SMS link length: how one URL costs you a second segment

An SMS is billed by the segment, not the message, and the boundaries are not where people think. 160 characters is the limit for a single message. Cross it and every segment drops to 153, because concatenation adds a header that eats into the payload. Put one emoji anywhere in the text and the whole message re-encodes to UCS-2, where the numbers become 70 and 67.

That is the whole cost model, and a URL is usually the single largest item in it.

The arithmetic

Encoding	Single message	Per segment when split	Triggered by
GSM-7	160	153	Latin letters, digits, common punctuation
GSM-7 with extensions	160, but some characters cost 2	153	Square brackets, curly braces, backslash, tilde, caret, vertical bar, euro sign
UCS-2	70	67	Any emoji, curly quotes, most non-Latin scripts

The extension set deserves a line of its own. Those nine characters are encoded as an escape plus the character, so each one costs two of your 160. A curly apostrophe pasted from a word processor is worse still — it is not in GSM-7 at all, so it drags the entire message into UCS-2 and cuts your budget by more than half.

Where the URL fits

Link	Characters	Left for words
https://example.com/summer-sale-2026?utm_source=sms&utm_medium=sms&utm_campaign=summer	86	74
https://example.com/summer-sale-2026	36	124
https://gc.mw/abcde	19	141
gc.mw/abcde	11	149
gc.mw/sale	10	150

The tagged URL in the first row is not an exaggeration; it is what a marketing platform produces by default. It takes over half the message before you have written a word, and it pushes almost any real sentence into a second segment — which doubles the bill for the entire send, not for the overflow.

The last two rows are the same campaign with the same tracking. The parameters moved onto the link, where they are applied during the redirect and can be edited afterwards, instead of being spelled out in every copy of the message.

Writing the message around the link

Put the link last. People scan the first few words to decide whether to read, and a URL at the start reads as spam to both humans and filters.

Say who you are in the first three words. Rana Motors: costs 12 characters and prevents the reply that says "who is this".

Drop the pleasantries. Hi there! We hope you're doing well. is 36 characters — a quarter of the message — that nobody has ever been glad to receive in an SMS.

Use one link. Two links in a 160-character message is a message with no room for a reason to click either.

1. 1

   Write the message with a placeholder for the link

   Get the words right at 140 characters or fewer, before the URL exists.

2. 2

   Create one short link per campaign, and per segment if you have segments

   Separate links beat one link with different UTM values, because the click counts stay separate at the source.

3. 3

   Attach UTM parameters to the link, not the message

   On Pro, in the UTM parameters section of the link editor. The message stays short; the destination still sees utm_medium=sms.

4. 4

   Send one to yourself first

   On the real route, to a real handset. This catches the two failures that matter: a message that split, and a link the handset did not turn blue.

What the short link gives back

SMS is the channel with the least native measurement. There is no open rate, no pixel, and no referrer — clicks from a text message arrive with an empty referrer and land in the direct bucket in your website analytics.

The redirect is the only reliable event in the whole flow. It gives you the click count, the unique visitor count, the country and the device, timestamped, before the destination has loaded. For a channel you are paying for by the segment, that is the number the invoice should be measured against.