SMS vs text message and what delivered really means

People use "SMS," "text," "message" and "delivered" as if they mean the same thing. When you start sending texts as a business, they stop being interchangeable. A "text" might be SMS, MMS, iMessage or RCS. A "delivered" status doesn't mean someone read it. And a message you'd call one text can be billed as three.

This post covers the terms newcomers trip over: SMS vs text, what each delivery status tells you, how character counts turn into a bill, and whether every business message runs over SMS.

SMS vs text message: the short answer

SMS (Short Message Service) is the carrier standard for plain-text messages between phone numbers. It works on any phone and needs no app or data connection. It is also the narrowest kind of text: plain characters only, with hard length limits.

"Text message" is the everyday word for anything that shows up in your phone's messaging app. Every SMS is a text message. Not every text message is SMS.

When a platform says it sends SMS, it means the carrier channel specifically, with its rules, its registration requirements and its per-segment billing.

Not every text is SMS

Here's how the main types compare:

The green and blue bubbles on an iPhone show this split. Green is SMS or MMS. Blue is iMessage.

On Ready, the blue line sends business texts as iMessage, with the business's name and photo. It costs $99 a month per line, plus 6 cents per segment sent or received. Texts to Android phones go out from the account's regular number. If the account already had a number they bill at the regular text price; if the blue line came with its green number, they bill at 6 cents a segment once the account registers. The blue line has limits:

• Each line can start up to 50 new conversations a day.
• You can send up to 2 texts to someone before they reply.
• Photos only go out after the person replies.

Details are in the blue line guide.

Character counts and segments: why one text can cost three

SMS is billed in segments, not messages. The limits:

• 160 characters for a single GSM-7 message (standard letters, numbers, basic punctuation)
• 153 characters per segment once a message runs longer, because a little space goes to stitching the parts back together
• 70 characters if the message has any emoji or other non-GSM character (67 per segment when it splits)

A single emoji switches the whole message to the smaller limit, not just the part around the emoji. Ready swaps curly quotes, long dashes and ellipses for plain ones before sending, so text pasted from a word processor won't quietly change your count.

Worked example

Assumptions: 1,000 opted-in contacts on Ready Standard, at $0.0075 per segment plus the $0.0045 carrier fee.

Version A: a 175-character promo with one emoji. That puts it on the unicode limit of 67 per segment. 175 ÷ 67 = 2.6, which rounds up to 3 segments.

• 1,000 × 3 = 3,000 segments
• 3,000 × $0.0075 = $23, plus 3,000 × $0.0045 in carrier fees

Version B: the same offer trimmed to 155 characters with no emoji. That's 1 segment.

• 1,000 segments × $0.0075 = $8, plus 1,000 × $0.0045 in carrier fees

Same campaign, one-third of the segments. Those figures exclude the optional compliance surcharge: scrubbing and landline validation are $0.003 per segment each, and both are off by default.

Replies are billed like sent texts on Ready, so a chatty conversation costs segments in both directions. If you resell texting and your numbers don't match, our segment-count audit post walks through where the gap comes from.

What "delivered" actually means

Most platforms show a status trail along these lines:

• Queued: accepted by the platform and waiting to go out
• Sent: handed to the carrier
• Delivered: the carrier reported that the message reached the handset
• Failed / undelivered: the carrier or platform rejected it, usually with an error code

"Delivered" is a carrier receipt. It means the phone received the message. It doesn't mean the person opened it, read it or saw a notification. SMS has no read receipts. iMessage can show "Read," but only if the recipient has that setting on.

A delivered message can still go unseen. Phones increasingly sort unknown senders into a separate filter or junk folder, and the carrier still reports those messages as delivered. The reliable signal that a message landed is a reply or a click.

The opposite case: when a carrier blocks a message for content or registration problems, you usually see failed or undelivered with an error code. If your campaign is registered and still gets filtered, the cause is usually the wording. Our post on approved campaigns that still get filtered covers that.

Why some texts never deliver

The common causes, roughly in order of frequency:

1. Unregistered traffic. US carriers filter business texts sent from local numbers that aren't registered under A2P 10DLC. On Ready, registration is handled in-app, and most approvals take 2 to 7 days.
2. The number can't receive texts. Landlines and some VoIP numbers won't take SMS. On Ready, numbers already seen as landlines are refused on every account at no charge. Landline validation, which adds a send-time lookup, costs $0.003 per segment and is off by default.
3. The person opted out. Ready refuses opt-outs and numbers on your Ban list before sending and doesn't charge for them.
4. Quiet hours. A campaign or automation text sent during the recipient's quiet hours isn't failed. It waits up to 24 hours for the window and is charged only when it goes out. A one-to-one or API text waits only if the window opens within 6 hours, and is otherwise refused.
5. Content filtering. Shortened links, aggressive wording and certain topics get flagged.

Platforms that build texting into their own product can check a number before sending with the number validation API ($0.003 for each number that gets an answer).

Does all business messaging use SMS?

No. Business texts go out from a few different sender types, each with its own rules:

• 10DLC: a regular 10-digit local number, registered for application-to-person traffic
• Toll-free: 800-style numbers with their own verification process
• Short code: 5 to 6 digit numbers for high volume
• iMessage or RCS: separate channels that aren't SMS at all

There's also a distinction between A2P (application-to-person) and P2P (person-to-person) texting, which changes which rules apply. Our A2P vs P2P explainer covers that, and our sender type comparison helps you choose between 10DLC, toll-free and RCS.

Quick glossary

• Segment: the billing unit for SMS (160, 153, 70 or 67 characters)
• GSM-7: the basic character set that allows 160 characters per segment
• Unicode / UCS-2: the encoding used once an emoji appears, which drops the limit to 70
• Delivery receipt (DLR): the carrier's report that a message reached the handset
• Carrier fee: a per-segment charge passed through from carriers. Ready shows it as a separate line on your bill.
• 10DLC: registered 10-digit local numbers for business texting
• Opt-out: a STOP reply. On Ready, it applies across every campaign.

The practical takeaway

SMS is one kind of text. "Delivered" means the phone received the message, not that anyone read it. Your bill depends on segments, not messages, so check the character count and watch for emoji before a big send. For delivery, registration and clean lists matter more than anything else.

To see segment counts and delivery statuses on real messages, you can create a Ready account. The first 20 one-to-one texts are free (a card on file is required). Send a few test messages to yourself and look at what comes back.