SMS (Short Message Service) character limits depend on the encoding used. GSM 7-bit encoding (alphanumeric and basic symbols) allows 160 characters per message, while Unicode (UCS-2) encoding (for Japanese, emoji, etc.) allows only 70 characters.

Messages exceeding the limit are automatically split into multiple SMS segments. When split, header information is added, reducing the effective character count to 153 (GSM) or 67 (Unicode) per segment. SMS marketing practical guides teach effective SMS writing.

For business SMS, split messages incur per-segment charges, making it cost-effective to keep messages within a single segment.

Japanese SMS uses Unicode encoding, so the 70-character limit applies. When including URLs, using URL shorteners helps conserve character space. Business messaging optimization guides cover messaging strategies including SMS.