🔄 Electric Current

Electric Current Converter

From microamps in a sensor to kiloamps in a substation — convert every scale of electrical current. Enter your value and press Convert.

Written and reviewed by SM Arijul Islam · Last reviewed 28 October 2026 · Editorial standards · Report an error

About the electric current converter

The ampere is one of the seven SI base units and measures the rate of electric charge flow — one coulomb per second. Most modern electronics run in milliamps, while household circuits and industrial equipment are rated in amperes and kiloamps.

Factors and formulas

1 A = 1,000 mA = 1,000,000 µA
1 kA = 1,000 A · 1 MA = 1,000,000 A
1 abampere (biot) = 10 A
1 statampere ≈ 3.335641 × 10⁻¹⁰ A
Ohm's law: current (A) = voltage (V) ÷ resistance (Ω)

Working out a circuit? Use Ohm's law with the Voltage Converter, Resistance Converter and Power Converter.

How to convert electric current

Electric current is the rate at which charge flows, measured in amperes (A). One ampere is one coulomb of charge passing a point each second. Metric prefixes do most of the work in practice: a milliampere (mA) is one thousandth of an ampere, a microampere (µA) one millionth, and a kiloampere (kA) one thousand amperes. Current is always measured through a circuit, not across it, which is the key difference from voltage.

Common electric current conversions

One ampere expressed in other units of electric current
Unit	1 ampere equals
Nanoampere (nA)	1,000,000,000
Microampere (µA)	1,000,000
Milliampere (mA)	1,000
Kiloampere (kA)	0.001

Everyday uses

Sizing fuses, breakers and cable
Reading component and device datasheets
Budgeting battery drain
LED, motor and relay currents
USB and low-voltage power delivery

Frequently asked questions

How many milliamperes are in an ampere?

1,000, so 0.5 A is 500 mA and 2,500 mA is 2.5 A.

What does a 2 A USB port mean?

It can supply up to 2 amperes, which at 5 volts is about 10 watts of power.

Is current the same as power?

No. Power in watts equals current in amperes multiplied by voltage in volts.

What happens if a device draws more current than the supply?

The voltage usually sags, a fuse blows or the supply shuts down, so ratings should always be matched.

More worked examples

2,000 mA is 2 A, because there are 1,000 milliamperes in an ampere.
A charger rated 2 A at 5 V delivers 10 W, since power is voltage times current.
A 10 A circuit at 230 V can supply up to 2,300 W.
Half an ampere is 500 mA, which is also 500,000 microamperes.

Typical appliance currents at 230 V

Approximate current drawn by common appliances on a 230 volt supply
Appliance	Current
LED bulb, 10 W	about 0.04 A
Phone charger, 10 W	about 0.04 A
Laptop charger, 65 W	about 0.28 A
Microwave, 900 W	about 3.9 A
Electric kettle, 2,000 W	about 8.7 A
Electric heater, 2,000 W	about 8.7 A

Common mistakes to avoid

Confusing current with power. Amperes alone say nothing about how much energy is being used until you know the voltage.
Dividing by 100 instead of 1,000 when going from milliamps to amps.
Assuming a device always draws its rated current. Motors and compressors surge well above their running current at start-up.
Adding up currents from appliances on different voltages. The totals are only meaningful per circuit and per voltage.

Further questions

What is an ampere?

The SI unit of electric current: one coulomb of charge passing a point each second.

How do I convert amps to watts?

Multiply the current by the voltage, so W = A × V. For alternating current you also need the power factor.

What is the difference between an amp and an amp-hour?

An amp measures the rate of flow. An amp-hour measures quantity of charge, so one amp-hour is one amp flowing for one hour, or 3,600 coulombs.

How much current is dangerous?

Surprisingly little. Around 30 mA through the body can paralyse breathing and about 100 mA can trigger ventricular fibrillation, which is why household circuits at 10 to 16 A are treated with respect.

Sources and standards

The ampere is defined by taking the fixed numerical value of the elementary charge. NIST SP 811 reproduces that definition and the customary current units, and the page keeps current, charge and current density as separate quantities.

1 amp to milliamps, watts to amps and ohms law

One amp is 1,000 milliamps, so 1 amp to milliamps is a straight multiply by 1,000. To convert watts to amps you need the voltage: I = P ÷ V, so a 2,300 W appliance on 230 V draws 10 A, while the same appliance on 120 V draws 19.2 A.

Ohms law calculator

V = I × R, I = V ÷ R and R = V ÷ I. A 12 V supply across a 470 Ω resistor carries 25.5 mA. For a parallel resistor calculator, use 1/R = 1/R₁ + 1/R₂ + …; two 100 Ω resistors in parallel give 50 Ω, and two unequal ones always give less than the smaller value.

Four-band resistor colour code
Colour	Digit	Multiplier	Tolerance
Black	0	× 1	—
Brown	1	× 10	± 1%
Red	2	× 100	± 2%
Orange	3	× 1k	—
Yellow	4	× 10k	—
Green	5	× 100k	± 0.5%
Blue	6	× 1M	± 0.25%
Violet	7	× 10M	± 0.1%
Grey	8	—	± 0.05%
Gold	—	× 0.1	± 5%

How do I read a 4 band resistor? The first two bands are the significant digits, the third is the multiplier and the fourth is the tolerance. Brown-black-red-gold is 1, 0, × 100, ± 5% — 1,000 Ω or 1 kΩ.

LED resistor calculator and voltage drop

For an LED, R = (supply voltage − LED forward voltage) ÷ desired current. A red LED with a 2 V drop on a 5 V supply at 20 mA needs (5 − 2) ÷ 0.02 = 150 Ω. A voltage drop calculator for cable uses the loop length, the current and the conductor resistance: on 2.5 mm² copper at 20 A over 30 m, the drop is roughly 4.2 V, which is why long runs need thicker cable.