Last updated: 2026-08-04

LINE Message Character Limits | Messages, Notes & Profile Guide

LINE is the dominant messaging app in Japan and several other Asian markets, with roughly 100 million monthly active users in Japan alone as of March 2026. Despite its widespread daily use, few people know the exact character limits for each feature. This article provides a comprehensive overview of LINE's character limits across all major features, along with professional tips for maximizing your communication within those constraints.

Surprising Facts About LINE

As of August 2026, LINE's chat message limit is 10,000 characters, but this wasn't always the case. The limit was reportedly lower at launch and has been gradually expanded over time. Another lesser-known fact: LINE limits emoji to a maximum of 20 per message. Heavy emoji users may hit this cap before reaching the character limit.

LINE also offers a "message unsend" feature, but it only works within 24 hours of sending. This serves as a safety net if you accidentally send a message with errors or excessive length.

The Technical Background Behind the 10,000-Character Limit

LINE's 10,000-character cap for chat messages is rooted in the design of its messaging infrastructure. Messages are delivered in real time through LINE's servers, and larger payloads per message increase both server processing load and bandwidth consumption. Under UTF-8 encoding, a single Japanese character occupies 3 bytes, so a 10,000-character Japanese message amounts to roughly 30KB of data. While small compared to images or videos, this is substantial for a text message.

The 10,000-character threshold strikes a balance: it is high enough that users rarely feel constrained, yet low enough to serve as a safeguard against malicious bulk-text attacks that could overload the server. In everyday use, most messages people exchange run from a few dozen to a few hundred characters, making the 10,000-character ceiling virtually irrelevant in practice.

Message Length and Read-Through Rates

LINE's "read" receipt is widely recognized as a delivery confirmation, but there is a clear correlation between message length and actual read-through rates after the receipt appears. Analysis of LINE Official Account delivery data across multiple case studies shows that longer messages consistently lead to higher mid-message drop-off rates.

Specifically, messages under 100 characters maintain a read-through rate of roughly 90% or higher, while messages exceeding 300 characters see that rate drop to around 60–70%. Beyond 500 characters, the rate falls further to approximately 40–50%. The same trend applies to personal chats: long messages are more likely to be set aside for "later" and ultimately forgotten, leading to lower reply rates. Because the read receipt only confirms that the message appeared on screen, senders often mistakenly assume the entire content was read.

LINE Character Limits at a Glance

All limits in this article reflect the specifications as of August 2026 and may change.

LINE VOOM vs. Chat Messages: Same Limit, Different Use Cases

LINE VOOM (formerly LINE Timeline) and chat messages share the same 10,000-character ceiling, but their intended use cases differ significantly. Chat messages are designed for real-time one-on-one or group conversations, where long texts monopolize the recipient's screen and short messages are preferred. LINE VOOM, on the other hand, is a feed-based posting format where followers scroll through content at their own pace, making it far more suitable for long-form writing.

LINE VOOM also supports hashtags, which extend a post's reach beyond existing followers. Hashtags count toward the 10,000-character limit, so you need to budget for both body text and tags. In practice, keeping the body text between 3,000 and 5,000 characters and reserving the rest for hashtags and whitespace formatting tends to yield the best engagement.

LINE Official Account Limits

Why Official Accounts Are Limited to 500 Characters

The 500-character limit for LINE Official Accounts reflects a deliberate UX design choice. Long messages from businesses tend to feel like spam, reducing open and read-through rates. At roughly one minute of reading time, 500 characters is about the maximum that fits on a smartphone screen without scrolling. This constraint forces businesses to focus on their core message, ultimately improving the user experience.

It is worth noting that the 500-character cap applies specifically to text messages. By combining text with other message formats such as rich messages and card-type messages, the effective amount of information you can convey in a single broadcast increases substantially. Each broadcast can include up to 3 message objects (bubbles), and you can freely mix text, images, and cards. Judging the limit as "too short" based on the 500-character figure alone overlooks these possibilities.

Emoji, Stickers, and Special Character Counting

LINE's character counting has several counterintuitive behaviors. LINE's proprietary emoji count as 1 character each, but standard Unicode emoji may internally count as 2 or more characters. For example, flag emoji (such as 🇯🇵) are composed of Regional Indicator Symbol pairs, so a single visible flag can consume 2 or more characters internally.

LINE stickers are sent as separate message objects and do not count toward the 10,000-character text limit. However, you cannot mix text and stickers within a single message; stickers are always sent as standalone messages. LINE emoji are capped at 20 per message, a constraint that is independent of the text character limit.

Line break characters also count as 1 character each. Messages that use frequent line breaks for visual formatting consume more characters than the visible text alone suggests. When composing official account messages within the 500-character limit, factor in the characters consumed by line breaks.

LINE Bot (Messaging API) Character Limits

When developing a LINE Bot via the Messaging API, different character limits apply compared to regular chat messages. The Messaging API caps text messages at 5,000 characters-half the 10,000-character limit of personal chats. This restriction is likely designed to manage API response sizes and server load.

The Messaging API allows up to 5 message objects per request. Beyond text, you can send images, videos, audio, location data, stickers, template messages, and Flex Messages. Flex Messages in particular let you build sophisticated layouts combining text, images, and buttons via JSON definitions, though the total JSON size must stay under 50KB.

