You can find your account number in the T-Mobile app and on My T-Mobile.
If you have a Pay in Advance (Prepaid) account, your mobile number is your account number.
From your mobile device with the T-Mobile app
Open the app. If you don't have it, download it now.
- Tap Menu > BILLING & PAYMENTS.
- Tap View Bill Summary. You'll see your account number under Bill summary.
From your computer
- Log in to My T-Mobile.
- Select BILLING. You'll see your account number under Bill summary.