Watt is the SI unit of power.

In the metric system, milli is the prefix for 10^{–}³.

Therefore, a milliwatt (mW) is equal to one thousandth of a watt.

**Formula to convert W to mW.**

Since we know that a mW is equal to one thousandth of a watt.

Therefore, to convert W to mW, we multiply the watt value by 1,000.

**Power in mW = Power in W x 1,000**

**Example:**

Convert 20 Watts to milliwatts.

**= 20 x 1000**

**= 20,000 milliwatts.**