Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Unit Converters
SI Ampere Prefix Converter (nA, µA, mA, A, kA)
to = from × 10^(fromExp − toExp) on amperes.
LED strings in milliamps, lab picoammeters, and utility kiloamperes share one ampere. A 20 mA loop is 0.02 A. Fuses are labeled in the prefix the catalog bought, not the one your meter displays.
amperes · 420 prefix pairs
amperes
0.02 A
Multiply by 10^-3. Same dimension; only the zeros move.
- You entered
- 20 mA
- Factor
- 10^-3
- In scientific notation
- 2.000000e-2
Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
From prefix
The “From prefix” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
LED strings in milliamps, lab picoammeters, and utility kiloamperes share one ampere. A 20 mA loop is 0.02 A. Fuses are labeled in the prefix the catalog bought, not the one your meter displays. to = from × 10^(fromExp − toExp) on amperes. Example: 20 mA → 0.02 A → 20,000 µA. A 200 A welder is 0.2 kA.
to = from × 10^(fromExp − toExp) on amperes.
Example: 20 mA → 0.02 A → 20,000 µA. A 200 A welder is 0.2 kA.
When to use this SI Ampere Prefix
Common use cases
- LED strings in milliamps, lab picoammeters, and utility kiloamperes share one ampere. A 20 mA loop is 0.02 A. Fuses are labeled in the prefix the catalog bought, not the one your meter displays.
- Sanity-check with this case: 20 mA → 0.02 A → 20,000 µA. A 200 A welder is 0.2 kA.
- The relationship is: to = from × 10^(fromExp − toExp) on amperes.
Localized examples
- Unit Converters: the example on this page uses the same formula as the widget.
What you get
- Fields: From prefix
- to = from × 10^(fromExp − toExp) on amperes.
- Example on the page: 20 mA → 0.02 A → 20,000 µA. A 200 A welder is 0.2 kA.
How to Convert SI Ampere Prefix Step-by-Step
- 1Enter From prefix. Use the values you have, not a catalog average, unless that is all you know.
- 2to = from × 10^(fromExp − toExp) on amperes.
- 3Worked case: 20 mA → 0.02 A → 20,000 µA. A 200 A welder is 0.2 kA.
- 4Check which dictionary the other person is using — US or UK, decimal or 1,024 — then trust the number.
Governing formula
to = from × 10^(fromExp − toExp) on amperes.
20 mA → 0.02 A → 20,000 µA. A 200 A welder is 0.2 kA.
Example: set From prefix = 20, then read the result.
Variable definitions
- value
From prefix
The “From prefix” field. Default 20; typical range 0–1e+24.
- The conversion (to = from × 10^(fromExp − toExp) on amperes.) does not pick US vs UK gallons, SI vs binary megabytes, or Mach at altitude for you. Read the footnote on the page.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Milliamp-hours are charge. This page scales current only.
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- SI Gram Prefix ConverterMass prefixes attach to the gram, not the kilogram. Kilogram is already kilo + gram. Scale yottagram down to yoctogram, or milligram to microgram, without mixing in pounds. Jewelry carats and troy ounces are separate legal pages.
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- SI Joule Prefix ConverterFood calories (thermochemical) are 4.184 J. Nutrition labels in kJ. Explosives data in MJ and GJ. Same joule. kWh and BTU are other dictionaries with their own pages.
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4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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