Why some text messages are blue and some green?

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If you own an iPhone, you may have noticed something odd in the Messages app: Some messages are blue and some are green. What's the deal with that?

Short answer: Blue ones have been sent or received using Apple's iMessage technology, while green ones are "traditional" text messages exchanged via Short Messaging Service, or SMS.

Does this matter? In the grand texting scheme of things, should you care whether your messages are blue or green?

The color question

Maybe yes, maybe no. Let's start by making sure you have all the necessary information. A standard SMS text message is delivered over the same voice networks used for phone calls. Back in the bad old days, carriers charged by the message (often 10 to 25 cents per!). Then they bundled a fixed number of messages into your calling plan, and now most of them offer unlimited messaging.

In the interim, Apple unveiled iMessage, which looks and acts like standard SMS but actually relies on data networks (cellular or Wi-Fi, whatever you're connected to). That affords two benefits: freedom from carrier rates for SMS (if you're paying extra for it or have a capped plan) and a wider set of messaging features.

Indeed, iMessage allows you to do things standard SMS can't, like share your location, send walkie-talkie-style voice messages, check message delivery and even see if someone's in the process of writing you back (indicated by those three little dots that appear below your last message).

With the arrival of iOS 10, Apple added even more iMessage goodies, like apps, stickers and bubble effects.

Blue FTW

Ah, but here's the rub: You can only use iMessage with other iDevice owners. If you have an iPhone and you use the Messages app to contact an Android, BlackBerry or Windows Phone user, iOS recognizes there's no iMessage at the other end and switches (downshifts?) into SMS mode. Your indication that has happened? Green word bubbles instead of blue.

However, you may end up seeing green even if you're corresponding with another iPhone. There are three possible causes:

• iMessage isn't activated on your device. (Tap Settings, Messages, then check to see if the feature is switched on. If it is, you should also activate "Send as SMS." Note that you may need to perform a one-time sign-in using your Apple ID.)
• iMessage isn't activated on the recipient's device.
• There's no data network available. If your phone can still connect to a voice tower, it will default back to SMS.

So, is there any reason you should disable iMessage and rely exclusively on SMS? Only if data is at a premium: Although text messages are very small, picture and video messages can consume a fair bit of data -- and if your service plan offers unlimited texting but limited data, you may prefer to switch off iMessage in favor of SMS.

On the flip side, if you're corresponding with fellow iPhone users but still seeing only green messages, ask them to enable iMessage at their end so you can enjoy the various benefits of the service. Many users have no idea iMessage is even a thing, and don't realize it's not enabled.

Editors' note: This article was originally published on Feb. 24, 2015, and has since been updated.

• If your iPhone messages are green, it means that they're being sent as SMS text messages rather than as iMessages, which appear in blue.
• iMessages only work between Apple users. You'll always see green when writing to Android users, or when you're not connected to the internet.
• If all of your iPhone messages are green, you should make sure iMessage is turned on in Settings.
• Visit Insider's Tech Reference library for more stories.

You may have noticed that the text messages in your iPhone's Messages app can appear as either green or blue. 

The difference? Green messages are ordinary SMS text messages, while blue messages are using Apple's proprietary iMessage format. 

Here's everything you need to know about why your iPhone is sending green messages, and how to fix it if you think it's a mistake.

The difference between SMS and iMessage, explained

Ordinary SMS text messages are sent using your cellular voice service, and don't use the internet or your data plan. All mobile phones — Android, iPhone, and otherwise — use SMS in some way. 

However, iPhones also use iMessage, which was built to send messages over the internet, specifically between Apple devices. 

When sending messages to another Apple device, your iPhone will use iMessages. But if you're texting an Android phone, or you're not connected to the internet, your iPhone will use SMS. You can't send an iMessage to an Android phone.

But while iMessages are limited to other Apple devices, they have a number of advantages over SMS. 

• iMessages don't count against your texting plan — instead, they use Wi-Fi or your data plan, depending upon whatever's available when you send or receive the message. 
• The Messages app shows when someone is writing an iMessage to you (those familiar pulsing dots).
• iMessages can also contain information that SMS does not, such as your location. 
• You can choose to be told when an iMessage has been delivered and read.

How to enable iMessage on your iPhone if it's turned off

The bottom line is that iMessage is generally better than SMS, and your iPhone will use it whenever possible — you don't have to do anything special to send an iMessage to another Apple device, aside from having iMessage turned on. 

Here's how to make sure iMessage is turned on:

1. Start the Settings app.

2. Tap "Messages."

3. Make sure iMessage is turned on by swiping the button to the right.

Related coverage from Tech Reference:

• How to turn off read receipts on your iPhone so that senders don't know when you've read their iMessage

• How to stop robocalls and other spam calls from reaching your iPhone

• How to text a GIF on your iPhone using the built-in GIF keyboard in Messages or a third-party app

• How to save an entire text conversation on your iPhone

• How to save audio messages on your iPhone and change your settings so audio messages stop deleting after 2 minutes

Dave Johnson

Freelance Writer

Dave Johnson is a technology journalist who writes about consumer tech and how the industry is transforming the speculative world of science fiction into modern-day real life. Dave grew up in New Jersey before entering the Air Force to operate satellites, teach space operations, and do space launch planning. He then spent eight years as a content lead on the Windows team at Microsoft. As a photographer, Dave has photographed wolves in their natural environment; he's also a scuba instructor and co-host of several podcasts. Dave is the author of more than two dozen books and has contributed to many sites and publications including CNET, Forbes, PC World, How To Geek, and Insider.

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