Free tool · Captions
Instagram caption generator
Describe your post and get 5 Instagram captions with a strong first line and hashtags that fit: 1 free run a day on GPT-6 Luna, no account needed. Pick fun, minimal, witty, heartfelt or promotional.
1 free run a day, no account needed
GPT-6 LunaBy running it, you agree to the Terms and Privacy Policy and confirm you’re 18 or older. We keep what you send and its answer for 7 days, or in your account if you sign up.
Test runs checked . Updated .
Instagram caption generator: three examples
Three inputs and the captions a free run gave each, made once on September 28, 2026 with GPT-6 Luna and shown as it came back. The example buttons in the box above show the same.
Sunset photo from the cliffs at Varkala, Kerala, on the last evening of a week-long trip with my college friends.
1. One last sunset, a thousand memories. Watching the sky turn gold from the cliffs at Varkala, Kerala, with my college friends after a week together. 2. Varkala gave our trip the perfect final frame. College friends, cliffside views, and one last Kerala sunset. 3. The best trips end with everyone in the frame. Saying goodbye to a week with my college friends as the sun set over Varkala’s cliffs. 4. A week of stories, wrapped in a Varkala sunset. Grateful for my college friends and this last evening on Kerala’s cliffs. 5. Our final evening in Kerala went out in color. One last cliffside sunset at Varkala with my favorite travel crew. Hashtags: #Varkala #Kerala #VarkalaCliff #SunsetViews #CollegeFriends #TravelMemories #KeralaDiaries
Our café's new seasonal drink: a pumpkin spice oat latte, out this Friday, 10% off for the first week.
1. Fall’s coziest sip lands this Friday! Try our new pumpkin spice oat latte and enjoy 10% off during its first week. Stop by and get yours. 2. Your first taste of fall comes with 10% off. Our pumpkin spice oat latte arrives this Friday—visit us during launch week and sip something seasonal. 3. Pumpkin spice, oat milk, and a little launch-week treat. Get 10% off our new latte starting this Friday—come by the café and try it. 4. Meet your new Friday favorite: the pumpkin spice oat latte. It’s here this Friday, with 10% off for the first week. Drop in and order yours. 5. Make room for a cozier coffee break! Our seasonal pumpkin spice oat latte launches this Friday, and it’s 10% off all week one. Visit us to celebrate. Hashtags: #PumpkinSpice #OatLatte #SeasonalDrinks #CafeLaunch #CoffeeLovers #FallSips
Mirror selfie after my first 10K run at 42, a year after I couldn't run for five minutes.
1. One year ago, five minutes felt impossible. Today, at 42, I finished my first 10K—and I’m letting myself feel proud. 2. This mirror selfie holds a whole year of showing up. From struggling to run five minutes to crossing my first 10K at 42: I did that. 3. For the version of me who thought running five minutes was out of reach: we made it to 10K. First one, at 42, and it means everything. 4. Not just a finish line—proof of a year of patience, persistence, and finding my way back to myself. First 10K at 42. 🥹 5. A year ago, I couldn’t run for five minutes. Today’s mirror selfie says the rest: first 10K, age 42, heart full. Hashtags: #First10K #RunningJourney #ProgressNotPerfection #42AndRunning #ProudMoment #OneYearStronger
Which AI model is best at this? We tested every one
In our test runs of 5 Instagram caption generator inputs on 17 models, GPT-6 Luna, GLM 5.3 Flash, DeepSeek V4.1 Flash and 12 more passed the most: 5 of 5. That includes GPT-6 Luna, the model a free run is on.
