Current Converter
Convert between electric current units — ampere, kiloampere, milliampere, biot, abampere, statampere, and the CGS electromagnetic and electrostatic current units.
Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.
Result
1 A = 1000 mA
1 Ampere = 1000 Milliamperes
1 Milliampere = 0.001 Amperes
1 A in every supported unit
What is a Current Converter?
Electric current is one of the seven base physical quantities in the International System of Units (SI) — alongside length, mass, time, luminous intensity, temperature, and amount of substance. It measures the rate at which electric charge flows past a point in a circuit, and its SI unit is the ampere (A), defined since 2019 by fixing the exact numerical value of the elementary charge. Alongside the modern SI ampere, this converter also covers the historical CGS-EMU units (biot, abampere, EMU of current, CGS e.m. unit — all four names for the same 10-ampere quantity) and the CGS-ESU units (statampere, ESU of current, CGS e.s. unit — three names for the same tiny 3.336×10⁻¹⁰-ampere quantity), which appear throughout older physics literature written in Gaussian units.
This converter is used whenever someone needs to translate a current value across scales or unit systems — reading a fuse, circuit breaker, or battery capacity rating, sizing wiring for an electrical installation, comparing a lightning strike's peak current (often quoted in kiloamperes) against everyday electronics currents (usually in milliamperes), or converting a historical physics text's CGS-Gaussian current figure into a modern SI ampere value. Every unit below is defined relative to the ampere, so any two current units — modern or historical — can be converted directly and consistently.
Conversion chart: Ampere to Milliamperes
Conversion table
| Ampere (A) | Milliampere (mA) |
|---|---|
| 0.01 A | 10 mA |
| 0.1 A | 100 mA |
| 1 A | 1000 mA |
| 2 A | 2000 mA |
| 3 A | 3000 mA |
| 5 A | 5000 mA |
| 10 A | 10000 mA |
| 20 A | 20000 mA |
| 50 A | 50000 mA |
| 100 A | 100000 mA |
| 1000 A | 1000000 mA |
Supported Units
| Unit | Symbol | In Ampere |
|---|---|---|
| Ampere | A | 1 A |
| Kiloampere | kA | 1000 A |
| Milliampere | mA | 0.001 A |
| Biot | Bi | 10 A |
| Abampere | abA | 10 A |
| EMU of Current | EMU | 10 A |
| Statampere | stA | 3.33564E-10 A |
| ESU of Current | ESU | 3.33564E-10 A |
| CGS e.m. unit | CGS e.m. | 10 A |
| CGS e.s. unit | CGS e.s. | 3.33564E-10 A |
About These Parameters
- Value
- The current value you want to convert, expressed in the "From" unit. Accepts decimals, and can represent anything from a microcontroller's milliampere-level draw to a lightning strike's kiloampere-scale peak current.
- From Unit
- The unit your input value is currently measured in — a modern device spec's ampere or milliampere rating, or a historical figure quoted in biots, abamperes, or another CGS-Gaussian current unit.
- To Unit
- The unit you want the result converted into. Use the swap button to flip From and To instantly, which is handy when translating an older CGS-based figure into the modern SI ampere or vice versa.
How Current Conversion Works
The Formula
Every unit here is defined by a fixed multiplier relative to the ampere. To convert a value from one unit to another:
result = value × (factor of "From" unit ÷ factor of "To" unit)
For Ampere → Milliampere: multiply by 1000. For example, 1 A × 1000 = 1000 mA.
From CGS to SI
Before the SI system unified electromagnetic measurement, 19th-century physicists worked with two parallel centimeter-gram-second (CGS) unit families: the electromagnetic system (CGS-EMU), whose current unit was the abampere (also called the biot or "EMU of current"), and the electrostatic system (CGS-ESU), whose current unit was the statampere (also called "ESU of current"). The two families differ enormously in scale — one abampere equals 10 amperes, while one statampere equals only about 3.336×10⁻¹⁰ amperes — because they were built from Coulomb's law and Ampère's force law using different fundamental scaling assumptions, with the ratio between the two systems tracing back to the speed of light. The modern ampere, formally adopted in 1948 and redefined in 2019 via the elementary charge, replaced both CGS conventions with a single coherent, exactly reproducible standard.
Why So Many Names for the Same Value?
Biot, abampere, "EMU of current," and "CGS e.m. unit" are four different historical names that all refer to the exact same 10-ampere quantity, just coined in different contexts — Biot honors the physicist Jean-Baptiste Biot, "abampere" reflects the CGS-EMU "ab-" naming convention shared with abvolt and abohm, and "EMU of current" / "CGS e.m. unit" are the generic labels used in international unit tables to flag the electromagnetic-system current unit explicitly. The same pattern repeats on the electrostatic side with statampere, "ESU of current," and "CGS e.s. unit." Keeping all these historical names in one converter makes it possible to convert any older scientific paper's current figure — however it happens to be labeled — into a modern SI ampere value.
Example
A current of 1 A equals 1000 mA. For scale, a typical USB port supplies around 0.5-3 amperes, a household circuit breaker might trip at 15-20 amperes, and a direct lightning strike can carry a peak current well over 30,000 amperes (30 kiloamperes) for a fraction of a second.
Frequently Asked Questions
What is the difference between ampere and milliampere?
A milliampere is one-thousandth of an ampere (1 mA = 0.001 A). The ampere is the SI base unit used for everyday-scale currents like appliance draw or wiring capacity, while the milliampere is the practical unit for the much smaller currents typical of electronic circuits, sensors, and battery capacity ratings.
Are biot, abampere, and EMU of current really the same unit?
Yes — all three (plus "CGS e.m. unit") are different historical names for the identical CGS-electromagnetic current unit, equal to exactly 10 amperes. They arose from different naming conventions used in 19th- and early 20th-century physics literature rather than representing physically distinct quantities.
Why is the statampere such a tiny fraction of an ampere?
The statampere comes from the CGS electrostatic unit system, built directly from Coulomb's law without the ampere's scaling conventions. The huge size gap between it and the ampere — roughly a factor of 3×10⁹ — traces back to the speed of light, which relates the electrostatic and electromagnetic CGS unit families to each other.
How is the ampere defined today?
Since the 2019 redefinition of the SI, the ampere is defined by fixing the elementary charge at exactly 1.602176634×10⁻¹⁹ coulombs. One ampere is the current corresponding to a flow of exactly 1/(1.602176634×10⁻¹⁹) elementary charges per second — about 6.24×10¹⁸ charges per second — replacing the older force-between-parallel-wires definition used from 1948 to 2019.