Micrometer to Ell Converter
Convert micrometers to ells with our free online length converter.
Quick Answer
1 Micrometer = 8.748906e-7 ells
Formula: Micrometer × conversion factor = Ell
Use the calculator below for instant, accurate conversions.
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All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Micrometer to Ell Calculator
How to Use the Micrometer to Ell Calculator:
- Enter the value you want to convert in the 'From' field (Micrometer).
- The converted value in Ell will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Length category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Micrometer to Ell: Step-by-Step Guide
Converting Micrometer to Ell involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Micrometer = 8.7489e-7 ellsExample Calculation:
Convert 10 micrometers: 10 × 8.7489e-7 = 8.7489e-6 ells
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
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Need to convert to other length units?
View all Length conversions →What is a Micrometer and a Ell?
A micrometer is a unit of length in the metric system equal to one millionth (1/1,000,000) of a meter. The term derives from the Greek "mikros" (small) and "metron" (measure). It is abbreviated as μm, where μ (mu) is the Greek letter representing the prefix "micro-."
Note on terminology: While "micron" was widely used from 1879 to 1967, it was officially deprecated by the International System of Units (SI) in favor of "micrometer" to maintain consistent naming conventions. However, "micron" remains common in some industries, particularly semiconductor manufacturing and filtration.
The micrometer sits between the millimeter and nanometer on the metric scale:
- 1 meter = 1,000,000 micrometers
- 1 millimeter = 1,000 micrometers
- 1 micrometer = 1,000 nanometers
This scale makes micrometers perfect for measuring objects visible under optical microscopes but invisible to the naked eye.
Convert Micrometers to Other Units →
The Ell is an historical unit of length, primarily used for measuring cloth and textiles. Its exact length varied considerably depending on the region, country, and time period, making it a non-standardized unit overall, though often legally defined within specific jurisdictions.
It is generally understood to have originated from the length of the arm or forearm, similar to the cubit. The name itself derives from the Proto-Germanic word *alinō, meaning "forearm".
Common historical values demonstrate this variability:
- English Ell: Traditionally 45 inches (1.25 yards, exactly 1.143 meters). This was the most common ell in England, particularly for measuring imported Flemish cloth.
- Scottish Ell: Approximately 37.06 inches (about 0.941 meters), based on the standard Scottish inch.
- Flemish (or Brabant) Ell: Approximately 27 inches (about 0.686 meters). Widely used in the Low Countries, a major center for textile production.
- French Ell (Aune): Varied, but often around 46.77 inches (about 1.188 meters) in Paris. The aune itself had different lengths in different French regions.
- Polish Ell (Łokieć): Approximately 22.7 inches (about 0.576 meters).
- Swedish Ell (Aln): Approximately 23.3 inches (about 0.593 meters).
Note: The Micrometer is part of the metric (SI) system, primarily used globally in science and trade. The Ell belongs to the imperial/US customary system.
History of the Micrometer and Ell
The concept of the micrometer emerged alongside the development of precision microscopy in the 17th and 18th centuries. As scientists like Robert Hooke and Antonie van Leeuwenhoek observed cells and microorganisms for the first time, they needed standardized ways to describe these microscopic dimensions.
The term "micron" (μ) was officially adopted at the First International Electrical Congress in Paris in 1879 as a convenient shorthand for one millionth of a meter. This simplified notation became widely used in scientific literature, particularly in biology, materials science, and optics.
In 1960, the International System of Units (SI) was established to create consistent naming conventions across all units. By 1967-1968, the SI officially deprecated "micron" in favor of "micrometer" to align with the systematic naming structure where prefixes like "micro-," "nano-," and "kilo-" are clearly indicated.
Despite this official change, the term "micron" persists in several industries:
- Semiconductor manufacturing: Process nodes like "5-micron technology"
- Filtration systems: "10-micron water filter"
- Materials science: Particle size specifications
- Aerospace: Surface finish requirements
The symbol μm is universally recognized in scientific and technical documentation, combining the Greek letter μ (representing the micro- prefix meaning 10⁻⁶) with m for meter.
