SMS Character Counter: Count & Check Message Length

An SMS character counter tells you how many characters your text uses and how many messages it will send. One SMS holds 160 standard GSM-7 characters or 70 Unicode characters, and longer texts split into parts of 153 or 67 characters. Paste your text into the free SMS character counter tool to see count, encoding and segments live.

What is SMS and what does the abbreviation mean

SMS stands for Short Message Service. It is the text-message system built into mobile networks: one phone sends a short written message to another without an app. The word "short" is literal, because a single SMS is capped at 140 bytes.

Businesses and developers also send SMS from software through an SMS gateway, a service that connects an app or dashboard to mobile networks.

The first SMS was sent on 3 December 1992. Neil Papworth, a Sema Group engineer, sent the text "Merry Christmas" from a computer to a colleague on the Vodafone network (Vodafone newsroom).

SMS character limits: 160 vs 70 characters

A single SMS holds 160 characters in the GSM-7 alphabet or 70 characters in Unicode, because both fit the same 140-byte message. The alphabet is defined in 3GPP TS 23.038 and the message format in 3GPP TS 23.040.

The two limits are one space measured two ways. GSM-7 uses 7 bits per character (160 × 7 = 1,120 bits = 140 bytes). Unicode (UCS-2) uses 2 bytes per character (70 × 2 = 140 bytes). That is why Unicode roughly halves the limit: each character takes just over twice the space.

GSM-7 (standard) limit: 160 characters

GSM-7 is the default SMS alphabet and gives you 160 characters per message. Plain English letters, digits and everyday punctuation fit, and every character counts, spaces included. Roman Urdu (Urdu written in Latin letters) also stays in GSM-7 if you avoid the triggers below.

Unicode limit: 70 characters

A message switches to Unicode when it contains any character outside GSM-7, and the limit drops to 70. These are the usual triggers:

• Urdu script: any single Urdu letter.

• Emoji: even one.

• Smart punctuation: curly quotes (“ ” ‘ ’) that word processors insert automatically.

The switch applies to the whole message, not just the offending character. A 100-character English message is one segment. Add one emoji and it becomes a Unicode message longer than 70 characters, which needs two. Retype curly quotes as straight quotes before you paste.

Why long messages split into multiple segments

A message longer than one SMS is split into segments, and the receiving phone joins them back together. Each segment travels as its own SMS and carries a small header with a reference number shared by all parts, the total number of parts and the position of this part (3GPP TS 23.040). The phone uses that header to put the parts in order.

Multipart segment size: 153 GSM-7 / 67 Unicode

Each part of a multipart message holds 153 GSM-7 characters or 67 Unicode characters, not 160 or 70, because the header uses part of the 140 bytes. The numbers work out to a 6-byte header, leaving 134 bytes per part. At 2 bytes each, 134 bytes hold 67 Unicode characters. At 7 bits each, they hold 153 GSM-7 characters.

This is the practical character limit for SMS messages once a text runs long. The table shows how your SMS character count maps to segments:

One extra character can add a whole segment: 160 GSM-7 characters is one segment, and 161 is two.

How to count your SMS characters

Count your SMS characters in five steps:

1. Open the free SMS character counter tool.

2. Paste your full message, including links, signature and any opt-out line.

3. Read the character count and the encoding. GSM-7 means a 160-character limit; Unicode means 70.

4. Check the segment count. One segment is one SMS; more than one means parts of 153 or 67 characters.

5. If the encoding shows Unicode and you did not intend that, look for Urdu letters, emoji and curly quotes, replace them, and count again.

Personalized fields change length per recipient. Count the longest realistic value for {first_name} and similar fields, or fill in sample names with the SMS template personaliser. For OTP and notification texts, aim for a single segment. For related how-tos, read more SMS guides on gateways, bulk SMS and templates.

Estimating cost when your message splits

A message that splits into more segments can cost more. Billing depends on your provider, but a common model is one charge per segment, so under that model a two-segment message costs twice a one-segment message. Check how your provider counts segments.

The estimate is segments × recipients × your provider's rate per segment. A 161-character GSM-7 message sent to 1,000 people is 2,000 segments, not 1,000. Dropping an emoji from a 100-character message brings it back from two segments to one. Enter your own rate in the SMS cost estimator to get the total. This page quotes no rates, because they vary by provider and destination.

Where to get a bulk SMS sending service

You can get a bulk SMS sending service from your mobile operator, an API platform or an independent gateway provider.

Start with your own mobile operator's business SMS service, which is one place to look for local sending. Developers often choose an API platform such as Twilio or Vonage to send SMS from code. WaSMS is another option to compare. WaSMS is run by the same team as this site.

Whichever you compare, ask how it counts segments, whether it bills per segment and how it handles Unicode. Then run your own message through the counter first.

Sources

• 3GPP TS 23.038: GSM 7-bit alphabet and UCS-2 character coding.

• 3GPP TS 23.040: SMS message format and the concatenation header.

• Vodafone newsroom: first text message, 3 December 1992.

Count your message now with the free SMS character counter