SMS is a funny thing. Even though most of us are perfectly familiar with it in everyday life, the rules and technical limits suddenly become very clear once you start using the channel at scale. As private consumers we often have subscriptions with unlimited texts, but the price per message becomes much more relevant when you’re sending to many recipients.
This guide will help you count the number of characters in a message, and decode how many characters you actually have available.
One Message = 160 Characters
The simplest answer is that one SMS gives you 160 characters to play with. That includes spaces, line breaks, full stops and so on. But this only applies if you’re using “standard” characters. In SMS terms, that means letters from the English alphabet and a handful of other Western characters.
Danish characters are fortunately included (so æ, ø and å each count as one character), while Icelandic characters such as ú are treated as special characters.
Multiple Messages = 153 Characters Each
If you write longer messages, they are stitched together for the recipient. So yes, you can send a message of, say, 200 characters. But you’ll pay for two SMS per recipient.
Here’s the catch: it takes 7 characters per SMS to code them together. So if you go over 160 characters, the maths works out like this: 153 + 153 characters for two SMS, 153 + 153 + 153 for three SMS, and so on.
Special Characters = 70 Characters
Things get really interesting when you include “non-standard” characters, such as Icelandic ones. These messages need to be encoded before they can be sent. In practice, this means the message has to be “packed” in a special way so the GSM network can deliver it. It will still display correctly for the recipient, but you’ll lose character space: you only have 70 characters.
For longer texts, 3 characters are used for stitching, so the count becomes 67 + 67, and so on.
When you compose SMS messages in, for example, Communications, the counter will reflect the number of characters you actually have available. Even inserting a single Icelandic character will make the counter drop to 70 instead of the usual 160.
Watch Out for Merge Fields
If you use merge fields in your SMS – for example inserting the recipient’s first name – this will also affect the final character count. Clearly there’s a difference between “Ib” and “Sidsel-Kirstine” when it comes to length.
And if you’re writing the message in Danish or English but merge in names that contain special characters, the entire message will need to be encoded – which again reduces the character limit.