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Electric Current Converter
Convert between amperes, milliamperes and kiloamperes.
It takes as little as 30 milliamperes crossing the chest to send a human heart into fibrillation, and as much as 30,000 amperes — a million times more — to strike the ground in a typical bolt of lightning. Current spans that entire range in ordinary daily life, which is exactly why it gets measured in three different prefixes.
Current unit conversions
| Unit | Symbol | In amperes |
|---|---|---|
| Milliampere | mA | 0.001 A |
| Ampere | A | 1 A |
| Kiloampere | kA | 1,000 A |
Why household wiring uses whole amps and biology uses milliamps
A household circuit breaker is typically rated 15 or 20 amps, and a phone charger draws well under 1 amp — both comfortably described in whole or fractional amperes. The human nervous system, by contrast, responds to currents thousands of times smaller, which is why medical and safety standards work in milliamperes instead.
Kiloamperes only show up at the extreme end: lightning strikes, short-circuit fault currents in high-voltage substations, and large industrial arc-welding or smelting equipment. You will never see a kA figure on a household appliance.
What different currents do to a person
| Current | Typical effect |
|---|---|
| 1 mA | Threshold of perception, a faint tingle |
| 5–10 mA | Painful shock, muscle contraction |
| 10–20 mA | Loss of muscle control, cannot let go of the source |
| 30–50 mA | Breathing difficulty possible with prolonged contact |
| 100–200 mA | High risk of fatal ventricular fibrillation |
| 2 A+ | Cardiac arrest and severe internal burns likely |
Why current, not voltage, is what actually kills
- Voltage is the push; current is what actually flows through the body and disrupts the heart’s electrical rhythm.
- Dry skin has high resistance and limits current from a given voltage; wet skin has far lower resistance, which is why bathrooms carry stricter electrical codes.
- A ground-fault circuit interrupter (GFCI) is set to trip at around 4–6 mA of leakage, well below the danger threshold, specifically because of this biology.
- The same voltage can be harmless or lethal purely depending on the path current takes and how much resistance stands in its way.
Electric current questions
How do I convert amps to milliamps?
Multiply by 1,000. A current of 0.25 A is 250 mA. Going the other way, divide the milliamp figure by 1,000 to get amps.
What is the difference between current and voltage?
Voltage is the electrical pressure pushing charge through a circuit; current is the actual rate of charge flow, measured in amperes. A battery can sit at 9 V with almost no current flowing until a circuit is completed and something starts drawing power.
Why do circuit breakers get rated in amps rather than watts?
Because a breaker protects the wire itself from overheating, and wire heating is determined by current, not power. The same breaker rating protects correctly regardless of the voltage of the circuit it sits on.
How much current does a lightning bolt actually carry?
A typical cloud-to-ground strike carries around 30,000 amps (30 kA), though it can range from a few kiloamps to well over 100 kA for the most intense strikes. The strike lasts only a fraction of a second, but the peak current is enormous.
Is a higher amperage rating on a charger dangerous for my phone?
No, a charger only supplies the current a device actually requests through its charging circuitry; a higher-rated charger will not force extra current into a device that does not ask for it. Modern USB chargers negotiate current with the device before charging begins.
