Why Does My SMS Turn into an MMS Automatically

Have you ever tried sending a simple text (SMS) and noticed it automatically changed into an MMS? This is a common occurrence and is not a bug—it happens due to certain messaging behaviors or settings.

Here’s an informative breakdown of why SMS messages can convert into MMS and how you can manage this feature effectively on your OPPO device.

What’s the Difference Between SMS and MMS

• SMS (Short Message Service) is a standard text message, limited to 160 characters, with no media content.

• MMS (Multimedia Messaging Service) allows for longer texts, images, subject lines, and group messaging but may incur additional charges.

Reasons Why SMS Automatically Converts to MMS

1. One or More Recipients is an Email Address: If you send a message to an email instead of a phone number, your device treats it as an MMS.

2. The Message is Too Long: SMS has a 160-character limit. If your message exceeds this, your device may convert it to MMS, especially if emojis or special formatting are involved.

3. The Message Includes a Subject Line: Adding a subject turns a plain SMS into an MMS. You can remove the subject to avoid this conversion.

4. Attachments or Pictures Are Included: Any message containing images, videos, audio, or other media will be sent as an MMS.

5. Group Messaging Settings: When sending messages to multiple recipients, your phone may default to MMS depending on how your group messaging is configured.

How to Prevent Group Messages from Becoming MMS (GMS Devices)

If you’re using a GMS (Google Mobile Services) OPPO phone, here’s how to keep group messages as individual SMS texts:

1. Go to [Messages] app > Tap your profile icon (top right)

2. [Messages settings] > [Advanced]

3. Tap [Group messaging] > Select: “Send an SMS reply to all recipients and get individual replies (mass text)”

This ensures each recipient gets a separate SMS, and replies won’t turn the thread into a group MMS.

Related articles:

How to Customize Message Reply With SMS

What is the SMS Character Limit on OPPO Phone?

OPPO Phone Sends or Receives Duplicate SMS Repeatedly

* Pictures, settings, and paths might differ from those of your phone, but these won't affect the description in this article.