What is the SMS character limit
You’ve probably noticed a text splitting into “1/2” and “2/2” messages, or wondered why a longer message suddenly costs more to send. That’s the SMS character limit at work – most SMS messages cap out at 160 characters, but that number drops to just 70 the moment you use an emoji, a rupee symbol, or a non-English script. Go past the limit and your message gets split into multiple linked parts instead of failing outright, which is what people mean by a “concatenated SMS.”
How does the SMS character limit work
SMS was built on GSM-7 encoding, a 7-bit character set covering the English alphabet, digits, and basic punctuation – and that’s what gives you the classic 160-character limit. The moment your message includes something GSM-7 doesn’t support – emojis, most Indian-language scripts, Chinese characters, even a stray curly quote copied from a Word doc – the whole message switches to UCS-2 (Unicode) encoding, which uses 16 bits per character instead of 7. That cuts your limit down to 70 characters, because the same fixed SMS payload now holds fewer characters. Go over either limit and your message doesn’t just fail – it gets split into a concatenated SMS, multiple linked segments that reassemble on the recipient’s phone. Here’s the catch though: each segment loses a few characters to the header that links the parts together, so GSM-7 segments hold 153 characters each (not 160), and UCS-2 segments hold 67 (not 70). A 200-character English message becomes two segments – and you’re billed for two SMS, not one.
How OneXtel helps with SMS character limits
OneXtel’s platform and its Aura REST API show you the character count and segment count before a message goes out, so you’re never guessing whether that “quick update” is actually being sent as two or three SMS. This matters most with unicode – an emoji dropped into an otherwise plain-English template, or a rupee symbol in an OTP message, can silently push you from GSM-7 to UCS-2 and shrink your limit from 160 to 70 without anyone noticing until the bill looks off. Because OneXtel handles DLT entity, Sender ID, and template registration as part of onboarding, you can check templates against the real character limits before they’re locked in for transactional or promotional sending. And if a message genuinely needs to say more than SMS allows, OneXtel’s multichannel setup lets you fall back to WhatsApp or email instead of chopping it into segments.
Why it matters
Character limits aren’t just a technical footnote – they hit your wallet and your delivery quality. Every extra segment is billed as a separate SMS, so a template that quietly slips into UCS-2 because of one emoji can double or triple your messaging costs at scale, especially on bulk sends to lakhs of recipients. Segments can also arrive out of order or with a delay on some handsets, which looks unprofessional for OTPs and transactional alerts where every second counts. Knowing the limit – and checking your character count before you hit send – keeps your messages predictable, your costs under control, and your delivery clean.