LinkedIn Message vs Conversation Ads — Character Limits
Message ads send a single InMail with 1500-char body and one CTA. Conversation ads use multiple choice CTAs (max 5 buttons, 25 chars each).
LinkedIn Message Ads (formerly Sponsored InMail) and Conversation Ads share a common shell — both arrive in the recipient's Messaging inbox as a sponsored conversation — but the response model is fundamentally different. Message Ads are one-shot: a single 1500-character message body, a 60-character subject line, and one CTA button capped at 20 characters. The recipient either clicks or doesn't. Conversation Ads are branching: the same shell, but the first message presents up to 5 multi-choice CTA buttons (25 characters each) that branch into follow-up messages, each with their own 500-character body and 25-character button options.
For B2B media buyers running account-based marketing campaigns, conversation ads consistently outperform message ads on engagement (typical 2-4x reply rate) but require considerably more copy to script the branching tree. A complete conversation ad with 3 branches needs roughly 5,000 words of copy across all the message bodies and button options.
Subject line: 40 chars visible
Message ads = single 1500-char InMail with one CTA. Conversation ads = branching choices, each 25-char button max.
Verified 2026 limits
| Field | Hard max | Visible before truncate | Warn at |
|---|---|---|---|
| Subject line | 60 | 40 | 35 |
| Message body | 1500 | 500 | 450 |
| CTA button text | 20 | 20 | 16 |
Source: https://www.linkedin.com/help/lms/answer/a420330 · Last verified 2026-04-15.
| Field | Hard max | Visible before truncate | Warn at |
|---|---|---|---|
| Subject line | 60 | 40 | 35 |
| First message | 500 | 300 | 270 |
| CTA button label | 25 | 25 | 20 |
Source: https://www.linkedin.com/help/lms/answer/a423843 · Last verified 2026-04-15.
Decision framework
Use Message Ads when the offer is a single dense download (whitepaper, demo, calendar). Use Conversation Ads when the prospect needs help self-segmenting (industry, role, problem). The conversation flow doubles as a qualification quiz.
FAQ
- How long is the LinkedIn Message Ad subject line?
- 60 characters maximum, with about 40 visible on the inbox preview before truncation.
- How many CTA buttons can a Conversation Ad use?
- Up to 5 in the first message. Each subsequent branch can have its own button set, up to 5 per node.
- What is the open rate for LinkedIn Message Ads?
- Industry benchmarks land in the 30–50% open range. Reply rates are 2–8% for Message Ads, typically 5–15% for Conversation Ads.