Today, micrometers are fundamental to numerous high-precision fields, from medical diagnostics and semiconductor fabrication to quality control and environmental monitoring.
The ell was a fundamental unit for the textile trade across Europe, flourishing from the medieval period through the early modern era and into the 19th century. Its origins likely lie in anthropomorphic measurements related to the arm, similar to the cubit.
The lack of a universal standard led to numerous regional variations. Different cities, guilds, or nations established their own "standard" ell, often physically represented by a metal rod kept by authorities. This variation could sometimes be a source of trade disputes but also reflected local manufacturing and trade practices.
The English ell of 45 inches (longer than the standard English yard of 36 inches) became particularly well-established, possibly to account for shrinkage or to provide a customary "bonus" measure when selling cloth.
With the rise of standardized measurement systems like the Imperial system (promoting the yard) and especially the Metric system (introducing the meter), the ell gradually became obsolete during the 18th and 19th centuries. Legal reforms in many countries formally abolished it in favor of metric units.
Common Uses and Applications: micrometers vs ells
Explore the typical applications for both Micrometer (metric) and Ell (imperial/US) to understand their common contexts.
Common Uses for micrometers
1. Microscopy and Biology
Micrometers are the standard unit for measuring cells, bacteria, and other microorganisms under optical microscopes. Lab technicians and researchers use calibrated eyepiece scales marked in micrometers to measure biological specimens. Cell biology, microbiology, and histology all depend on micrometer measurements for specimen identification and analysis.
2. Semiconductor Manufacturing
The semiconductor industry uses micrometers (often called "microns") to specify process node sizes, though modern chips have moved to nanometer scales. Wafer thickness (typically 725 μm for 300mm wafers), photoresist layers, and older chip features are measured in micrometers. Quality control requires precise measurements to ensure manufacturing tolerances.
3. Precision Engineering
Manufacturing engineers specify tolerances in micrometers for high-precision components. CNC machining, grinding, and polishing operations achieve accuracies of ±1-10 μm. Measuring instruments like micrometers (the tool) can measure to 0.001 mm = 1 μm precision. Critical aerospace, medical device, and automotive components require micrometer-level quality control.
4. Fiber Optics and Telecommunications
Fiber optic cables have core diameters measured in micrometers: single-mode fibers typically use 8-10 μm cores, while multi-mode fibers range from 50-62.5 μm. The precise core diameter determines light transmission characteristics, bandwidth, and distance capabilities. Telecom technicians reference these specifications when installing and troubleshooting fiber networks.
5. Filtration and Air Quality
Filter manufacturers rate products by the size of particles they capture, measured in micrometers. HEPA filters capture 99.97% of particles ≥0.3 μm. Water filters, air purifiers, and industrial filtration systems all use micrometer ratings. Environmental agencies track PM2.5 (particulate matter <2.5 μm) and PM10 pollution, which pose respiratory health risks.
6. Medical Diagnostics
Medical laboratories measure blood cells in micrometers: red blood cells average 6-8 μm, while variations may indicate conditions like anemia. Pathologists examine tissue samples and tumor margins at micrometer scale. Medical device manufacturing (catheters, needles, implants) requires micrometer-precision specifications for safety and efficacy.
Convert Medical Measurements →
7. Surface Finish and Coatings
Surface roughness is measured in micrometers using parameters like Ra (average roughness). A mirror finish might be <0.1 μm Ra, while machined surfaces range from 0.8-25 μm Ra. Coating thickness—paint, anodizing, plating—is specified in micrometers to ensure corrosion protection and aesthetic quality.
When to Use ells
The ell is now obsolete but was historically crucial for:
- Textile Trade: Its primary and defining use was measuring and selling lengths of cloth (wool, linen, silk, etc.). Cloth was often priced and sold "by the ell".
- Tailoring and Dressmaking: Used by artisans creating garments.
- Mercantile Records: Appears frequently in historical merchant accounts, inventories, customs documents, and trade records. Understanding the local ell is vital for interpreting these economic historical sources.
