Ampere is the SI unit of electric current.
Amperes to Milliamperes Converter — A to mA
Convert Ampere (A) to Milliampere (mA) using the exact conversion factor (1 ampere = 1,000 milliampere). See the formula, worked examples, conversion table, history, and common uses.
Amperes to Milliamperes converter
Converter
Electricity Converter
Convert electrical units by family and calculate voltage, current, resistance, power, and energy with context values.
Context values
Some unit families need one extra value for a physically accurate result.
Milliampere is 0.001 ampere units.
Result = input x 1 / 0.001.
Electrical units in the same family convert directly.
Reserved above the conversion cards and below the converter.
About Converting Amperes to Milliamperes
Ampere and Milliampere both belong to the electricity family — voltage, current, resistance, power, or energy — units that show up constantly when working across the different standards used by household wiring (120V/240V depending on region), automotive electrical systems (12V/24V), and electronics design. Ampere is most often used for electrical circuit design and fuse/breaker ratings.
Formula
milliamperes = amperes × 1000
This factor comes from each unit's defined relationship to the category's base unit: 1 ampere equals 1 base unit, and 1 milliampere equals 0.001 base units, so dividing one by the other gives the direct ampere-to-milliampere factor of 1000.
Simple example
1 A × 1000 = 1,000 mA
1 ampere = 1,000 milliamperes.
Real-world example
120 A × 1000 = 120,000 mA
120 amperes = 120,000 milliamperes.
Conversion table
| Ampere (A) | Milliampere (mA) |
|---|---|
| 1 A | 1,000 mA |
| 5 A | 5,000 mA |
| 12 A | 12,000 mA |
| 24 A | 24,000 mA |
| 120 A | 120,000 mA |
| 240 A | 240,000 mA |
Reverse conversion: Milliampere to Ampere
1 mA × 0.001 = 0.001 A
1 milliampere = 0.001 amperes.
amperes = milliamperes × 0.001
For a page dedicated to this direction, see Milliampere to Ampere.
Understanding the Ampere
Ampere (A) measures electric current. The SI base unit of electric current. It is classified as a SI base unit.
Where it's used: Universal — SI base unit used worldwide
Uses of the Ampere today
- Electrical circuit design and fuse/breaker ratings
- Battery and charger current specifications
- Motor and appliance current draw ratings
History of the Ampere
The ampere is named after André-Marie Ampère (1775–1836), a French physicist and mathematician regarded as one of the founders of classical electromagnetism, for his early work relating electric current to magnetic force.
Originally defined via the force between two parallel current-carrying wires, the ampere was redefined on 20 May 2019 by fixing the elementary charge at exactly 1.602176634 × 10⁻¹⁹ coulombs, so it can now be realized without reference to a specific physical apparatus.
Historical origin. Ampere was not the invention of a single named person; it developed through the process described above.
Understanding the Milliampere (mA)
Milliampere is 0.001 ampere units.
Ampere — sources
- BIPM SI Brochure, 9th edition — Official definition of the ampere since the 2019 redefinition.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many milliamperes are in 1 ampere?
1 ampere equals 1,000 milliamperes, using the exact defined conversion factor rather than an estimate.
How do I convert ampere to milliampere?
Multiply the ampere value by 1000. The converter above does this instantly to whatever precision you set.
How do I convert milliampere back to ampere?
Use the reverse factor: 1 milliampere equals 0.001 amperes. You can also use the swap control in the converter above to flip the direction instantly.
What is a ampere?
Ampere (A) measures electric current. The SI base unit of electric current. It is classified as a SI base unit.
What is a milliampere?
Milliampere (mA) is a unit of electricity.
Is the ampere to milliampere conversion exact?
Yes. Both ampere and milliampere are defined by fixed standards rather than physical artifacts, so the factor of 1000 used above is exact to as many digits as you choose to display.
Where is the ampere still used today?
Universal — SI base unit used worldwide
What's the difference between voltage, current, and resistance?
Voltage (volts) is the electrical potential difference driving current through a circuit. Current (amperes) is the rate of flow of electric charge. Resistance (ohms) is how much a component opposes that flow. They're related by Ohm's law (V = I × R), but they are distinct physical quantities, and this page converts between units of just one of them.