How to Convert mA to Amps (Milliamps to Amps)
Quick Answer: To convert milliamps (mA) to amps (A), divide by 1,000. Example: 20 mA ÷ 1,000 = 0.020 A.
This guide will show you exactly how to convert mA to Amps. This is also known as converting from milliamps to amps. It is a very easy calculation to do once you see how it works. This is a key skill for any electronics project.
mA ↔ Amps Converter
What are Milliamps and Amps?
First, it is important to know that milliamps (mA) and amps (A) both measure the same thing: electrical current. Think of them like inches and feet. They are just on a different scale.
The key fact to remember is that there are 1000 milliamps in 1 amp. Most small electronics, like LEDs, use current that is best measured in milliamps. However, many formulas use amps. This is why you need to know how to convert between them.
How to Convert mA to Amps: The Formula
To convert from milliamps (mA) to amps (A), you just need to divide by 1000. This is the same as moving the decimal point three places to the left.
Let's use an example. If you have a value of 20mA, here is how you convert it:
- Method 1: Divide by 1000. So, 20.0mA / 1000 = 0.020A.
- Method 2: Move the decimal point 3 places to the left. So, 20.0mA becomes .020A.
How to Convert Amps to mA
To convert from amps (A) back to milliamps (mA), you do the opposite. You need to multiply by 1000. This is the same as moving the decimal point three places to the right.
For example, if you have 0.020A and want to convert it back to mA:
- Method 1: Multiply by 1000. So, 0.020A * 1000 = 20.0mA.
- Method 2: Move the decimal point 3 places to the right. So, 0.020A becomes 20.0mA.
Quick Conversion Chart: mA to Amps
Here is a simple chart for quick reference:
| Milliamps (mA) | Amps (A) | Common Use |
|---|---|---|
| 1 mA | 0.001 A | Microcontroller sleep current |
| 2 mA | 0.002 A | Low-power indicator LED |
| 10 mA | 0.010 A | Reduced brightness LED |
| 20 mA | 0.020 A | Standard LED (most common) |
| 25 mA | 0.025 A | High-brightness DIP LED |
| 30 mA | 0.030 A | Some SMD LEDs |
| 50 mA | 0.050 A | High-output SMD |
| 100 mA | 0.100 A | Small motor, sensor |
| 350 mA | 0.350 A | 1W high-power LED |
| 500 mA | 0.500 A | USB 2.0 max per port |
| 700 mA | 0.700 A | 3W high-power LED |
| 1000 mA | 1.000 A | 10W high-power LED |
| 1500 mA | 1.500 A | USB 3.0 max per port |
| 2000 mA | 2.000 A | Large LED array |
| 3000 mA | 3.000 A | COB LED module |
Using the Conversion in Ohm’s Law (Worked Example)
Here is a real-world example of why you need this conversion. Say you have a 12V power supply and a red LED rated at 20 mA with a 2V forward voltage. To calculate the resistor you need:
- Convert mA to A: 20 mA ÷ 1,000 = 0.020 A
- Calculate voltage drop across resistor: 12V − 2V = 10V
- Apply Ohm’s Law (R = V / I): 10V ÷ 0.020A = 500 Ω
- Choose nearest standard value: 510 Ω (next value up in the E24 series)
Need to find the exact resistor for your LED circuit? Use our free LED Resistor Calculator — it does the math automatically and shows you which resistor to buy.
Why This Conversion is Important for LEDs
This conversion is very useful when you work with electronics and LEDs. Current is a key value you will see when you set up a circuit for your LEDs. Datasheets for LEDs often list their forward current in milliamps (mA). However, when you use formulas to calculate which resistor you need, it is often easier to work in amps (A). Therefore, knowing **how to convert mA to amps** is a vital skill. Using the right current limiting resistors will make sure you keep the current levels safe for your LEDs.