Convert Micrometers (Ra) to Microinches (Ra)
Instantly convert Micrometers (Ra) (μm) to Microinches (Ra) (μin) with our free online calculator.
Formula: μm to μin — multiply by 39.3701
Reference Table
| Micrometers (Ra) (μm) | Microinches (Ra) (μin) |
|---|---|
| 1 | 39.3701 |
| 5 | 196.85 |
| 10 | 393.701 |
| 25 | 984.252 |
| 50 | 1968.5 |
| 100 | 3937.01 |
How to Convert Micrometers (Ra) to Microinches (Ra)
Formula
To convert Micrometers (Ra) (μm) to Microinches (Ra) (μin): multiply by 39.3701
Step-by-Step
- Start with your value in Micrometers (Ra) (μm).
- Multiply by 39.3701 to perform the conversion.
- The result is your value expressed in Microinches (Ra) (μin).
Conversion Factor
1 μm = 39.3701 μin
Reverse Factor
1 μin = 0.0254 μm
Worked Example
Convert 25 Micrometers (Ra) to Microinches (Ra): 25 μm = 984.252 μin
About Micrometer (Ra) (μm)
The SI unit of surface roughness — most commonly reported as the arithmetic mean deviation Ra in micrometers (μm). μm Ra is the global manufacturing standard for specifying surface finish on machine drawings. Typical values: machined 1.6–6.3 μm; ground 0.2–1.6 μm; lapped/polished < 0.1 μm. ISO 1302 and ISO 21920 require μm Ra on drawings.
About Microinch (Ra) (μin)
An imperial surface-roughness unit equal to 0.0254 μm. Microinches (μin) are the traditional US unit on machining drawings — typical values: machined 63–250 μin; ground 8–63 μin; mirror 4 μin or less. Converting μin to μm (÷39.37) is a routine step when US parts are manufactured overseas.
Quick Facts
- 1 Micrometer (Ra) equals 39.3701 Microinches (Ra)
- 1 Microinch (Ra) equals 0.0254 Micrometers (Ra)
- Micrometer (Ra) is a unit of surface roughness
- Microinch (Ra) is a unit of surface roughness
- This conversion is commonly used in machining, quality control, and tribology
- The Micrometer (Ra) belongs to the metric system
- The Microinch (Ra) belongs to the imperial system
Common Micrometer (Ra) to Microinch (Ra) Conversions
| Micrometers (Ra) (μm) | Microinches (Ra) (μin) |
|---|---|
| 0.01 | 0.393701 |
| 0.1 | 3.93701 |
| 0.25 | 9.84252 |
| 0.5 | 19.685 |
| 1 | 39.3701 |
| 2 | 78.7402 |
| 3 | 118.11 |
| 5 | 196.85 |
| 10 | 393.701 |
| 15 | 590.551 |
| 20 | 787.402 |
| 25 | 984.252 |
| 50 | 1968.5 |
| 75 | 2952.76 |
| 100 | 3937.01 |
| 250 | 9842.52 |
| 500 | 19685 |
| 1000 | 39370.1 |
| 5000 | 196850 |
| 10000 | 393701 |
Understanding Micrometers (Ra)
The Micrometer (Ra) (symbol: μm) is a unit of surface roughness. The SI unit of surface roughness — most commonly reported as the arithmetic mean deviation Ra in micrometers (μm). μm Ra is the global manufacturing standard for specifying surface finish on machine drawings. Typical values: machined 1.6–6.3 μm; ground 0.2–1.6 μm; lapped/polished < 0.1 μm. ISO 1302 and ISO 21920 require μm Ra on drawings.
It belongs to the metric measurement system.
Micrometers (Ra) are commonly used in machining, quality control, and tribology.
Understanding Microinches (Ra)
The Microinch (Ra) (symbol: μin) is a unit of surface roughness. An imperial surface-roughness unit equal to 0.0254 μm. Microinches (μin) are the traditional US unit on machining drawings — typical values: machined 63–250 μin; ground 8–63 μin; mirror 4 μin or less. Converting μin to μm (÷39.37) is a routine step when US parts are manufactured overseas.
It belongs to the imperial measurement system.
Microinches (Ra) are commonly used in machining, quality control, and tribology.
Why Convert Micrometers (Ra) to Microinches (Ra)?
Converting between Micrometers (Ra) and Microinches (Ra) is a frequent requirement for engineers, scientists, and students working with surface roughness values. Different industries and regions favour different unit systems, so having a dependable conversion tool saves time and prevents errors in technical calculations. Whether you are verifying a specification sheet, cross-checking simulation results, or preparing a report for an international audience, accurate surface roughness conversion is essential.
Frequently Asked Questions
How do I convert Micrometers (Ra) to Microinches (Ra)?
The SI unit of surface roughness — most commonly reported as the arithmetic mean deviation Ra in micrometers (μm). To convert Micrometers (Ra) to Microinches (Ra), multiply by 39.3701. For example, 25 μm equals 984.252 μin.
How many Microinches (Ra) are in 1 Micrometer (Ra)?
There are 39.3701 Microinches (Ra) in 1 Micrometer (Ra).
How many Micrometers (Ra) are in 1 Microinch (Ra)?
There are 0.0254 Micrometers (Ra) in 1 Microinch (Ra).
What is the formula for Micrometer (Ra) to Microinch (Ra) conversion?
The formula is: multiply by 39.3701. This means 1 μm = 39.3701 μin.
Is a Micrometer (Ra) bigger than a Microinch (Ra)?
No. One Micrometer (Ra) is smaller than one Microinch (Ra) because 1 μm equals 39.3701 μin, which is greater than 1.
When do you need to convert between Micrometers (Ra) and Microinches (Ra)?
An imperial surface-roughness unit equal to 0. Micrometer (Ra) and Microinch (Ra) are both surface roughness units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.