How many characters does an SMS actually allow?

In this article: ► How SMS length is counted ► A practical solution when content runs too long

SMS has been on the market for many years and businesses still depend heavily on it as the most direct and immediate way to communicate with customers, because no other form of communication matches its immediacy. Given how important it is, do you know what the character limit is? And what happens if an SMS runs too long? It turns out English and Chinese characters are counted differently — and does your SMS provider give you enough technical support to work out the count?

The character limit If your SMS contains only Latin letters or Arabic numerals, the content has no double-byte characters and each SMS can carry more of them. If your SMS contains at least one non-Latin character — a Chinese or Japanese character, for instance — the content is double-byte and each SMS can carry far fewer.

With no Chinese characters, up to 160 characters counts as one message; beyond that it counts as two or more. With Chinese or Japanese characters present, up to 70 counts as one message; beyond that it counts as two or more.

Once an SMS exceeds the limit it is split into multiple segments, and depending on the handset model all the parts are reassembled into one complete message (displayed in a single bubble).

The whole operation sounds complicated, which is why we designed the chart below so you can see the character calculation for each SMS at a glance:

So beyond sending your messages, every provider should give businesses an SMS character calculator, so merchants can correctly estimate the character count and how many segments a message will split into before sending — and get the best cost-effectiveness out of it.

A practical solution when an SMS runs too long If the information you need to send is detailed and the content is long, then with SMS’s character limit you may well need three or more messages per send, multiplying your costs and blowing the budget. This is where MMS, which has no character limit, becomes the best answer.

Recently, with the pandemic still severe, one of our brand clients had to contact all their customers by message to notify them of the brand’s latest commercial arrangements. The notice was fairly detailed, and had the brand insisted on SMS each send would have required as many as eight messages. We immediately suggested switching to MMS. Beyond removing the length limit, the message also carried multimedia files, which made it far easier for the brand’s customers to retain the new arrangements.