The first line
The line people see first. It gives the viewer a reason to read on.
Say what the post is about or what the viewer gets. Keep it honest: the video has to deliver what the line promises.
One thing to know about [your topic].
Free caption generator for short-form video
Say what your post is about and get 6 captions for Instagram, TikTok, YouTube Shorts or Facebook. Each has a first line that hooks, a short body, a call to action and a few tags. It is free, with no signup.
Example captions
Made for “vitamin C serum” on Instagram. Add your own details and press Generate.
- Before and after
First line: Before and after: vitamin C serum.
Before: [your before].
After: [your after].
Here's how it happened.
Call to action: Link in bio.
- Start here
First line: Vitamin C serum: start here.
If you are new to this, you are in the right place.
Here is the simple version.
Questions are welcome.
Call to action: Link in bio.
Press Generate for 6 captions in the tone and platform you pick.
Before you post
How to use a caption
Step 1: Fill the brackets with something true
Lines with [brackets], like [your best tip] or [your result], need your own real details. Never use a number, result or review you cannot back up.
Step 2: Match the caption to the video
The caption should say what the video shows. If the first line promises a tip, the video has to deliver the tip.
Step 3: Cut it down for the platform
Instagram and Facebook can carry a longer caption. TikTok works with fewer lines, and a YouTube Short usually needs only one. Pick the platform first and the tool trims for you.
Step 4: Rotate your angles
Post a tip one day, a story the next, a question after that. The same opener again and again goes stale.
Pick the job
The parts of a caption
Each part has one job. Here is what each does and how the platform changes it.
Example The body
One to three short lines that give the detail: the tip, the story or the steps.
Put the most important line first. If the platform cuts the body, the first line still has to stand on its own.
Example The key point: [your best tip].
The call to action
One clear next step: follow, open the link, comment or save.
Ask for one thing only. The wording changes by platform: YouTube says subscribe, and the link lives in the description.
Example Link in bio.
Length by platform
Instagram and Facebook can carry a fuller caption. TikTok reads best short. A YouTube Short needs the least.
Write for how people watch: quick, often with the sound off. Say the key idea in the video and the first line.
Example Short on TikTok, one line on a Short.
The tone
Plain is direct and simple. Playful is light and casual. Expert is precise and measured.
Match the voice your brand already uses. Switch tone to see the same idea in a different voice.
Example Plain: A common mistake with [your topic].
FAQ
Frequently asked questions
Is the caption generator really free?
Yes. It is free, with no signup, no email and no limit on how many times you generate or shuffle.
Does the caption generator use AI?
No. It fills written templates with your words, so it runs in your browser, answers instantly and sends nothing you type to a server. Contengine itself uses AI to research your brand and make short-form. This free tool does not.
Why do some captions have [brackets]?
Brackets mark details only you know, like [your result] or [your best tip]. The tool never invents numbers, results or reviews. Replace each bracket with something true before you post.
How long should a short-form caption be?
It depends on the platform and the post. This tool keeps three short lines for Instagram and Facebook, two for TikTok and one for YouTube Shorts. Say the main idea in the video itself and use the caption to add one useful detail.
How are the hashtags chosen?
They come from your own words, your brand name if you add one, and a short list for your type of business. They describe the post. They do not promise reach, and the tool never adds tags that claim to boost views.
What does Contengine do with captions?
Contengine learns your brand, plans the hook and the shots, makes the video with its captions and posts it to Instagram, TikTok, YouTube and Facebook. You approve every post, or turn on auto. Reach is organic, with no ad spend. It costs $29/mo per brand billed annually, or $49/mo month to month, and AI usage is billed at cost.
From a free tool to a posting engine
Contengine creates and posts these for you
This tool gives you the words. Contengine does the rest: it learns your brand from one link, makes the short-form video with its captions and posts it to Instagram, TikTok, YouTube and Facebook. You approve each post, or turn on auto, and it gets better every week.
4
platforms: Instagram, TikTok, YouTube and Facebook
$29/mo
billed annually, your first brand
You approve
every post, or turn on auto
At cost
AI billed at provider price, no markup
Format examples of what Contengine makes. The brands shown are examples, not customers.