What is an easy way to tell if my handheld anemometer is accurate?

Question

What is an easy way to tell if my handheld anemometer is accurate?

Answer 1

With another one known to be accurate or if you were to drive at a set speed in a car that you believed the speedometer in and held it directly into the relative wind on a calm day.

Answer 2

Measure its accuracy by doing tests. If its windy outside and the reading is something like 30 mph, then that's probably good accuracy. Also measure the precision by seeing if multiple measurements are close to each other.