Choosing the output unit before converting a measurement

Use the unit the recipient or form expects, then label it immediately. Confirm that the source and target measure the same kind of quantity—length to length, mass to mass, not volume to mass without extra information.

Decide appropriate precision for the task. A recipe, engineering drawing, and room estimate need different rounding. Keep the original value alongside the conversion when mistakes would be costly.

What is the destination and required unit?