Convert Perch to Microinch
Convert perches to microinches instantly. 1 perch = 1.98e+8 microinch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Microinch to Perch converter for the reverse conversion.
Units explained
Perch
A perch is an Imperial unit of length identical to the rod — 16.5 feet (about 5.03 m). The names 'rod', 'perch', and 'pole' all refer to the same surveying unit and differ only by regional preference.
Like the rod, the perch derives from medieval English land-surveying. The name 'perch' was particularly common in legal land descriptions in Ireland and parts of the UK.
Perches appear in legacy land descriptions in Ireland, the UK, and historical US documents. Modern usage is rare.
Medieval English surveying origin; identical to the rod since 1620; became exact via the 1959 International Yard and Pound Agreement.
Microinch
A microinch is an Imperial unit of length equal to one millionth of an inch (2.54×10⁻⁸ m). It is used almost exclusively in surface-finish specifications for precision machining and optical components.
The microinch is derived from the inch using the SI-style prefix micro- to denote one millionth. Standardised through the 1959 International Yard and Pound Agreement, which fixed the inch at exactly 25.4 mm.
Microinches express surface roughness (Ra values) in US-based precision manufacturing — typical machined surfaces are 16–125 µin. Optical components and bearing races are often specified to 1–4 µin Ra.
Used in US precision-manufacturing literature throughout the 20th century; value became exact in 1959 when the inch was fixed at 25.4 mm via the International Yard and Pound Agreement.
Perch to Microinch conversion formula
The relationship between perches and microinches:
To convert perches to microinches, multiply the value in perches by 1.98e+8. To reverse, multiply microinches by 5.050505e-9.
How to use this converter
Type a value into the calculator. The result in microinches updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Microinch to Perch converter for the reverse direction.
Step-by-step: convert perches to microinches
- Write down the value in perches (perch).
- Multiply that value by the factor 1.98e+8.
- The product is the equivalent value in microinches (µin).
- To reverse, multiply the microinch value by 5.050505e-9.
Worked examples
Example 1 — Convert 1 perch to µin:
1 × 1.98e+8 = 1.98e+8 µin
Example 2 — Convert 100 perch to µin:
100 × 1.98e+8 = 1.98e+10 µin
Real-world example — Meter to nanoscale
One perch equals one billion microinches. Physics curricula use this conversion to teach orders of magnitude when introducing the electromagnetic spectrum.
1 perch × 1.98e+8 = 1.98e+8 µin
Real-world example — Human-scale to atomic dimensions
One perch equals one billion microinches — the canonical metric conversion bridging everyday objects and atomic-scale features in physics, chemistry, and electronics.
1 perch × 1.98e+8 = 1.98e+8 µin
Perch to Microinch conversion table
Standard reference values for converting perches to microinches:
| Perch [perch] | Microinch [µin] |
|---|---|
| 0.01 | 1980000.0000000002 |
| 0.1 | 1.98e+7 |
| 1 | 1.98e+8 |
| 2 | 3.96e+8 |
| 3 | 5.94e+8 |
| 4 | 7.92e+8 |
| 5 | 9.9e+8 |
| 10 | 1.98e+9 |
| 20 | 3.96e+9 |
| 30 | 5.94e+9 |
| 40 | 7.92e+9 |
| 50 | 9.9e+9 |
| 100 | 1.98e+10 |
| 500 | 9.9e+10 |
| 1000 | 1.98e+11 |
Frequently asked questions
How many microinches is 1 perch?
How do I convert perches to microinches?
How do I convert microinches back to perches?
How many microinches is 100 perches?
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Imperial / US Customary (26 units)
Sources & references
Conversion factor (1 perch = 1.98e+8 µin) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.