# How To Calculate Milliamps

Ohm's Law is the basic formula for electronics. With it, we may calculate Resistance (Ohms), Voltage (Volts) or Current (Amps) by knowing any two of the three values.

## How to Calculate Milliamps

### Step 1

A milliamp is one one-thousandth of an amp. By calculating the value in amps and dividing by one thousand, you will have a value of current in milliamps.

### Step 2

Ohm's Law is Voltage = Resistance X Current. The derivations are: Resistance = Voltage / Current Current = Voltage / Resistance

### Step 3

Calculate Current using your known Voltage and Resistance as shown in Step 2. Current (I) = Voltage (V) divided by Resistance (R) I = V/R Ex: if your voltage is 12V and resistance is 200 Ohms I = V/R = 12 / 200 = 0.06 Amps

### Step 4

Knowing your Current in Amps, multiply by 1000 to see the value in milliamps Ex: 0.06 Amps x 1000 = 60 milliamps

### Step 5

Given a known Voltage and Current, you may also derive Power (Watts). Power = Voltage times Current ( P = V x I ) Ex: 12V x 0.06A = 0.72W or 720 milliwatts

### Things Needed

- Known voltage value
- Known resistance value

### Cite This Article

#### MLA

Donahue, Christopher. "How To Calculate Milliamps" *sciencing.com*, https://www.sciencing.com/calculate-milliamps-5152625/. 24 April 2017.

#### APA

Donahue, Christopher. (2017, April 24). How To Calculate Milliamps. *sciencing.com*. Retrieved from https://www.sciencing.com/calculate-milliamps-5152625/

#### Chicago

Donahue, Christopher. How To Calculate Milliamps last modified March 24, 2022. https://www.sciencing.com/calculate-milliamps-5152625/