Understanding the difference between SMS and MMS

You will learn

Learn how SMS and MMS messages are similar and different as well as when and where to use them.

SMS marketing is the generic term most people use for marketing using text messages. SMS and MMS have distinct capabilities:

• SMS (short message service)
• MMS (multimedia messaging service)

Similar: consent

MMS and SMS are alike in an important way: consent.

MMS marketing falls under SMS. If someone consents for SMS, it also counts as consent for MMS. If you already have someone’s permission for SMS marketing, you can start sending them MMS messages immediately.

Difference: images and GIFs

What truly makes MMS different from SMS is the ability to include media in the message:

• SMS can only send text, symbols, and emojis
• MMS can do the same as SMS as well as include images and GIFs

Adding media to an SMS message transforms it into an MMS message. Examples of media in Klaviyo are listed below:

• Images, including dynamic images
• GIFs
• Virtual contact cards

You will see the image, GIF, or contact card appear in the preview.

Difference: country availability

SMS with Klaviyo is currently available in several countries, including the US, Canada, UK, Ireland, Australia, etc.

MMS is more limited. It is only available with these sending number types:

• United States toll-free numbers and short codes
• Canadian toll-free numbers
• Australian long codes

MMS is not available with Canadian short codes and Australian branded sender IDs.

Difference: cost

Under Klaviyo's Mobile Messaging plan, message costs vary by message type and country. Sending 1 MMS costs more than sending 1 SMS segment to the same country.

To see the mobile messaging rates specific to your plan, go to Settings > Billing > Account usage, then click View text message ratios. Compare the SMS and MMS rates for the countries you send to.

Billable messages include:

• Campaigns
• Flows
• Conversations

Preview messages and automatic subscription confirmations, unsubscribe confirmations, and help replies are not charged.

When picking a plan, remember to take into account how many MMS messages you plan to send.

Difference: character limit

Another thing separating MMS and SMS is the character count.

• A single SMS segment can have up to 160 characters
  • 70 with an emoji or special characters
• MMS messages can have 1,600 characters

Longer SMS messages are split into multiple segments, and each segment is charged separately. Check the estimated message count before sending, especially when you use emojis, special characters, or dynamic content.

What counts toward character count?

Everything you put in the message counts toward character count, except for any media. This includes:

• Text
• Links
• Special characters
• Emojis
• Variables

How long should SMS and MMS messages be?

A best practice for all text messages is to keep the content short and to the point.

Message type	General recommendation	Reason
SMS	155 characters without emojis or special characters	Leave a few extra characters below the 160-character single-SMS limit. With emojis or special characters, stay below the 70-character limit instead. The final count can vary when you use shortened links or dynamic content.
MMS	200 characters	MMS allows for much longer messages, but typically, you should still try to keep the text short and to the point

Why isn't the estimated character count in Klaviyo exact?

If you are using shortened links or dynamic content, the exact character count will vary depending on the recipient.

For instance, if you use the variable to insert someone’s first name (i.e., {{ person|lookup:"first_name"|default:'there' }}), a preview using the name Jordan counts 6 characters for the name. A message sent to Alexandra counts 9 characters for the name.

When to use SMS vs. MMS

Use MMS sparingly. In general, MMS performs worse or equal to an SMS but costs more.

However, test what works for your brand. In some cases, sending an image or GIF can enhance the message, such as to make it more personal by showing more of your brand. MMS can also be useful for sending out information about a new product, giving you a stage to showcase it visually.

Do not include media for the sole purpose of writing a longer message: most customers do not want to read longer messages or see irrelevant visuals. In these cases, it is better to use an SMS and shorten the content to make it fit into one message.

SMS messages are also better when you want to convey information as quickly as possible. This can be the case if you’re having a flash sale or even for the first message in your welcome series.

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