Difference between SMS and IM

SMS and IM are messaging services that are used to communicate through mobile devices or computers. Short Message Service (SMS) is used to send small messages from one phone to another. IM messaging services are used to send messages from one computer to another computer through the internet.

Read this article to find out more about SMS and IM and how they are different from each other.

What is SMS?

Short Message Service is a messaging service that is used to send and receive small messages from mobile devices. SMS is one of the popular methods of communication. SMS messages are transmitted via cellular networks, utilising the same call-making equipment as mobile phones.

Initially, text messages are used for personal communications between friends and family members. But now it is used by businesses for different marketing purposes. SMS is therefore a dependable communications service, even though network problems occasionally cause messages to be lost or delayed.

The standard character limit for SMS messages is 160 characters; this restriction dates back to the early days of mobile phone technology, when SMS was originally introduced. Although some messaging programmes have discovered ways to get around this limit by splitting longer messages into numerous SMS messages, this length restriction is still in place today.

Users must have an active mobile phone plan that includes texting in addition to a mobile phone with texting capabilities in order to send an SMS message. Also, they must be aware of the recipient's phone number and the cost of sending SMS messages because some cell plans charge by the message or through a package plan.

What is IM?

Instant messaging (IM) technology is a type of online message service that offers quick, real-time transmission of messages from one sender to another over the Internet. It is quite similar to a live phone conversation; instead of voice-based communication, here we use text-based communication. Two people with the same IM software can share messages or text between them through a private online chat session.

With the use of IM software, users can make a list of contacts or friends and instantly send and receive messages to and from them. Further capabilities offered by these programmes include the ability to share files, make audio and video conversations, and set up channels or groups for debate.

In comparison to email, instant messaging allows for a very instant message exchange. IM is also session-based, with a beginning and an end. Individual messages tend to be brief because IM is designed to replicate face-to-face conversations. On the other hand, email typically adopts a longer-form letter-writing approach.

IM services are commonly available today, and many of them are integrated with social networking platforms. However, each IM service provides a unique proprietary software client, either as a stand-alone application or a browser-based application. There is third-party software that can connect with popular IM services, and some services do offer limited functionality with other IM services.

The following are some of the IM software services that are available −

  • Facebook Messenger

  • Apple iMessage

  • Snapchat

  • WeChat

  • WhatsApp

  • Viber

  • Skype

Difference between SMS and IM

The following table highlights the major differences between SMS and IM −





Short Message Service (SMS) is used to send small messages from one phone to another.

IM messaging services are used to send messages from one computer to another computer through the internet.

Character Limitation

SMS characters are limited to 160.

IM doesn't have any character limitations.

Service Cost

SMS is a paid services

IM is a free services


Its supports the basic emoticons

Its support for a huge range of emoticons


Messages can be accessed without internet and users can respond to messages at any time

Messages can be accessed only through internet and users can’t respond to messages if they are in offline


Not Encrypted



It supports limited multimedia content such as videos, images, and audio files. Due to limitation of size these files need to compress or resize.

It supports huge range of multimedia content such as videos, images, and audio files. Here, there is no limitation of size for files.


Messages are delivered using the cellular networks

Messages are delivered using the internet


In a nutshell, SMS and IM are two different messaging services. The Short Message Service allows mobile devices to send short text messages. On the other hand, instant messaging is used to send large messages from various devices through the internet.

The decision to choose between the two messaging services will eventually depend on the demands and preferences of each person. While SMS is the easier and simple option, IM provides additional features and capabilities.