Fundamentals BroadNet answer

What is the SMS character limit?

Last reviewed July 22, 20261 min readReviewed by BroadNet engineering

Quick answer

A single SMS holds 160 characters in the GSM-7 alphabet, or 70 characters if the message contains any Unicode (UCS-2) character such as an emoji or a non-Latin script. Longer messages are split into concatenated segments of 153 GSM-7 characters (or 67 Unicode characters) each, because a header is reserved to reassemble them — and every segment is billed separately.

Plain-language definitionVendor-neutralReviewed July 22, 2026

The long answer

Everything worth knowing, nothing that isn't.

§01

Why 160 — and why 70

The 160-character limit comes from SMS's 140-byte payload encoded with the 7-bit GSM alphabet. The moment one character falls outside GSM-7 — an emoji, curly quotes, or Arabic, Chinese, or Cyrillic text — the whole message switches to 16-bit UCS-2 encoding, which fits only 70 characters. See /answers/what-is-encoding-gsm-7-ucs-2.

§02

How concatenation changes the count

Past the single-segment limit, each part must carry a User Data Header so the handset can stitch them back together, which drops the usable length to 153 (GSM-7) or 67 (Unicode) characters per segment. So a 161-character GSM-7 message is billed as two segments, not one. See /answers/what-is-concatenated-sms and /answers/what-is-udh-sms.

§03

Keep messages to one segment

Because you pay per segment, a single stray Unicode character can double a bulk campaign's cost. Strip emoji, use straight quotes, shorten links, and validate the count before sending with the /tools/sms-segment-calculator. See /answers/how-to-reduce-sms-costs.

BNWritten by the BroadNet engineering team·Operating carrier-grade messaging since 2003, headquartered in Dubai·Editorial standards

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