Run on September 29, 2026: 5 inputs on 17 models, each with this tool's own instructions.
| Model | Passed | Hard ones | Messages used on Pro | Cost per run | Time per run |
|---|---|---|---|---|---|
| GPT-6 LunaOpenAIThe free run's model | 5 of 5 | 2 of 2 | 1 each, of 60 a day on Pro | $0.0001 | 5.7 s |
| GLM 5.3 FlashZ.ai | 5 of 5 | 2 of 2 | 1 each, of 60 a day on Pro | $0.0001 | 2.6 s |
| DeepSeek V4.1 FlashDeepSeek | 5 of 5 | 2 of 2 | 1 each, of 60 a day on Pro | $0.0005 | 1.9 s |
| Gemini 3.8 FlashGoogle | 5 of 5 | 2 of 2 | 1 each, of 250 a month on Pro | $0.0005 | 1.8 s |
| Claude Haiku 4.5Anthropic | 5 of 5 | 2 of 2 | 1 each, of 250 a month on Pro | $0.0014 | 3.0 s |
| DeepSeek V4 ProDeepSeek | 5 of 5 | 2 of 2 | 1 each, of 250 a month on Pro | $0.0081 | 10.7 s |
| Grok 4.7xAI | 5 of 5 | 2 of 2 | 1 each, of 250 a month on Pro | $0.0113 | 26.0 s |
| GPT-6.1 SolOpenAI | 5 of 5 | 2 of 2 | 1 each, of 125 a month on Pro | $0.0014 | 4.1 s |
| GPT-6 SolOpenAI | 5 of 5 | 2 of 2 | 1 each, of 125 a month on Pro | $0.0017 | 3.2 s |
| Kimi K3Moonshot | 5 of 5 | 2 of 2 | 1 each, of 125 a month on Pro | $0.0027 | 28.2 s |
| Claude Sonnet 5Anthropic | 5 of 5 | 2 of 2 | 1 each, of 125 a month on Pro | $0.0039 | 4.5 s |
| Claude Sonnet 5.5Anthropic | 5 of 5 | 2 of 2 | 1 each, of 125 a month on Pro | $0.0045 | 4.0 s |
| Gemini 3.1 Pro (preview)Google | 5 of 5 | 2 of 2 | 1 each, of 125 a month on Pro | $0.0089 | 12.1 s |
| GPT-6 AstraOpenAI | 5 of 5 | 2 of 2 | 1 each, of 31 a month on Pro | $0.0071 | 9.6 s |
| Claude Fable 5.1Anthropic | 5 of 5 | 2 of 2 | 1 each, of 31 a month on Pro | $0.0221 | 7.5 s |
| GLM 5.3Z.ai | 4 of 5 | 2 of 2 | 1 each, of 250 a month on Pro | $0.0014 | 1.8 s |
| Claude Opus 5.5Anthropic | 4 of 5 | 2 of 2 | 1 each, of 62 a month on Pro | $0.0205 | 10.4 s |
Side by side: five short captions
The same input on GPT-6 Luna and GLM 5.3 Flash, as each answered it, unedited.
Write 5 Instagram captions for this post, numbered, each at most 40 words with a strong first line, then a "Hashtags:" line. Make them minimal: short, calm, few words. --- A flat lay of my handmade linen napkins in sage green, sold in my Etsy shop.
1. Sage, simply. Handmade linen napkins, now in my Etsy shop. 2. A softer table starts here. Sage green linen napkins, handmade and waiting in my Etsy shop. 3. Calm, folded in linen. Find my handmade sage napkins on Etsy. 4. A little green for the table. Shop handmade sage linen napkins on Etsy. 5. Made by hand, meant for slow meals. Sage linen napkins are in my Etsy shop. Hashtags: #HandmadeLinen #LinenNapkins #SageGreen #SlowLiving #EtsyFinds #TableSetting
1. Sage green linen, folded by hand. Calm starts at the table. 2. Washed linen in sage. Soft, simple, made to be used daily. 3. Every napkin cut and stitched in my studio. Small-batch linen for slow meals. 4. Sage linen napkins. Quiet details that make dinner feel intentional. 5. Handmade linen in sage green, ready to ship. Find them in the Etsy shop 🌿 Hashtags: #linennapkins #sagegreen #handmadelinens #slowliving #etsyseller #tablesetting #slowlivinghome #linenlove
How the inputs are scored
- Key facts: the answer must state each fact the input turns on (a number, a name, a date or a condition), as the input gives it, keep any format rule the input sets (one sentence, a word limit, a number of items, a length for each), and say nothing the input rules out (an ingredient, a claim it doesn't back); how it's worded isn't judged.
