Messaging • Last Updated 9/29/2023

Mastering SMS character limits: Why it matters

Learn about SMS character limits to avoid these four obstacles businesses face when texting.


By Emily Bowen

SMS and MMS text message

Businesses often face challenges when dealing with SMS character limits. These obstacles can stem from various sources, impacting your messaging campaign's success and bottom line.

To run a successful, cost-effective, user-friendly messaging campaign, you’ll first need to understand character limits, encoding, and message concatenation.

Good news: We’re here to help and will even give you tips on choosing the ideal messaging solution for your campaign.

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In this post, we'll walk you through encoding, concatenation, and messaging options so you can overcome (or avoid) challenges related to SMS character limits.

4 challenges businesses face with SMS character limits

While SMS is a popular and effective communication channel for businesses, navigating the complexities of character limits can present unique challenges. Let’s take a look at the four most common obstacles you might encounter.

1. Inconsistent message formatting and content

When businesses exceed the character limit for an SMS, their messages may be split into multiple parts or even truncated, leading to inconsistent formatting and potentially confusing content. As a result, customers might not receive the complete message or could be left with an incomplete understanding of the communication.

Understanding SMS character limits, encoding types, and message concatenation can help businesses craft concise, well-formatted messages that effectively convey their intended information to recipients.

2. Increased messaging costs

Unintentionally exceeding character limits can lead to higher messaging costs, as messages split into multiple parts are billed separately. By understanding character limits and the impact of encoding on message length, businesses can optimize their messaging strategy to control costs and maximize the value of their SMS campaigns.

3. Limited expressiveness and engagement

SMS character limits can restrict the expressiveness of a business's messages, making it challenging to engage customers with rich content, such as images, videos, or interactive elements. By exploring alternative messaging options like MMS and RCS, businesses can deliver richer, more engaging content, fostering stronger customer relationships and driving better results from their messaging campaigns.

4. Multilingual communication barriers

Character encoding can pose a challenge for businesses communicating with customers in multiple languages. Unicode encoding allows for a diverse range of characters and symbols but also reduces the character limit to 70 per message. By understanding encoding options and their impact on character limits, businesses can develop effective multilingual messaging strategies that cater to their diverse customer base.

Businesses can overcome these challenges by gaining expertise in SMS character limits, encoding, message concatenation, and alternative messaging options like MMS or RCS. Leveraging this expertise can help them optimize their messaging campaigns and enhance customer engagement.

Understanding SMS character limits

Understanding how SMS character limits work plays a vital role in ensuring your messages reach recipients as intended. So let's dive into different encoding types and their effect on character limits.

GSM and Unicode encoding

Two primary types of character encoding exist for SMS: GSM and Unicode. GSM encoding uses a limited character set, allowing up to 160 characters per message. On the other hand, Unicode encoding supports a broader range of characters, including special symbols and characters from various languages. However, it only permits 70 characters per message.

Grasping the differences between these encoding types is crucial for optimizing your SMS campaigns and controlling costs.

Calculating character limits

The character count in a message dictates its parts. For instance, a GSM-encoded SMS with 161 characters would be sent as two separate messages. Likewise, a Unicode-encoded SMS with 71 characters would also require two messages.

Keep character limits in mind when crafting your messages, as exceeding the limit can lead to multiple message parts and increased costs.

At times, sending longer messages that exceed character limits is necessary. In such cases, message concatenation comes into play.

How concatenation works

Concatenation involves breaking a lengthy message into smaller parts and transmitting them as separate SMS messages. The recipient's device then reassembles these parts into a single message. A special User Data Header (UDH) is added to each part to ensure proper reassembly.

Bear in mind that the UDH consumes some of the available characters, reducing the character limit for each part. For example, a concatenated GSM-encoded message can only contain 153 characters per part, while a Unicode-encoded message can have just 67 characters per part.

The impact of concatenation on SMS costs

Concatenated messages can significantly influence your messaging costs. Since each part is billed as a separate message, sending a long message as multiple parts can quickly add up. To manage costs, consider shortening your messages or exploring alternative messaging options.

SMS alternatives: MMS and RCS

When dealing with character limitations, some businesses choose MMS or RCS instead of SMS. In some instances, forgoing SMS may be a wise decision.

