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. Technically, though, there are 2 different formats that have distinct capabilities:
- SMS (short messaging services)
- MMS (multimedia messaging services).
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
Messages always start as SMS messages, but adding media instantly 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.
On the other hand, MMS is more limited. MMS is only available for:
- All United States numbers
- 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 an MMS message costs more than sending an SMS message.
To see the mobile messaging rates specific to your plan, go to Settings > Billing > Account Usage > View Text Message Ratios.
Rates apply to all messages sent using Klaviyo, including:
- Campaigns
- Flows
- Conversations
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.
- SMS messages can have up to 160 characters
- 70 with an emoji or special characters
- MMS messages can have 1600 characters
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 | Leave a few extra characters so that you don't run up to the 160 character limit, as the estimated count in Klaviyo is not always accurate |
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're using the variable to insert someone's first name (i.e., {{ person|lookup:"first_name"|default:'there' }}), the estimated character count is 6. However, if someone's name is Alexandra, the actual count will be 9 characters.
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.
Additional resources
- Understanding MMS image and GIF best practices
Learn best practices for sending images and GIFs in text messages so that they display nicely to recipients.
- Getting started with SMS
- SMS marketing strategies for all levels [+12 Pro tips]