The caption is where many profiles stall. The photo is taken, the product is in hand, and the post sits in drafts for days because "I don't know what to write". A caption generator solves that, but each one solves it differently: some depend on what you explain in each request, some already know your niche, and a few deliver the caption together with the whole post.
Prices checked on September 18, 2026, on monthly billing, each linked to the page it came from. For ChatGPT we used the official app page on the US App Store, where the price is public.
The 7, side by side
| Tool | How it writes the caption | Starting price (monthly) | Free? |
|---|---|---|---|
| ZapPost | Caption with a CTA, tuned to your niche, delivered with the carousel and script | US$19/mo (Monthly) | 7-day guarantee |
| ChatGPT | You describe the post and ask; the result depends on your prompt | Free; Go at US$8/mo in the app | Yes |
| Copy.ai | Chat with OpenAI, Anthropic and Gemini models | US$29/mo (Chat, 5 users) | Not shown on the pricing page |
| Jasper | Writes in your registered brand voice, built for teams | US$69/mo per user (Pro) | No, 7-day trial |
| Predis.ai | Generates caption and hashtags with the post, on credits | US$32/mo (Core, 1,300 credits) | No, 7-day trial |
| Ocoya | Generates text and images on credits, schedules in the same panel | US$29/mo (Starter, 300 credits) | No, 7-day trial |
| Lately | Slices your long content (text, audio, video) into many posts | US$19/mo (Starter) | No, free try |
Caption together with the post: ZapPost, Predis.ai and Ocoya
A caption alone is half the trip: the visual is still missing. ZapPost delivers the complete post: you say the topic in the Studio and get the assembled carousel with the script and a caption with a CTA, already in your niche's tone. It costs US$19 a month on the Monthly plan. In practice, your niche is set up once, from your profile's @, and every caption comes out with that context. One limit to know: the plan allows a set number of text generations per day, and each AI-made image uses credits.
Predis.ai and Ocoya also generate caption and visual, on credits: you request each post and review it. The comparison with a general-purpose AI is in ZapPost vs ChatGPT.
The free one that works: ChatGPT, on one condition
For occasional posting, free ChatGPT does the job. The condition: the caption comes out the size of your request. "Write a caption about a promotion" gets you a caption that would fit any store in the country. Saying who the customer is, what the offer is and what the reader should do at the end changes the result. The context of your business comes from what you write in the request.
The good-caption test: cover the profile name and read the caption alone. If it could belong to any competitor of yours, send it back to the AI with more context. A good caption has your customer and your offer inside it.
For people who write in volume: Copy.ai and Jasper
The Chat plan at Copy.ai gives you OpenAI, Anthropic and Gemini models for US$29 with 5 seats, useful when captions are one of many copy jobs. Jasper is the priciest of the list at US$69 per user on Pro, which includes 2 brand voices. It earns that when a whole team needs to write in one voice. For a single profile, it is a cannon aimed at a fly.
The special case: Lately
If you record a podcast or long videos, Lately slices that material into many posts for US$19 on Starter. Without long content to feed it, it has no raw material, so it only makes the list for people who already produce.
What 476 carousels show about captions
In our reference base, collected in August 2026 with 476 carousels from 118 niche profiles, each with at least 10 comments, half of the captions run up to 370 characters, about 60 words. And 53% of the posts use no hashtag at all. One example from the short end: this carousel from a Brazilian nutrition profile has a one-line caption and had over 800 comments when we collected it. If you are stuck thinking you need a long text, start with a short one.
How to choose
- Want the caption already inside a finished post, for your niche? ZapPost. Predis.ai and Ocoya do it per request.
- Post rarely and enjoy writing prompts? Free ChatGPT.
- Write in volume or as a team? Copy.ai, or Jasper when brand voice is critical.
Want to try one with no card and no sign-up? We keep a free caption generator, with hand-written captions for 8 professions.
If your problem comes before the caption, at "what should I even post", that is another path: we keep post ideas by profession, and a guide on the best apps to create posts.
ZapPost delivers the carousel, the Reels script and the caption ready to go. No writing prompts, no Canva, no new tool to learn. You review and publish.
Frequently asked questions
Is there a completely free caption generator?
ChatGPT has a free plan. ZapPost's free caption generator has ready captions for 8 professions, with no sign-up. The generators that deliver the caption together with the post charge a subscription, with a trial or a guarantee instead of a free tier.
Does Instagram punish AI-written captions?
The AI labeling rule Meta announced covers AI-generated images, video and audio. Text captions are not in it. What matters is reviewing the caption and adding your business context before you publish.
Do captions still need hashtags in 2026?
Since December 18, 2025, Instagram allows up to 5 hashtags per post or Reel, according to the announcement from the official @creators account. In our base of 476 carousels, 53% used none. Predis.ai and Ocoya suggest hashtags; in ZapPost the caption comes with a CTA.
What is the ideal caption length?
It depends on the post. An educational carousel works with a short caption, because the content lives in the slides: in our base, half of the carousel captions run up to 370 characters. A single photo asks for a caption that tells the story. The first line decides whether anyone taps "more", so start with the hook.