- Land Measurement (Rarely): In some specific, localized contexts, an ell might have been used for land, but this was uncommon compared to units like the rod or chain.
- Literature and Culture: Referenced in historical texts, literature, and idioms (e.g., "Give him an inch, and he'll take an ell").
Additional Unit Information
About Micrometer (μm)
Is a micrometer the same as a micron?
Yes, micrometer and micron refer to the same unit: one millionth of a meter (1×10⁻⁶ m or 1 μm). The term "micron" (symbol: μ) was officially used from 1879 to 1967 but was deprecated by the International System of Units (SI) in favor of "micrometer" to maintain consistent naming conventions.
Despite being officially deprecated, "micron" remains common in several industries:
- Semiconductor manufacturing ("5-micron process")
- Filtration ("10-micron filter")
- Materials science (particle size specifications)
In scientific and technical writing, "micrometer" (μm) is the preferred term, but both are universally understood.
How many micrometers are in a millimeter?
There are 1,000 micrometers (μm) in 1 millimeter (mm). This makes sense when you consider the metric prefixes:
- "Milli-" means one thousandth (1/1,000)
- "Micro-" means one millionth (1/1,000,000)
Since a micrometer is 1,000 times smaller than a millimeter, dividing 1 mm into 1,000 equal parts gives you 1 μm per part.
Examples:
- 0.5 mm = 500 μm
- 0.1 mm = 100 μm
- 0.075 mm = 75 μm (typical human hair)
Convert Millimeters to Micrometers →
What are some examples of things measured in micrometers?
Biological:
- Bacteria: 1-10 μm (E. coli ≈ 2 μm)
- Red blood cells: 6-8 μm
- Human hair diameter: 50-100 μm
- Pollen grains: 10-100 μm
Technology:
- Fiber optic core: 8-62.5 μm (depending on type)
- Semiconductor features: 0.01-10 μm (older processes)
- Surface roughness: 0.1-25 μm (machining)
Materials:
- Paint thickness: 25-100 μm
- Plastic wrap: 10-15 μm
- Paper thickness: 70-100 μm
Essentially, anything visible under an optical microscope but invisible to the naked eye is measured in micrometers.
How do I convert micrometers to inches?
To convert micrometers to inches, multiply by 0.00003937 (or divide by 25,400).
Formula: inches = micrometers × 0.00003937
Examples:
- 100 μm × 0.00003937 = 0.003937 inches (≈ 0.004")
- 1,000 μm × 0.00003937 = 0.03937 inches (≈ 0.04")
- 2,540 μm × 0.00003937 = 0.1 inches
For context, 1 inch = 25,400 μm (or 25.4 mm), so micrometers are extremely small when expressed in imperial units.
Convert Micrometers to Inches →
Can the human eye see micrometers?
The human eye's resolution limit is approximately 50-100 micrometers under ideal conditions. This means:
Barely visible (with perfect vision):
- Thick human hair: 100 μm
- Fine sand grains: 100-500 μm
- Large dust particles: 100+ μm
Invisible without magnification:
- Bacteria: 1-10 μm
- Red blood cells: 6-8 μm
- Fine dust: <50 μm
- Most microorganisms: <50 μm
To see objects smaller than ~50 μm, you need a microscope. Optical microscopes can resolve features down to about 0.2 μm (200 nm), while electron microscopes can see structures at the nanometer scale.
What is the difference between micrometer and nanometer?
A micrometer (μm) equals one millionth of a meter (10⁻⁶ m), while a nanometer (nm) equals one billionth of a meter (10⁻⁹ m). This means 1 micrometer = 1,000 nanometers.
Scale comparison:
- Micrometer scale: bacteria, cells, human hair (1-100 μm)
- Nanometer scale: viruses, molecules, atoms (1-100 nm)
Examples:
- Red blood cell: 7,000 nm = 7 μm
- Coronavirus particle: 100 nm = 0.1 μm
- DNA helix width: 2 nm = 0.002 μm
- Silicon atom: 0.2 nm = 0.0002 μm
Optical microscopes work at the micrometer scale, while electron microscopes are needed for nanometer-scale imaging.
