Social Media Caption Prompts for Different Platforms

A caption that works on LinkedIn would die on TikTok, and a TikTok hook posted to Facebook reads like a typo. Each platform has its own rhythm, audience, and unwritten rules. The good news: once you teach AI those rules inside your prompt, you can generate platform-perfect captions in seconds rather than minutes.

1. Introduction

Most people write one caption and paste it everywhere. That is the social media equivalent of wearing the same outfit to a wedding, a beach, and a job interview — technically possible, but rarely the right choice. Platforms reward different behaviours, reach different audiences, and impose different character limits. A great prompt builds those constraints in so the AI does the platform-thinking for you.

This tutorial walks through prompt patterns for the five platforms most content teams use day to day: LinkedIn, Instagram, X (formerly Twitter), Facebook, and TikTok. You will end with a reusable mental checklist and several plug-and-play prompts.

2. The Concept Explained

Every platform shapes caption strategy through three levers: character limit, audience intent, and format expectation. Get one wrong and the caption underperforms even if the words themselves are good. Get all three right and average copy still gets engagement.

Think of platforms like neighbourhoods. LinkedIn is the business district — people are dressed for work and want professional insight. Instagram is the gallery district — visuals lead and captions add feeling. X is the town square — short, sharp, opinionated. Facebook is the family living room — warm, story-driven, longer is fine. TikTok is the open-mic night — playful, raw, hook-first. You would not deliver the same line of dialogue in all five places.

3. The Problem Without This Technique

Without platform constraints in the prompt, AI defaults to a generic mid-length caption that suits nowhere.

Write a social media caption about our new yoga app.

4. The Solution

Brief AI per platform — or ask it to produce one version for each platform in a single prompt. Below is a multi-platform prompt for the same launch announcement.

Act as a social media copywriter who has shipped campaigns
across LinkedIn, Instagram, X, Facebook, and TikTok.

Product: "BreathBox" — a 7-minute morning yoga app
for absolute beginners. Launches Monday. Free for the
first 30 days.

Audience: Adults 30–55 who have tried and quit yoga
because longer classes felt intimidating.

Write ONE caption per platform, tailored as follows:

LinkedIn (700–900 chars):
- Open with a personal observation about habit-building
- Connect to the product without sounding salesy
- End with one open question to invite comments
- No hashtags

Instagram (120–180 chars):
- Visual-first; assume a video of someone stretching
- Use line breaks for rhythm
- 3 relevant hashtags at the end

X (≤ 240 chars):
- Sharp, opinionated, one idea only
- No hashtags
- Can be a single sentence

Facebook (200–300 chars):
- Warm, story-led
- Mention the free trial naturally
- End with a soft CTA, no emoji

TikTok (≤ 140 chars):
- Casual, hook-first
- Pair with an implied trend ("POV:" or similar)
- 2 hashtags max

5. Step-by-Step Breakdown

1. Name the platform. Always. The platform shapes everything else — length, tone, hashtag use, emoji policy.
2. Set the character or word limit. Use a hard upper bound so the AI does not "round up" into a longer caption.
3. Specify hook style. "Open with a question", "open with a confession", "open with a statistic" — the first line decides whether anyone reads the rest.
4. State hashtag policy. None, two, three, or "use 5 niche hashtags" — be explicit. AI tends to over-hashtag if left to its own devices.
5. Define emoji policy. "No emoji" or "one emoji maximum" or "emoji-heavy for TikTok" — choose deliberately based on brand voice.
6. Ask for one CTA, never two. Multiple CTAs split attention. Choose: comment, save, click, share — one per caption.

Tip: Captions live and die on the first line. After AI gives you a draft, ask:

Rewrite just the opening line in five different styles — question, confession, statistic, contrarian take, and short story.

Pick the strongest, then keep the rest.

6. Practice Exercises

Rewrite the LinkedIn caption you just produced as a 5-line carousel post, with one line per slide and a final slide that is just a CTA.

7. Key Takeaways