of the word micron?

It comes from the Greek word "mikros," meaning small.

What professions commonly use micrometers?

Engineers, scientists, and machinists commonly use micrometers.

How many microns are in a millimeter?

There are 1,000 microns in a millimeter.

What's the abbreviation for micron?

The abbreviation is "µ."

Do both micron and micrometer have a plural form?

Yes, the plural of micron is microns, and the plural of micrometer is micrometers.

What is the origin of the word micrometer?

It combines "micro-" for small and "-meter" for measuring.

Is a micron visible to the naked eye?

No, it is too small to be seen without a microscope.

Is a micrometer more precise than a ruler?

Yes, a micrometer is designed for very precise measurements.

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Author Spotlight

Written by
Tayyaba Rehman
Tayyaba Rehman is a distinguished writer, currently serving as a primary contributor to 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.

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