Text Message RCS: What It Is and How It Differs From SMS
By Free SMS Gateway teamUpdated 8 min read
An RCS text message is a chat sent through Rich Communication Services, a messaging standard that upgrades ordinary texting with typing indicators, read receipts, high-resolution photos and videos, and group chats. If RCS is not available for a conversation, your phone sends a plain SMS instead.
People who search "text message RCS" usually mean ordinary texting that has been quietly upgraded. Below: what RCS is, how it differs from SMS and MMS, why a chat sometimes drops back to SMS, and which SMS character limits still apply.
What Is RCS (Rich Communication Services)?
RCS is a messaging standard, not an app. It lets your phone's built-in messaging app send richer chats than SMS, with nothing extra to download or sign up for.
What the RCS acronym stands for
RCS stands for Rich Communication Services. "Rich" covers what plain text lacks: typing indicators, read receipts, high-resolution media and group chats.
SMS stands for Short Message Service. That is the full form of SMS, and the SMS meaning sits in the name: short, plain-text messages. New to the older format? The SMS basics guides cover it.
How RCS differs from a standard SMS text message
A standard SMS is a short, plain-text message sent over the mobile network's messaging channel. An RCS chat travels over an internet connection, mobile data or Wi-Fi, and adds the features above. Both use the recipient's phone number and appear in the same messaging app, so the two can look alike at first glance.
How Is RCS Different From SMS and MMS?
RCS differs from SMS and MMS in what a conversation can carry and show: SMS is short plain text, MMS adds media attachments, and RCS adds high-resolution media, status icons and group chats.
| Feature | SMS | MMS | RCS |
|---|---|---|---|
| Text length | 160 GSM-7 or 70 Unicode characters per message | Text with attached media | Not bound by the 160-character SMS limit |
| Photos and video | Not supported | Supported | High-resolution photos and videos |
| Sent, delivered, read icons | Not shown | Not shown | Available |
Message length and media support
SMS is capped at 160 GSM-7 or 70 Unicode characters per message, and longer texts are split into parts (covered below). RCS is not bound by the same 160-character limit. For media, MMS lets you attach pictures and video to a text, while RCS lets you send high-resolution photos and videos (Google Messages Help).
Read receipts, typing indicators and group chats
RCS chats can show typing indicators and read receipts, and they support group chats. SMS and MMS do not show sent, delivered or read icons (Google Messages Help), so on those channels you get no status in the chat.
Why Does My RCS Message Turn Into a Green SMS?
A green bubble does not mean your message was downgraded: on an iPhone, blue is iMessage only, and both RCS and SMS/MMS messages appear in green (Apple Support). A message turns into plain SMS only when RCS cannot be used for that conversation.
The better clue is the status icons. A message that never shows sent, delivered or read icons probably went out as SMS or MMS.
Common fallback triggers: network, device, or carrier support
These are the general reasons a chat falls back:
Network: RCS needs mobile data or Wi-Fi. Without a usable connection, your phone may send an SMS instead.
Device: The other person's phone or messaging app does not support RCS, or they have chat features turned off.
Carrier: The carrier on either side does not support RCS for that conversation.
Support varies by phone and carrier and changes over time, so we do not publish a list here. Check your messaging app's settings or ask your carrier. After a fallback, SMS rules apply, including the length limits below.
Which SMS Character Limits Still Apply When RCS Falls Back?
When a chat falls back to SMS, the standard SMS limits apply: 160 characters in a single GSM-7 message or 70 in Unicode, and 153 or 67 per part once a longer text is split. RCS is not bound by those limits. The SMS character limit guide has the full rules.
GSM-7 vs Unicode character limits
One SMS carries a 140-byte payload (3GPP TS 23.040). The alphabet decides how many characters fit (3GPP TS 23.038): GSM-7 fits 160, while Unicode (UCS-2) uses two bytes per character and fits 70.
| Encoding | Single SMS | Each part of a multipart SMS |
|---|---|---|
| GSM-7 | 160 characters | 153 characters |
| Unicode (UCS-2) | 70 characters | 67 characters |
The switch applies to the whole message. Any Urdu letter, emoji or "smart" punctuation, such as curly quotes, moves the entire text to Unicode. A 100-character message containing one emoji therefore goes out as two parts. That is the Unicode SMS character limit at work.
