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Ampere vs. Milliampere: What's the Difference?

Edited by Harlon Moss || By Janet White || Updated on October 7, 2023
An ampere (A) is a unit of electric current, and a milliampere (mA) is one thousandth of an ampere, representing smaller currents.

Key Differences

Ampere and milliampere are units of electrical current in the International System of Units (SI). An ampere, symbolized as ‘A,’ is the base unit of electric current and represents the flow of one coulomb of charge per second. A milliampere, on the other hand, is a submultiple unit of electric current, denoted as ‘mA,’ and is one-thousandth of an ampere, making it suitable for measuring smaller currents, typically in more delicate circuits or components.
The conceptualization of ampere and milliampere is crucial for understanding electrical phenomena and is foundational in electrical engineering and physics. Ampere quantifies the rate of flow of electric charge in a conductor and is a determinant in understanding the strength of the electric current in a circuit. A milliampere, by being a fractional unit of an ampere, allows for precise measurements and adjustments in applications where a full ampere would be excessive, such as in medical devices or intricate electronic components.
The application of ampere and milliampere is widespread in the field of electronics and electrical studies. The use of ampere is common in contexts involving larger electric currents, such as household appliances and industrial equipment, as it provides a comprehensive measure of the flow of electricity. In contrast, milliampere is more prevalent in small-scale applications and delicate devices, due to its capability to represent minute currents, thus providing an accurate understanding of the functionality of such devices.
Understanding ampere and milliampere is crucial for anyone involved in the field of electronics, electrical engineering, or physics. While the ampere is foundational and applicable in generalized contexts due to its status as a base unit, the milliampere, with its smaller magnitude, caters to specialized needs, ensuring precision and reliability in sensitive environments and applications.
When it comes to the practical application of these units, an ampere is substantial and is employed in scenarios dealing with substantial electric currents, offering insights into the performance and safety of electrical systems. The milliampere, with its fractional value, is indispensable in scenarios requiring meticulous attention to detail and precision, such as in the calibration of medical and scientific instruments.

Comparison Chart

Unit of Measurement

Base unit of electric current in SI.
Submultiple unit, 1/1000 of an Ampere.




Measures larger currents.
Suitable for measuring smaller currents.


Used in household appliances and industrial equipment.
Common in medical devices and intricate electronic components.


Represents the flow of one coulomb of charge per second.
Represents one-thousandth of the flow of an ampere.

Ampere and Milliampere Definitions


Represents the flow of one coulomb of charge per second.
The circuit is designed to handle a current of up to 15 amperes.


A unit of electric current equal to one-thousandth of an ampere.
The medical device operates at 50 milliamperes.


A unit of electric current in the International System of Units.
The household appliance operates at 10 amperes.


Suitable for representing minute currents in scientific applications.
The scientific instrument measures current in milliamperes for accuracy.


Measures the amount of electric charge passing a point in an electric circuit per unit time.
The electrical device has a current rating of 5 amperes.


Utilized for denoting small electric currents in delicate circuits.
The sensor has a low current consumption of 5 milliamperes.


Utilized to gauge the flow of electricity in a conductor.
Most electric kettles operate between 5 and 10 amperes.


Allows precise measurement of electric current in intricate components.
The LED indicator draws a current of 20 milliamperes.


Indicates the strength of electric current in electrical conductors.
Circuit breakers are triggered when the flow exceeds 20 amperes.


Emphasizes accuracy and precision in measuring small electric currents.
For delicate electronic devices, currents are often measured in milliamperes.


The basic unit of electric current, equal to one coulomb per second and equivalent to the current, flowing in two straight parallel wires of negligible cross section separated by a distance of one meter, that produces a force between the wires of 2.0 × 10-7 newtons per meter of length. The value of an ampere in the International System differs very slightly from that in the meter-kilogram-second-ampere system of units. See Table at measurement.


A unit of current equal to one thousandth (10-3) of an ampere.


A unit of electrical current, the standard base unit in the International System of Units; colloquially amp. Abbreviation: amp, Symbol: A
Definition: The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602
X 10−19 when expressed in the unit C, which is equal to A
S, where the second is defined in terms of ΔνCs. ([https://www.bipm.org/en/si-base-units/ampere The International Bureau of Weights and Measures])


One thousandth (10-3) of an ampere.


The unit of electric current; - defined by the International Electrical Congress in 1893 and by U. S. Statute as, one tenth of the unit of current of the C. G. S. system of electro-magnetic units, or the practical equivalent of the unvarying current which, when passed through a standard solution of nitrate of silver in water, deposits silver at the rate of 0.001118 grams per second. Called also the international ampère.


The thousandth part of one ampère.


A former unit of electric current (slightly smaller than the SI ampere)


One thousandth of an ampere


The basic unit of electric current adopted under the Systeme International d'Unites;
A typical household circuit carries 15 to 50 amps


Is an ampere a base unit in SI?

Yes, an ampere is a base unit of electric current in the International System of Units (SI).

Is ampere used for measuring larger electric currents?

Yes, amperes are used for measuring larger electric currents.

Can a milliampere represent fractional values of an ampere?

Yes, a milliampere represents fractional values, specifically one-thousandth of an ampere.

Are amperes and milliamperes both units of electric current?

Yes, both amperes and milliamperes are units of electric current.

How many amperes are in a milliampere?

A milliampere is one-thousandth of an ampere.

Does an ampere quantify the rate of flow of electric charge?

Yes, an ampere quantifies the rate of flow of one coulomb of charge per second.

Is milliampere suitable for measuring smaller currents?

Yes, a milliampere is suitable for measuring smaller electric currents.

Can amperes measure the flow of electric charge?

Yes, an ampere measures the flow of electric charge in a conductor.

Is milliampere ideal for intricate electronic components?

Yes, milliamperes are ideal for intricate electronic components due to their smaller magnitude.

Can milliampere ensure precision in delicate environments?

Yes, milliamperes ensure precision in measuring electric current in delicate environments.

Is ampere more common in household appliances?

Yes, amperes are commonly used to measure current in household appliances.

Is milliampere more prevalent in medical devices?

Yes, milliamperes are often used in medical devices due to their precision.

Can milliampere measure minute currents in scientific instruments?

Yes, milliamperes are suitable for measuring minute currents in scientific instruments.

Can ampere be used to represent the strength of electric current in conductors?

Yes, amperes are used to indicate the strength of electric current in electrical conductors.

Are milliamperes a submultiple unit of amperes?

Yes, milliamperes are a submultiple unit of amperes, representing one-thousandth of an ampere.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.

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