Here you can try if IMEI number structure is valid by Luhn algorithm. That does not mean that it will tell you that phone is not stolen or lost. It just check the number and check digit and write if it is structured as it should be.
Copy or write in your first 15 digits of IMEI number (without any other characters – write only digits!) and press Validate IMEI
Type your IMEI number (15 digits without other characters, only numbers) and press Validate IMEI
IMEI validity in India
In India you can check you IMEI validity with operator if phone is stolen or lost. All you need to do is to send a message with text IMEI
Example of SMS with text:
IMEI validity in Australia – AMTA
Check the status of your handset for Australian devices