Microinches Conversion

Select the unit you wish to convert to




Unit of:


Wordwide use:

Microinches are a unit of measurement commonly used in engineering and manufacturing industries worldwide. Despite the metric system being the predominant system of measurement in most countries, microinches are still widely used due to their precision and accuracy in measuring surface finishes and tolerances.

Microinches are particularly useful in industries that require extremely fine measurements, such as aerospace, automotive, and electronics. They provide a more detailed and precise measurement than other units, allowing engineers and manufacturers to ensure the quality and functionality of their products. Microinches are commonly used to measure surface roughness, flatness, and the thickness of coatings or films.

Although the metric system offers alternative units for measuring surface finishes, such as micrometers (µm) or nanometers (nm), microinches remain popular due to their historical usage and familiarity in the industry. Additionally, many older machines and tools are calibrated in microinches, making it more convenient to continue using this unit rather than converting to metric units.


Microinches is a unit of measurement used to express extremely small distances or surface roughness. It is derived from the inch, which is a commonly used unit in the United States and a few other countries. The prefix "micro" indicates that the measurement is one millionth of an inch, making it a highly precise unit. 1 in = 1,000,000 μin

Microinches are often used in industries that require precise measurements, such as engineering, manufacturing, and machining. They are particularly useful for measuring surface finishes, where even the smallest imperfections can have a significant impact on the performance of a product. For example, in the automotive industry, microinches are used to measure the smoothness of engine components, ensuring optimal performance and reducing friction.

To put the size of a microinch into perspective, it is approximately 25 times smaller than a micron, which is already a very small unit of measurement. To convert from microinches to other units, such as millimeters or microns, it is necessary to divide the measurement by 39.37 or 25.4, respectively.


The origin of microinches as a unit of measurement can be traced back to the need for a more precise measurement in certain industries, particularly in manufacturing and engineering. The term "microinch" is derived from the combination of the prefix "micro-" which denotes one millionth, and the unit of length "inch". Microinches are used to measure extremely small distances or surface finishes that cannot be accurately measured in inches or millimeters. This unit is commonly employed in industries such as aerospace, automotive, and electronics, where precision is crucial.

The concept of microinches gained popularity in the mid-20th century when advancements in technology and manufacturing processes required more precise measurements. It provided a way to express measurements in smaller increments than traditional units like inches or millimeters.

Common references:

1 million (1,000,000) microinches = 1 inch

Usage context:

Microinches is a unit of measurement commonly used in engineering and manufacturing industries, particularly in the United States. It is a subunit of an inch, with one microinch equal to one millionth of an inch. The usage of microinches is primarily seen in precision measurements where extremely small tolerances are required. One of the main applications of microinches is in the measurement of surface roughness. In industries such as automotive, aerospace, and electronics, the smoothness of surfaces is crucial for optimal performance. Microinches provide a precise and standardized unit to quantify the roughness of a surface, allowing engineers to ensure that the desired level of smoothness is achieved during manufacturing processes.

Another context where microinches are commonly used is in the measurement of tolerances for machined parts. In manufacturing, it is essential to maintain tight tolerances to ensure the proper functioning and interchangeability of components. Microinches provide a finer level of measurement compared to other units, allowing engineers to specify and control tolerances with greater accuracy. This is particularly important in industries such as medical devices, where even the smallest deviations can have significant consequences.


Popular links