Short answer
Voltage is a potential difference between two points, measured in volts. Current is the rate of charge flow, measured in amperes. A battery can have voltage across its terminals even when an open circuit has no sustained current. 1 2
Voltage describes potential difference; current describes charge flow. A circuit’s resistance and arrangement affect how they relate.
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At a glance
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| Question | Voltage | Electric current |
|---|---|---|
| Measures | Energy difference per unit charge | Charge flow per unit time |
| Unit | Volt (V) | Ampere (A) |
| Open circuit | May be present | No sustained closed-path flow |
The table summarizes the cited definitions and the article’s stated scope. 1 2
What each thing is
Voltage. Electric potential difference: a difference in electric potential energy per unit charge between two points. 1
Electric current. The rate at which electric charge flows past a point or through a cross-section. 2
Key differences
In a simple resistive circuit, voltage and current are linked by resistance, but they are not the same quantity. Their values must be measured in different ways and can vary independently when circuit conditions change. 1 2
How to tell them apart
Read the units: V labels voltage, A labels current. A voltmeter is connected across two points; an ammeter measures flow in a circuit branch. Electrical measurement on live systems requires appropriate equipment and training. 1 2
Where they overlap
Both describe electrical behavior of the same circuit. Electrical power depends on both, which is one reason everyday discussion sometimes blurs them. 1 2
Edge cases
Alternating current circuits can have time-varying voltage and current that are not in phase. A high voltage does not by itself specify the current through a body or component; resistance, path and duration matter. 1 2
Why the distinction exists
The terms separate the driving potential difference from the actual movement of charge, allowing circuits to be analyzed and designed. 1 2
Common misconceptions
Voltage is not “how much electricity is flowing.” Current is not a synonym for electrical energy. 1 2
Examples
A disconnected 9-volt battery has a terminal voltage but no sustained current through an external load. Connect a suitable circuit and charge flows. 1 2
Sources
Sources checked October 3, 2026.
- OpenStax — Electric Potential Energy: Potential Difference. Potential difference.
- OpenStax — Current. Electric current.