Why does SMS have a 160-character limit?

A single SMS using the standard GSM-7 alphabet fits 160 characters. Go over and the message is split into concatenated segments of 153 characters each, with a small header reserving the rest. Each segment is billed separately, so one tidy 160-character message is cheaper and arrives as a single notification.

Why does adding an emoji cut my limit to 70?

Emoji and most non-Latin characters force the message into UCS-2 (unicode) encoding, which only fits 70 characters per single SMS and 67 per concatenated segment. One emoji can quietly double your send cost. The tool detects this and switches the limit automatically.

Is the STOP opt-out actually required?

For marketing SMS, yes in most jurisdictions. US TCPA rules and UK PECR/GDPR both require a clear, free way to opt out, and 'Reply STOP' is the standard. Carriers also enforce STOP handling. Removing it risks fines and getting your sender number blocked.

Do I need consent before sending marketing texts?

Yes. SMS marketing requires prior express consent from the recipient — they must have opted in. Buying lists or texting customers who only gave you a number for orders is a violation. Keep dated records of every opt-in.

Should I include my brand name in the message?

Always lead with it. Recipients see an unknown short code or number, so naming your brand up front prevents the message reading as spam and improves trust and click-through. It is also required for sender identification in several markets.

SMS Marketing Campaign Builder

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SMS that fits one message and stays legal

SMS marketing has the highest open rate of any channel, but it is unforgiving: you have one screen of text, a hard character budget, and a legal obligation to let people opt out. This builder assembles a compliant marketing text from its required parts — brand name, offer, a call to action with a short link, and the STOP opt-out — while counting characters live so you do not silently overflow into multiple billed segments.

How it works

The tool composes your message in the order recipients expect and then measures it against the real SMS encoding rules:

Brand:  identifies the sender up front
Offer:  the reason to act
CTA:    a verb + short link (Shop: brand.co/sale)
STOP:   the required opt-out line

It detects whether your text stays within GSM-7 (the 7-bit alphabet used for plain Latin text) or forces UCS-2 unicode encoding. GSM-7 fits 160 characters in a single SMS; any emoji or special character drops the limit to 70. When you exceed the single-message limit, messages are concatenated in segments of 153 characters (67 for unicode), and the tool shows exactly how many billed segments your draft will use.

Tips and example

Lead with your brand so the text never reads as spam, then make the offer concrete and the CTA a single verb plus a short link. Avoid emoji unless they earn their place — one can halve your character budget and double your cost. Keep the whole message under 160 GSM-7 characters so it sends as a single SMS and lands as one notification. Never send to a number that did not explicitly opt in, and always keep the STOP line: it is both the law and the difference between a campaign and a carrier ban.