Know the real message size before you send.

Why a character counter is not enough

SMS billing is driven by encoded message parts, not only by the number of characters you can see. Standard GSM-7 text usually fits up to 160 septets in one part. A non-GSM character can switch the message to UCS-2, where the usual single-part capacity is 70 UTF-16 code units. Multipart headers reduce the capacity available in every part.

Characters from the GSM extension table, including braces, square brackets, the euro sign and the caret, use two septets. Emoji and some scripts can use more than one UTF-16 code unit. That is why the calculator reports both visible characters and encoding units.

Turn the calculator into a pre-send safeguard

The free tool is useful for manual checks. The API applies the same calculation automatically to final messages, templates and campaigns before a delivery request is created.

const response = await fetch(
  "https://textpreflight.kadircoteli.workers.dev/api/v1/sms/analyze",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "Authorization": "Bearer TPF-YOUR-LICENSE-KEY"
    },
    body: JSON.stringify({ text, recipients, unitPrice, currency: "USD" })
  }
);