Reply messages and push messages both support up to 5 message objects per request. Broadcast messages (sent to all friends at once) follow the same 5-object limit per request.

Common Mistakes When Ignoring Character Limits

• Official account messages getting cut off: Writing beyond 500 characters without checking, then scrambling to trim the text at send time, often resulting in an incoherent message.
• Profile names truncated with "...": Attempting to set a name longer than 20 characters, then awkwardly abbreviating it into something unrecognizable.
• Long messages getting ignored: Sending a 10,000-character wall of text that fills the recipient's entire screen, killing any motivation to read it.
• Important info lost in chat: Posting critical announcements in the chat stream instead of using Notes (which supports 10,000 characters and can be pinned).
• Bot development character-overflow errors: Writing code that assumes the 10,000-character personal chat limit, only to hit the Messaging API's 5,000-character cap. Without proper error handling, messages silently fail to reach users.

Ideal Message Length for Personal Chats

In personal chats with friends and family, brevity matters even more than in business settings. Screen space on a smartphone is limited, so knowing how each length range looks on screen - and the impression it gives - helps you keep conversations flowing.

For casual chats with friends, 20-50 characters is the sweet spot. For messages to teachers or senior colleagues, 50-100 characters strikes the right balance of politeness and readability. When a message starts running long, the same text reduction techniques used in writing work on LINE too.

Most "left on read" situations are also less about message length than about how hard the message is to reply to. Short messages with clear questions and limited reply options get answered faster.

Optimal Message Length for Business Use

For customer-facing communication, keep the initial greeting under 150 characters and split detailed explanations across 2–3 separate messages. Sending several short messages rather than one long block gives the recipient a sense of conversation and tends to improve reply rates.

For LINE Official Account broadcasts, the sweet spot is 200–300 characters. Using the full 500-character allowance risks information overload, while messages under 100 characters can feel too thin. The 200–300 character range conveys your point without excess.

Effective Character Counts for Group Chats

Group chats demand even more attention to message length than one-on-one conversations. With multiple people posting simultaneously, a long message pushes other members' contributions off screen. The recommended length for a single group chat message is around 50–100 characters.

When you need to share lengthy information within a group, the Notes feature is the best option. Notes support up to 10,000 characters, remain accessible without getting buried in the chat stream, and can be referenced by any member at any time. For meeting minutes, travel plans, or event details, write the content in a Note and post a short notification in the chat saying "Details are in the Note."

The larger the group, the more important brevity becomes. In groups of 10 or more, consider whether a message truly needs to reach everyone before sending. Using the mention feature (@name) to address specific members helps reduce notification fatigue for the rest of the group.

Professional LINE Communication Techniques

• The "3-line rule": Keep each message to 3 lines or fewer. For longer content, split into multiple messages. This aligns with the amount of information short-term memory can process at once.
• The "first 14 characters" principle: LINE notification previews show roughly 14–20 characters. Place your most important information within this range to dramatically improve open rates.
• Bubble splitting for official accounts: Instead of one 500-character bubble, use three 150–200 character bubbles. This creates a conversational rhythm that improves read-through rates.
• Strategic emoji placement: Placing emoji at the beginning and end of messages increases visibility in chat lists. Limit to 2–3 per message to avoid looking unprofessional.

Effective Use of Line Breaks

Strategic line breaks dramatically improve readability on LINE. Insert a blank line every 3–4 lines to create visual breathing room on small smartphone screens. For business communications, use bullet points to organize information so recipients can quickly find what they need.

Real-World Example: Effective Official Account Message Structure

To illustrate how to make the most of the 500-character limit, consider a restaurant's LINE Official Account sending a weekly promotion:

• Bubble 1 (~100 characters): A brief greeting plus a spotlight on one featured menu item for the week.
• Bubble 2 (Rich Message): An appetizing photo of the dish paired with a coupon link.
• Bubble 3 (~80 characters): Updated business hours or a reservation prompt.

By combining text, images, and links across multiple bubbles, you can deliver a complete message well within the 500-character cap. Studies suggest that broadcasts containing rich messages tend to achieve higher click-through rates than text-only messages.

Official Account Delivery Techniques

For LINE Official Account operators, understanding character limits is only the starting point; delivery strategy determines results. Open rates fluctuate significantly by time of day. Weekday lunch breaks (12:00–13:00) and evenings (18:00–20:00) are generally the highest-performing windows. Timing short, impactful messages to these slots is the foundational strategy.

Segment delivery lets you send different messages to different user groups based on attributes or behavior history. Rather than blasting the same 500-character message to everyone, sending 200–300 character messages tailored to each segment tends to improve both click-through and conversion rates.

A/B testing allows you to send two message variants-differing in length, wording, or format-to a subset of users first, then deliver the better-performing version to the rest. Testing "short text + rich message" against "long text only" with your own audience data is far more reliable than following generic best practices.

Conclusion

LINE's character limits span a wide range-from 10,000 characters for personal chats to 500 for official accounts and 5,000 for the Messaging API. The 500-character official account cap is tighter than most people expect, so always verify your character count with Character Counter before sending. Message length and read-through rates are clearly correlated: shorter, focused messages consistently achieve higher completion rates. By applying the "first 14 characters" principle and bubble-splitting technique, you can craft messages that resonate with readers even within strict limits.