Open the Phone app
Dial *#06# and note the IMEI number
Go to Samsung’s warranty or support check page
Enter the IMEI or serial number
Check the warranty start date or activation date shown
Open Settings
Tap About phone
Tap Status information
Check the device purchase or activation details if available
Sign in to your Samsung account
Open Registered devices
Check the registration date
Contact Samsung Support
Provide the IMEI or serial number
Ask for the activation date
Check the original purchase receipt
Compare the purchase date with the activation date