How multipart (concatenated) SMS messages are split
A text longer than one message is split into parts. Each part carries a header that lets the receiving phone reassemble them, and that header takes space, so each part holds 153 GSM-7 or 67 Unicode characters.
160 GSM-7 characters: 1 message
161 GSM-7 characters: 2 parts (153 + 8)
306 GSM-7 characters: 2 parts; character 307 starts a third
Message-part counts follow fixed rules, and many providers bill per part, so check yours. The SMS character counter tool shows the SMS character count and number of parts for your text.
Sources: 3GPP TS 23.038, 3GPP TS 23.040, Apple Support, Google Messages Help.
Where to Get RCS or SMS Sending Tools for Your Business
Businesses can get RCS or SMS sending tools from a mobile carrier's business messaging service or from messaging API platforms. Compare at least two before you choose.
Your mobile carrier's business messaging service. Ask your operator what it offers for business texting and whether RCS is included.
Twilio, Vonage and Sinch. These platforms offer RCS and SMS through developer APIs.
Whichever you pick, check how it counts message parts, which countries and carriers it covers, and what happens when an RCS message falls back to SMS. For background on sending texts online, see online SMS explained.
WaSMS is another option to compare. WaSMS is run by the same team as this site.
Check how many characters and message parts your text will use before you send it: open the SMS character counter tool.
What does RCS stand for in a text message?
RCS stands for Rich Communication Services. It is a messaging standard that lets your phone's built-in messaging app send chats with typing indicators, read receipts, high-resolution photos and videos, and group chats. When RCS is not available, the same app sends an ordinary SMS (Short Message Service) instead.
Is RCS the same thing as a regular SMS text message?
No. SMS is the original text format: plain text, limited to 160 GSM-7 or 70 Unicode characters per message. RCS is a newer standard that is not bound by the 160-character SMS limit and adds features such as read receipts and typing indicators. Both appear in the same messaging app, so they can look alike.
Why did my chat switch from RCS to SMS, and why is the bubble green?
A chat switches to SMS when RCS cannot be used for that conversation, for example when there is no data connection, the other person's phone or carrier does not support RCS, or chat features are off. A green bubble alone does not prove a switch: on an iPhone, blue is iMessage only, and both RCS and SMS/MMS are green (Apple). Sent, delivered and read icons do not show on SMS or MMS (Google), so missing icons are a better clue.
Does RCS use the same character limit as SMS?
No. RCS is not bound by the 160-character SMS limit, but SMS still is whenever a chat falls back. One SMS holds 160 GSM-7 or 70 Unicode characters, and each part of a longer message holds 153 or 67. The FreeSMSGateway SMS character counter tool shows your character count and message parts before you send.
Do both people need RCS for it to work?
Yes. An RCS chat needs RCS support at both ends, covering both people's phones, messaging apps and carriers, plus a data connection. If either side cannot use it, the message is sent as SMS or MMS instead.
Frequently asked questions
What does RCS stand for in a text message?
RCS stands for Rich Communication Services. It is a messaging standard that lets your phone's built-in messaging app send chats with typing indicators, read receipts, high-resolution photos and videos, and group chats. When RCS is not available, the same app sends an ordinary SMS (Short Message Service) instead.
Is RCS the same thing as a regular SMS text message?
No. SMS is the original text format: plain text, limited to 160 GSM-7 or 70 Unicode characters per message. RCS is a newer standard that is not bound by the 160-character SMS limit and adds features such as read receipts and typing indicators. Both appear in the same messaging app, so they can look alike.
Why did my chat switch from RCS to SMS, and why is the bubble green?
A chat switches to SMS when RCS cannot be used for that conversation, for example when there is no data connection, the other person's phone or carrier does not support RCS, or chat features are off. A green bubble alone does not prove a switch: on an iPhone, blue is iMessage only, and both RCS and SMS/MMS are green (Apple). Sent, delivered and read icons do not show on SMS or MMS (Google), so missing icons are a better clue.
Does RCS use the same character limit as SMS?
No. RCS is not bound by the 160-character SMS limit, but SMS still is whenever a chat falls back. One SMS holds 160 GSM-7 or 70 Unicode characters, and each part of a longer message holds 153 or 67. The FreeSMSGateway SMS character counter tool shows your character count and message parts before you send.
Do both people need RCS for it to work?
Yes. An RCS chat needs RCS support at both ends, covering both people's phones, messaging apps and carriers, plus a data connection. If either side cannot use it, the message is sent as SMS or MMS instead.