SMS Character Limits and Concatenated Messages Explained

A single SMS can hold 160 characters if it's written using the standard GSM-7 character set (ordinary Latin letters, numbers, and common punctuation). That limit isn't a platform choice - it's baked into the SMS protocol itself and applies everywhere, on every network and every platform.

What happens when a message is longer

A message longer than 160 characters doesn't get rejected - it gets split into multiple linked parts (called a concatenated SMS), each carrying a small header so the recipient's phone reassembles them into one message on screen. Once a message is split, the per-part limit drops slightly, to 153 characters, to leave room for that header. So a message of 300 characters isn't one part with 300 characters - it's two parts, and it's billed as two message credits, not one.

Why emoji and special characters cost more

The 160-character limit assumes standard GSM-7 encoding. The moment a message includes a character outside that set - an emoji, certain accented characters, or characters from non-Latin scripts - the whole message switches to Unicode (UCS-2) encoding, and the per-message limit drops to 70 characters, or 67 per part if it needs to split. A single emoji in an otherwise plain-text message can quietly turn a one-credit send into a two-credit send across an entire campaign.

Practical takeaways

• Keep marketing messages under 160 characters where possible - it's cheaper and reads better
• Avoid emoji and special symbols in bulk sends unless the extra cost is worth it
• Personalisation variables (like a name) count toward the limit once resolved, not as placeholder text
• A long message isn't wrong, but know that it's billed as multiple credits, not one

SimpliSend charges one SMS credit per message sent, and a concatenated message is billed as the number of parts it actually took to deliver - which is standard across the industry, not a platform-specific markup. When drafting a template, it's worth glancing at the character count before sending to a large list; the difference between 158 and 162 characters can be the difference between one credit and two, multiplied by every recipient.