Convert Micrometers to Nanometers →
How accurate are micrometer measuring tools?
A micrometer (the measuring instrument, also called a "mike") typically measures with an accuracy of ±0.001 mm (±1 μm) for standard models, and ±0.0001 mm (±0.1 μm) for digital precision models.
Types and accuracy:
- Standard mechanical: ±0.001 mm (±1 μm)
- Vernier micrometer: ±0.001 mm (±1 μm)
- Digital micrometer: ±0.0005-0.001 mm (±0.5-1 μm)
- High-precision digital: ±0.0001 mm (±0.1 μm)
Accuracy depends on:
- Tool quality and calibration
- Temperature (thermal expansion affects readings)
- Operator technique (proper force and reading)
- Workpiece surface condition
For even higher precision, coordinate measuring machines (CMMs) and optical comparators can achieve sub-micrometer accuracy in controlled environments.
Why was "micron" deprecated?
The International System of Units (SI) deprecated "micron" in 1967-1968 to maintain consistent naming conventions across all metric units. The SI system uses standard prefixes (micro-, nano-, kilo-, etc.) combined with base units (meter, gram, second) to create derived units.
Reasons for change:
- Consistency: "Micrometer" follows the pattern of millimeter, nanometer, kilometer
- Clarity: Combines "micro-" (10⁻⁶) with "meter" to clearly indicate the scale
- International standardization: Reduces confusion in scientific communication
- Symbol standardization: μm is unambiguous, while μ alone could be confused with other uses
Why "micron" persists:
- Shorter and easier to say ("micron" vs "micrometer")
- Decades of industry usage before 1967
- Well-established in semiconductor, filtration, and materials industries
- No confusion in context (everyone knows what "10-micron filter" means)
In formal scientific writing, use "micrometer (μm)" for SI compliance.
What equipment measures in micrometers?
Precision measuring instruments:
- Micrometer caliper (the tool): Measures dimensions to ±1 μm accuracy
- Dial indicator: Measures displacement to ±1-5 μm
- Coordinate Measuring Machine (CMM): Sub-micrometer accuracy
- Optical comparator: Projects magnified image for micrometer-scale inspection
- Laser interferometer: Measures to nanometer/sub-micrometer accuracy
Microscopy equipment:
- Optical microscope: With calibrated eyepiece scales (reticles) marked in micrometers
- Confocal microscope: 3D imaging with micrometer resolution
- Scanning Electron Microscope (SEM): Nanometer resolution but calibrated in micrometers
Surface analysis:
- Surface roughness tester (profilometer): Measures Ra, Rz in micrometers
- Thickness gauge: Coating thickness to ±1 μm
- Film thickness measurement: Non-contact optical methods
Quality control:
- Particle size analyzers: Measure suspended particles in micrometers
- Laser diffraction instruments: Characterize powders and emulsions
How is micrometer used in air quality standards?
Air quality standards use micrometers to classify particulate matter (PM) by size, which determines health impacts:
PM10 (Particulate Matter <10 μm):
- Includes dust, pollen, mold
- Can reach lungs but often trapped in nose/throat
- EPA 24-hour standard: 150 μg/m³
PM2.5 (Particulate Matter <2.5 μm):
- Includes combustion particles, smoke, fine dust
- Small enough to enter deep into lungs and bloodstream
- EPA 24-hour standard: 35 μg/m³
- More dangerous than PM10 due to deep lung penetration
Why size matters:
- >10 μm: Trapped in nose and throat
- 2.5-10 μm: Can reach upper respiratory tract and lungs
- <2.5 μm: Can penetrate deep into lungs and enter bloodstream
- <0.1 μm (ultrafine): Can cross into organs and brain
Filter effectiveness:
- HEPA filters: Capture 99.97% of particles ≥0.3 μm
- N95 masks: Filter 95% of particles ≥0.3 μm
- Standard HVAC filters: Typically 3-10 μm particle capture
Understanding micrometer-scale particle sizes is critical for respiratory health, especially for vulnerable populations.
