Here's a free and easy way to tell if your microwave oven is leaking, without buying an expensive microwave oven leakage detector.
1. Place a working cellular phone in your microwave oven and close the door, but do NOT turn the microwave oven on.
2. Now, use any phone to call the cellular phone in the microwave oven.
If the phone rings, it means that your microwave is leaking microwave radiation. If it doesn't, then your microwave oven is fine.
Microwave Oven Radiation Dangers & Safety
Are Microwave Ovens A Source of Danger?