Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Amperes to Milliamperes
Convert A to mA instantly, then review the formula, assumptions, and rounding guidance.
Electrical unitsInstant result
Decimals
Formula result = input × 1 ÷ 0.001. 1 A = 1,000 mA
Common examples
One value, several units
Milliamperes1,000 mA
Kiloamperes0.001 kA
Microamperes1,000,000 µA
Conversion table
| A | mA |
|---|---|
| 1 A | 1,000 mA |
| 2 A | 2,000 mA |
| 5 A | 5,000 mA |
| 10 A | 10,000 mA |
| 25 A | 25,000 mA |
| 50 A | 50,000 mA |
| 100 A | 100,000 mA |
Conversion chart
1 A1,000 mA
5 A5,000 mA
10 A10,000 mA
25 A25,000 mA
50 A50,000 mA
Worked example
1 ampere equals 1,000 milliamperes.
Unit definition
Amperes (A) One amperes equals 1 ampere.
Unit history
Amperes is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert A to ampere.
3. Convert the base value to mA and apply your display precision.
Understand the result before using it
Amperes to Milliamperes converts a value measured in Amperes (A) into the equivalent value in Milliamperes (mA). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 1 ÷ 0.001
Assumptions
- Amperes and Milliamperes represent the same current quantity.
- The input is expressed in A; the output is expressed in mA.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 A = 1,000 mA. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a A measurement in a document that expects mA.
- Compare a amperes value with a value reported in milliamperes.
- Check the A-to-mA arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- Do not confuse A with another unit that has a similar name or symbol.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Amperes to Milliamperes?
result = input × 1 ÷ 0.001 Using the displayed relationship, 1 A equals 1,000 mA.
How many Milliamperes are in one Amperes?
One Amperes is 1,000 Milliamperes. The displayed digits may be rounded.
Can I reverse the A to mA conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts mA back to A.
Is the Amperes to Milliamperes result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.