What is micrometre?
A micrometre, also called a micron, is a unit of length equal to one millionth of a metre. It is used in microscopy, semiconductor fabrication, and the measurement of fine particles and biological cells.
Real-world uses
Micrometres (microns) are used to measure biological cells, bacteria, semiconductor chip features, and fine particle sizes in air quality monitoring. Paint film thickness, fibre diameters, and precision machining tolerances are also specified in µm.
History
The micrometre was formalized with SI prefix standardization in the 20th century. The term "micron" was officially revoked by the SI in 1967 in favour of "micrometre," though "micron" persists informally in many industries.
Common mistakes
Using the symbol "u" instead of the correct "µ" (Greek mu). Also, confusing micrometres with nanometres—a human hair is about 70 µm wide, not 70 nm.
What is centimetre?
A centimetre is a metric unit of length equal to one hundredth of a metre. It is commonly used for everyday measurements such as clothing sizes, body height, and small object dimensions.
Real-world uses
Centimetres are widely used in clothing measurements, body height in medical records (outside the US), screen sizes in some markets, and school rulers. Tailors and dressmakers rely on centimetre tape measures for precise garment fitting.
History
The centimetre was established as part of the original metric system in the 1790s. It served as the base length unit in the now-superseded CGS (centimetre-gram-second) system used extensively in physics until the mid-20th century.
Common mistakes
Forgetting that there are 2.54 cm in one inch, not 2.5. Also, confusing cm² (area) with cm (length) when specifying material dimensions.
When is this conversion used?
Screen sizes, paper dimensions, and clothing measurements often require converting between centimetres and inches, especially when shopping internationally.
Worked examples
1 micrometre = 0.0001 centimetre
1 centimetre = 0.01 metre
How to convert micrometre to centimetre
To convert micrometre to centimetre, multiply the value by 0.0001.
To convert centimetre back to micrometre, multiply by 10,000.
Measurement standards
The metre is one of seven SI base units, maintained by the International Bureau of Weights and Measures (BIPM). Since 2019, it is defined by fixing the numerical value of the speed of light in vacuum to exactly 299,792,458 metres per second.
Did you know?
A human hair is roughly 70 micrometres wide, while a single gold atom measures about 0.144 nanometres in diameter — meaning you could line up nearly half a million atoms across the width of one hair.
Quick reference: micrometre to centimetre
| micrometre | centimetre |
|---|---|
| 0.1 | 0.00001 |
| 0.5 | 0.00005 |
| 1 | 0.0001 |
| 2 | 0.0002 |
| 5 | 0.0005 |
| 10 | 0.001 |
| 25 | 0.0025 |
| 50 | 0.005 |
| 100 | 0.01 |
| 250 | 0.025 |
| 500 | 0.05 |
| 1,000 | 0.1 |
Common values
| micrometre | centimetre | |
|---|---|---|
| Height of a door | 2,100,000 micrometre | 210 centimetre |
| Basketball court length | 28,000,000 micrometre | 2,800 centimetre |
| Football field (soccer) | 105,000,000 micrometre | 10,500 centimetre |
| Marathon distance | 4.219500e+10 micrometre | 4,219,500 centimetre |
| Altitude of a cruising airplane | 1.066800e+10 micrometre | 1,066,800 centimetre |