When to use MMS

Multimedia Messaging Service (MMS) enables you to send longer text messages, images, audio, and video. MMS is particularly useful when your content exceeds SMS character limits or includes rich media. MMS can also lead to higher customer engagement. However, MMS messages typically cost more than SMS, so weighing the benefits against the costs is important.

Since MMS doesn’t have the 160-character limit of SMS, businesses can share more detailed information or craft more compelling narratives. For instance, a real estate agency could send an MMS message containing a brief property description and a photo, giving potential buyers more context. Likewise, a retail store might use MMS to send promotional images or videos showcasing new products, while a restaurant could send mouth-watering photos of their dishes to entice customers.

Finally, MMS allows businesses to reinforce their branding by including logos, colors, and other visual elements.

While MMS and RCS can both offer advantages over traditional SMS, MMS is the more common choice for a few reasons:

Broader compatibility

MMS is more widely supported across devices and carriers compared to RCS. Both Android and iOS devices support MMS, allowing users to send multimedia messages to a larger audience without worrying about compatibility issues.

Established infrastructure

Since MMS has been around longer than RCS, carriers and messaging providers have already invested in the infrastructure needed to support MMS services. This investment means MMS is more widely available and reliable for users.

Easier integration

MMS can be more straightforward for businesses to integrate into their existing messaging campaigns. Many SMS API providers offer MMS API solutions that enable businesses to send multimedia messages without investing in developing RCS-specific solutions.


MMS is a simple extension of the SMS protocol, allowing users to send multimedia content like images, videos, and audio files without needing to learn a new messaging system. This ease of use can be particularly advantageous for less tech-savvy users or those who prefer a more familiar messaging experience.

When to use RCS

Rich Communication Services (RCS) is an advanced messaging protocol designed to enhance the messaging experience. While RCS offers several advantages over traditional SMS and MMS—such as improved character limits, rich media support, and interactivity—its adoption has been relatively slow for several reasons. However, there are specific situations where using RCS can be beneficial, making it a viable alternative to SMS and MMS:

Enhanced customer engagement

For businesses looking to improve customer engagement, RCS can provide a more interactive and media-rich experience. Features like read receipts, typing indicators, and multimedia sharing can help create a more engaging and personal connection with customers.

Streamlined communication

RCS allows for the exchange of large files, eliminating the need to send multiple messages or rely on third-party apps. This can be particularly useful for businesses that need to send documents, images, or videos as part of their communications.

Group messaging and collaboration

Unlike SMS and MMS, RCS supports group messaging with enhanced features such as participant management, topic customization, and message reactions. This can help improve team collaboration and coordination, especially for businesses and organizations.

Integration with other services

RCS can be integrated with other services and platforms, such as chatbots and AI-powered assistants, to provide a seamless and convenient user experience. This can help businesses deliver more efficient customer support and targeted marketing campaigns.

While RCS does face challenges such as limited device compatibility, carrier support, and competition from messaging apps, it is expected to grow in adoption over time as these issues are addressed. As RCS becomes more widely available and recognized for its benefits, it may emerge as a competitive option in the messaging landscape.

For now, MMS remains a dependable choice for delivering multimedia messages across a diverse range of devices and carriers, and SMS continues to be the popular choice for text-based communications.

Get started with Telnyx for advanced messaging solutions

Telnyx's all-in-one platform with SMS and MMS APIs provides the tools and support you need to implement efficient messaging campaigns and achieve better performance.

With Telnyx, you can overcome challenges associated with SMS character limits and message concatenation, ensuring your messages reach recipients quickly and reliably. Telnyx's adaptive routing feature analyzes message delivery rates and automatically adjusts the route for optimal deliverability. Telnyx also provides analytics and insights tools that offer valuable data on your messaging campaigns. You can leverage these insights to make data-driven decisions that improve your messaging strategy, fine-tune your message content, delivery times, and targeting, maximizing the effectiveness of your SMS campaigns.

Talk to a Telnyx expert today and learn how we can help you elevate your messaging capabilities for enhanced customer engagement, more efficient communication, and a significant boost to your business growth.

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