When it comes to SMS marketing, every character counts. Whether you're sending a limited-time offer, a booking reminder, or a product update, knowing how SMS character limits work can save you money, prevent message breaks, and improve the overall impact of your campaigns.
From understanding the technical constraints of SMS text length to applying smart marketing tactics, this guide will walk you through everything you need to know to craft efficient and effective text messages without getting cut off or overcharged.
SMS character limit: The basics
A single SMS is limited to 160 characters but only under specific conditions. This limit is based on the GSM-7 encoding standard, which supports basic Latin characters, numbers, and common punctuation.
To capture a customer’s attention you have about 2-3 seconds. People have endless streams of content available at their fingertips, which makes competing for their attention more difficult than ever before, especially as marketers. If that weren’t enough, a study solidified this claim by discovering that the average human’s attention spanis less than that of a goldfish—at a mere 8 seconds.The first 160 characters—no matter what medium you use—will ultimately determine the overall success of your campaign.
While keeping your messages to 160 characters can be challenging, keep in mind that this restriction doesn’t mean you have to compromise your marketing goals. SMS messages usually take 2 seconds to read, which is why it has a much higher impact on a customer’s decision. This doesn’t necessarily mean that your campaign objective needs to be completed upon the first send. Instead, by designing campaigns to leave clients wanting more, you can build-up anticipation before accomplishing your objectives.
That said, you can also strategically build messages to prompt immediate action. While 160 characters may not seem like much, the possibilities are actually limitless.
If your message uses non-standard characters, such as emojis, curly quotes, or non-Latin scripts like Chinese or Arabic, your message will automatically switch to Unicode (UTF-16) encoding. When this happens, your SMS character length drops to just 70 characters per message.
GSM-7 vs Unicode: What you need to know
GSM-7 encoding = 160 characters per message
Unicode encoding (UTF-16) = 70 characters per message.
Just one Unicode character triggers the switch, even if the rest of the message uses standard characters.
These technical rules are invisible to most users, but they directly impact your costs and delivery experience especially when you're sending messages at scale.
What happens when you exceed the SMS character limit?
If your message goes beyond the 160-character limit (or 70 characters with Unicode), it doesn’t just get cut off. Instead, your SMS provider uses a method called concatenation to join multiple segments into one message.
Each segment contains a small piece of invisible data, called the User Data Header (UDH), that tells the recipient's phone how to piece the message back together. This metadata takes up 7 characters per segment, slightly reducing the usable length of each message part.
Concatenated SMS breakdown:
Standard GSM-7 messages after the first segment = 153 characters per segment.
Unicode messages after the first segment = 67 characters per segment.
Example: A 300-character message using GSM-7 would be split into 2 full segments (153 + 147 characters) and billed as 2 SMS.
This has two key implications:
Your message may cost more, depending on how many segments are required.
Your message performance may drop, especially if the customer doesn’t scroll to read the full content.
That’s why we strongly recommend keeping your message within the 160-character sweet spot whenever possible.
Best practices for managing SMS character length
Sending a great SMS isn’t just about sticking to a number, it’s about getting your point across quickly, clearly, and persuasively. Here are our top tips for making every character count:
1. Keep messages under 160 characters
The 160-character limit isn’t just a technical constraint—it’s a best-practice standard. These messages:
Load faster.
Are cheaper to send.
Deliver better engagement.
Get read in 2–3 seconds.
2. Avoid special characters and emojis
They may seem small, but one emoji can change everything. It triggers Unicode encoding, reducing your available characters to 70 per message and increasing your chance of sending multi-part messages. When in doubt, stick to standard characters.
3. Use shortened links
Don’t waste 30+ characters pasting a full URL. Kudosity’s platform includes a built-in URL shortener that creates compact, trackable links—saving space and boosting engagement.
4. Lead with the most important info
Your audience may only read the first few lines of your message, especially if it gets split into segments. Make sure your CTA, offer, or key information is upfront.
5. Watch out for personalisation variables
Adding names or other dynamic fields boosts engagement but be mindful that long names can push messages beyond the 160-character limit. Kudosity’s platform helps you preview messages with personalisation included, so there are no surprises.
Why SMS character length impacts cost and performance
The number of characters in your SMS affects more than just formatting. It influences:
Campaign cost: More characters = more segments = higher spend.
Delivery speed: Longer messages can delay delivery on some networks.
Read rates: Shorter messages are more likely to be read quickly and completely.
Spam compliance: Overly long or cluttered messages are more likely to be flagged.
By staying within a single-segment SMS (160 characters for GSM or 70 for Unicode), you're maximising your budget, user experience, and impact.
Check your text length before you send
Want to know exactly how long your SMS message is and whether it will be split into multiple segments?
Use our SMS Character Counter to:
Instantly see your current character count.
Detect if your message includes Unicode.
Preview how many segments your message will require.
Ensure your campaign stays on-budget and on-message.
Whether you're crafting a one-off message or running a national campaign, this tool gives you full visibility and control over your SMS content.
Final thoughts: Why every character matters
When it comes to SMS marketing, brevity is power. The SMS character limit might seem small, but it’s a feature—not a bug. It forces clarity, creativity, and customer-focused thinking.
By understanding the technical and strategic side of SMS character length, you can craft messages that are faster to read, cheaper to send, and more likely to convert.
With Kudosity’s smart tools including a character counter, URL shortener, and real-time preview you have everything you need to build better messages, stay compliant, and drive results.
Ready to take control of your SMS marketing? Explore our messaging platform or try the SMS Character Counter today.
FAQs
Do you have to stick with 160 characters?
No, but longer SMS campaigns are generally less effective.
You can send SMS marketing campaigns that are up to 612 characters long through a process of concatenation, but we recommend that you stay within 160. Remember, you only have 2-3 seconds to invoke an action from your customer, so make it as succinct as possible.
What should I have in my 160 character message?
It depends because there are so many different use cases. But here are some guidelines:
Personalise your messages by using their name to make them feel special.
Make sure you identify yourself so that customers know who you are.
Ensure that your offer and call-to-action is clear and concise.
Have options for the customer to interact with—use links, give them the ability to respond etc.
These are only a handful of ideas to keep in mind, but if you’re looking for more details, you can also read our five best practice tips to create an SMS campaign.
What are 160 Character examples and tips
Now that you are aware of how you can structure a message, here are a couple of examples and tips to keep in mind to improve your SMS effectiveness.
Example One
This example is a simple “Welcome” SMS that adheres to the 160 character rule. It’s vital to know when to change the message based on how you communicate with your clientele. Keep that in mind that an SMS reminder or notification is different than an alert.
Also, be aware of the “Opt-out reply STOP” line. It’s required to remain spam compliant for sales and marketing messages, and it’s part of your character count.
Example Two
This example shows the use of line breaks and a clickable link. Line-breaks are characters. Reducing them can save you a couple of extra characters.
For higher engagement, adding a link is always a good option. However, be aware NOT to paste an entire URL in the message since it will severely impact your character limit. Instead, use our built-in URL shortener.
