Convert ESU of Current to Statamperes
ESU of Current (ESU) to Statampere (stA) electric current conversion — enter any value below to get an instant result, or use the table for common values.
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 ESU = 1 stA
1 ESU of Current = 1 Statamperes
1 Statampere = 1 ESU of Current
1 ESU in every supported unit
Conversion chart: ESU of Current to Statamperes
Conversion table
| ESU of Current (ESU) | Statampere (stA) |
|---|---|
| 0.01 ESU | 0.01 stA |
| 0.1 ESU | 0.1 stA |
| 1 ESU | 1 stA |
| 2 ESU | 2 stA |
| 3 ESU | 3 stA |
| 5 ESU | 5 stA |
| 10 ESU | 10 stA |
| 20 ESU | 20 stA |
| 50 ESU | 50 stA |
| 100 ESU | 100 stA |
| 1000 ESU | 1000 stA |
ESU of Current (ESU)
Definition: A generic designation for "electrostatic unit of current" within the CGS electrostatic system — numerically identical to the statampere at roughly 3.336×10⁻¹⁰ amperes.
History: The electrostatic-system counterpart to "EMU of current," coined during the same 19th-century effort to systematize CGS units into clearly labeled electromagnetic and electrostatic families before international adoption of the SI.
Current use: Used interchangeably with statampere in older scientific texts; today found almost exclusively in historical references and comparative discussions of the CGS-EMU and CGS-ESU systems.
Statampere (stA)
Definition: The base unit of electric current in the CGS electrostatic (ESU) system, defined as one statcoulomb of charge flowing per second — an extremely small current equal to about 3.336×10⁻¹⁰ amperes.
History: Derived from the electrostatic CGS system's charge unit, the statcoulomb, which was itself defined directly from Coulomb's law without the vacuum permittivity constant that SI units carry. The vast size difference between the statampere and the ampere traces back to the same factor (related to the speed of light) that separates the electrostatic and electromagnetic CGS unit families.
Current use: Essentially obsolete in modern engineering; it appears in historical electrostatics texts and in theoretical physics derivations that favor Gaussian units for elegance in Maxwell's equations.
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 ESU of Current → Statampere: multiply by 1. For example, 1 ESU × 1 = 1 stA.
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 ESU equals 1 stA. 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
How many Statamperes are in 1 ESU of Current?
1 ESU of Current (ESU) equals exactly 1 Statamperes (stA).
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.