SMS Character Limit 2026: 160 vs 70 Characters Explained

SMS still runs on a 160-character limit set by the 1985 GSM-7 standard — but the moment you add a single emoji or non-Latin character, that limit drops to 70. Here's exactly how SMS character limits work, why your message might silently split into multiple texts, and how to write around it.

The 160-Character SMS Limit: Where It Comes From

SMS was built into the GSM mobile standard in 1985, with a hard 140-byte payload per message. Using the standard GSM-7 character set (which packs each character into 7 bits instead of 8), that works out to exactly 160 characters per segment. This limit has never changed — it's baked into the protocol itself, not a platform decision.

GSM-7 vs Unicode (UCS-2): The Encoding Trap

Here's what trips up most senders: the 160-character limit only applies to the GSM-7 character set — basic Latin letters, numbers, and common punctuation. The moment your message includes a single emoji, a curly quote pasted from Word, or a non-Latin character (Arabic, Chinese, Cyrillic, Hindi), the entire message switches to UCS-2 (Unicode) encoding. Under UCS-2, each character takes 16 bits instead of 7 — and your per-segment limit drops from 160 characters to just 70.

For the complete interactive reference with all fields for every platform, visit our all-platforms character limit cheat sheet — with 16 platforms in one page and links to dedicated tools for each.

Why the Per-Segment Limit Drops When You Go Multi-Part

A single SMS segment gives you the full 160 (or 70) characters. But once your message is long enough to require multiple segments, each segment reserves a few characters (7 bits under GSM-7, 16 bits under UCS-2) for a User Data Header that tells phones how to reassemble and reorder the parts. That's why the multi-segment limit is 153 characters per part under GSM-7, not 160 — and 67 under UCS-2, not 70.

How Many Segments Does Your Message Use?

Most carriers and SMS gateways (Twilio, MessageBird, Vonage) bill per segment, not per message. A 300-character GSM-7 text is two segments — you pay for two messages, and the recipient may see it arrive as two separate texts depending on their phone.

Common Characters That Silently Trigger Unicode

• Curly/smart quotes (" " ' ') pasted from Word or Google Docs instead of straight quotes
• Em dashes (—) and en dashes (–) instead of a plain hyphen
• Any emoji, including seemingly simple ones like 👍 or ❤️
• Accented characters outside the GSM-7 extension table (é, ñ, ü in some contexts)
• Non-Latin scripts: Arabic, Hebrew, Chinese, Japanese, Korean, Hindi, Cyrillic

A message that looks like plain English at 165 characters — under the 160 GSM-7 limit — can silently become a 2-segment UCS-2 message if it contains even one curly apostrophe from a copy-paste. This is the single most common reason SMS costs run higher than expected.

Writing Effective SMS Copy Within 160 Characters

• Type directly into a plain-text field rather than pasting from Word or a rich-text email editor
• If you need an emoji for brand voice, budget for the 70-character Unicode limit rather than assuming 160
• Front-load the offer or action — mobile readers scan the first line, not the whole message
• Use a link shortener; most SMS platforms don't compress URLs the way Twitter/X does

SMS isn't the only channel with strict, non-negotiable character limits. See how Twitter/X counts characters, how Google Ads headlines get truncated, or browse the full social media character limits guide for every platform in one place. If you're running SMS alongside email, our meta description SEO guide covers a similarly strict 155-character constraint. For Amazon sellers running SMS abandoned-cart flows, see our Amazon listing optimization guide, and for LinkedIn outreach sequences that pair with SMS, check our LinkedIn character limits guide.