The inputs: a bakery's new bun, a birthday climb, no hashtags, when asked, five short captions, and an offer's numbers, exact. Every model gets the tool's own instructions and up to Pro's reply limit. The method is the same as our other test runs.
How to use the Instagram caption generator
Describe the post: what's in it, where, and why it matters to you (or what you're selling). Up to 600 characters.
Pick a tone, whether you want hashtags, and the language.
Press “Write captions”. Without an account you see the first ones (1 free run a day, no account needed).
Pick one, make it sound like you, and post.
Tips for a better answer
Give it the story
“Our first market stall, it rained all morning and we still sold out” gives five captions to work with. “Market day” gives five clichés.
Ask your followers something
Captions with a question (“Which scent would you light first?”) get more comments than statements.
Make it yours
Read the caption in your own voice. Change one word to one you'd actually say and it stops sounding generated.
Check the hashtags
Swap a few generated hashtags for the ones your niche already uses; they're the ones people follow.
What a good captions looks like
The first line does the work
Instagram shows about the first 125 characters before “more”. The first line should make someone stop: a question, a detail, a feeling, not “Here's a photo of…”.
About this post, not any post
The best caption says something only you could say about this post: the place, the person, the moment. Five generic captions that fit any sunset aren't five choices.
Hashtags that fit
A few specific hashtags (#austinfoodtrucks) reach more of the right people than thirty broad ones (#food #love). Look for the ones people in your niche actually use.
A reason to reply
A shop's caption should end with what to do next (“link in bio”, “tag someone who…”); a personal one doesn't need to.
What's free, and what signing up adds
Without an account: 1 free run a day, on GPT-6 Luna, shared with the free message on our home page. It takes up to 600 characters, writes up to about 600 tokens (roughly 450 words), and shows you the start of the captions.
Signing up is free, with an email link and no card. llmwise accounts are for people 18 and older. The captions you ran comes with you as your first chat, and you get 5 free messages on almost every model (all but Claude Fable 5.1, Claude Opus 5.5, and GPT-6 Astra).
Signed in, the tool runs on the model you pick, on your plan, shows the whole answer, and you can carry on in the chat with any model, or ask another model the same thing.
More free tools are on the tools page, and what each plan gives is on pricing.
Questions
Is the Instagram caption generator free?
Yes. Without an account you get 1 run a day on GPT-6 Luna, shared with the free message on our home page: you see the first captions, and the rest when you sign up. Signing up is free and adds 5 free messages on almost every model in llmwise (all but Claude Fable 5.1, Claude Opus 5.5, and GPT-6 Astra), with no card.
Can it look at my photo?
Not in a free run, which reads your description. Signed in, attach the photo to a model that reads images and ask for captions for it.
Does it add hashtags?
Each set ends with 5 to 10 hashtags that fit the post. Pick “No hashtags” if you add your own.
Does it work for Reels and TikTok?
Yes: the captions are short enough for a Reel or a TikTok too. Mention the platform and it adjusts the call to action.
Which AI writes the best captions?
Our test runs below gave every model the same five posts and checked that its captions kept the post's details, stayed short, and came with hashtags when asked.
Which AI is best for this, in your tests?
In our test runs of 5 Instagram caption generator inputs on 17 models, GPT-6 Luna, GLM 5.3 Flash, DeepSeek V4.1 Flash and 12 more passed the most: 5 of 5. That includes GPT-6 Luna, the model a free run is on. The table on this page has every model's result, what a run counts as on Pro, and the time it took.
Claude, GPT, Gemini, DeepSeek, Grok, Kimi, and GLM, in one chat.
See what a message costs before you send it. Free is 5 messages to try; sign in with an email link, no password or card.