Convert Air Quality Measurements →
About Ell (ell)
How long is an Ell?
There is no single fixed length for the ell; it varied significantly by location and time. Some key examples include:
- English Ell: 45 inches (1.143 m)
- Scottish Ell: ~37 inches (~0.94 m)
- Flemish Ell: ~27 inches (~0.69 m)
- French Aune (Ell): ~47 inches (~1.19 m) Always check the context (region and era) when encountering a measurement in ells. The English ell of 45 inches is often assumed in English-language historical contexts unless otherwise specified.
How does the Ell compare to a Yard?
The English ell (45 inches) is exactly 1.25 times longer than the standard yard (36 inches). However, other ells could be shorter (like the Flemish ell) or have different relationships to the local yard equivalent.
Is the Ell related to the Elbow or Arm?
Yes, the name "ell" derives from Proto-Germanic *alinō ("forearm"), cognate with Latin ulna and Greek ōlénē, all referring to the forearm or elbow. This strongly suggests an origin based on the length of the human arm, similar to the cubit. However, the standardized lengths adopted for trade were often considerably longer than a literal forearm.
Why did the Ell length vary so much?
The variation stemmed from:
- Lack of Universal Standards: Before the metric system, measurement standards were highly localized.
- Regional Customs: Different areas developed their own traditional lengths based on local needs and practices.
- Trade Protectionism: Sometimes, variations were maintained deliberately by guilds or cities.
- Evolution Over Time: The definition could change even within the same region over centuries.
Is the Ell an SI unit?
No, the ell is not part of the International System of Units (SI). It is an historical, customary unit belonging to various pre-metric systems. The corresponding SI unit for length is the meter (m).
Is the Ell still used today?
No, the ell is obsolete and is not used for any standard commercial, scientific, or practical measurements today. Its use was superseded primarily by the yard (in Imperial/US customary systems) and the meter (in the metric system). Its relevance is now purely historical.
Conversion Table: Micrometer to Ell
| Micrometer (μm) | Ell (ell) |
|---|---|
| 0.5 | 0 |
| 1 | 0 |
| 1.5 | 0 |
| 2 | 0 |
| 5 | 0 |
| 10 | 0 |
| 25 | 0 |
| 50 | 0 |
| 100 | 0 |
| 250 | 0 |
| 500 | 0 |
| 1,000 | 0.001 |
People Also Ask
How do I convert Micrometer to Ell?
To convert Micrometer to Ell, enter the value in Micrometer in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our length converter page to convert between other units in this category.
Learn more →What is the conversion factor from Micrometer to Ell?
The conversion factor depends on the specific relationship between Micrometer and Ell. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Ell back to Micrometer?
Yes! You can easily convert Ell back to Micrometer by using the swap button (⇌) in the calculator above, or by visiting our Ell to Micrometer converter page. You can also explore other length conversions on our category page.
Learn more →What are common uses for Micrometer and Ell?
Micrometer and Ell are both standard units used in length measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our length converter for more conversion options.
For more length conversion questions, visit our FAQ page or explore our conversion guides.
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⚖️ Metric vs Imperial
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Other Length Units and Conversions
Explore other length units and their conversion options:
- Meter (m) • Micrometer to Meter
- Kilometer (km) • Micrometer to Kilometer
- Hectometer (hm) • Micrometer to Hectometer
- Decimeter (dm) • Micrometer to Decimeter
- Centimeter (cm) • Micrometer to Centimeter
- Millimeter (mm) • Micrometer to Millimeter
- Inch (in) • Micrometer to Inch
- Foot (ft) • Micrometer to Foot
- Yard (yd) • Micrometer to Yard
- Mile (mi) • Micrometer to Mile
Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Official US standards for length measurements
Bureau International des Poids et Mesures — International System of Units official documentation
Last verified: December 3, 2025