Free AI Video to Shorts — No Signup, No Watermark, Browser-Based
Turn any long video into vertical shorts with word-highlight captions — free, no signup, no watermark, no credit card. Processes 100% in your browser (your video never leaves your device). Outputs 1080×1920 MP4 clips ready for TikTok, Instagram Reels, YouTube Shorts, LinkedIn, and X.
OpusClip, Submagic, Vizard, and Klap built an entire category of AI short-form clippers — then packed it with watermark gates, signup walls, 720p ceilings on free tiers, and an "annual price displayed as monthly" pricing trick that doubles your real bill. PromptSpace AI Video-to-Shorts strips all of that out: free forever, zero signup, zero watermark, 1080×1920 output on the free tier, and your video never gets uploaded to our servers because the entire pipeline runs inside your browser.
How we built it differently: ffmpeg.wasm (compiled to WebAssembly, the same stack ships in VideoConverter and GifMaker elsewhere on PromptSpace) cuts your source video, re-encodes to 9:16, and burns the word-highlighted karaoke captions directly on your CPU. Only the extracted audio transcript hits our proxy, which calls Cloudflare Workers AI Whisper for transcription with word-level timestamps. The AI clip-ranking step sends only the transcript (no video) to Gemini via our prompt-optimizer backend. Your source video never leaves your device.
The honest limits of browser-only: ffmpeg.wasm peaks at ~500 MB of browser memory, so we cap source length at 15 minutes and file size at 500 MB. Processing is roughly 1.5× slower than native server-side ffmpeg on the same codec work, but you skip the OpusClip 25-minute "upload-then-wait-in-queue" penalty entirely — time-to-first-clip on a 10-minute source is 30–60 seconds on a modern desktop. Older iPhones (iPhone X and earlier) may hit the memory ceiling; desktop and modern Android phones work great.
What makes our clip-selection different: every competing tool scores clips by "virality" heuristics — loudest moments, strongest emotion, dramatic swings. That optimizes for TikTok sensationalism but produces terrible shorts for educators, interviewers, podcast creators, and anyone doing research or tutorial content. Our prompt lets you specify your topic in the instructions field, and the LLM scores complete-thought segments relevant to your topic over generic drama. This is a documented gap in the OpusClip/Submagic/Vizard product category, verified via Reap Research's April 2026 benchmark of nine paid tools.
For creators who care about pricing fairness: four of the eight top competitors (OpusClip, Submagic, Vizard, Klap) default their pricing page to annual billing and display the annual rate with a "/month" label. Click the Monthly toggle and the real month-to-month price is roughly double. Klap goes from $14 to $29; Submagic from $19 to $38. We don't do that. The free tier is free, period. If and when we add a paid tier (after we see real usage data), monthly pricing will be labeled monthly.
How it works
Three steps from long video to downloadable vertical shorts:
- 1. Upload your video. Drop any MP4, MOV, or WebM up to 15 min / 500 MB. Processing starts instantly in your browser — nothing uploads to our servers.
- 2. AI picks the best moments. Optionally add a topic. The AI reads the transcript and picks 3 clips that match YOUR topic, not generic "viral" moments. Perfect for tutorials, interviews, and educational content.
- 3. Download vertical shorts. 1080×1920 MP4 with word-highlight captions burned in. Pick caption style, pick highlight color, download. No watermark, no account.
Who uses this tool
Podcast repurposing
Turn a 60-minute podcast into 10 vertical clips without hiring an editor. The AI picks complete-thought segments matching your topic.
Course and tutorial clipping
Educators get clips that teach a concept, not just loud moments. The instructions field is a game-changer for educational content.
YouTube to Shorts
Clip your own uploaded YouTube videos (download them yourself, we don't help you download other people's content).
Interview highlights
Pull the strongest answer-moments from an interview without scrubbing hour-long files manually.
Webinar + conference shorts
Turn recorded webinars into LinkedIn-ready clips with branded captions.
Sermon and talk clipping
Religious and TED-style talks: get complete-thought shorts that preserve the full idea instead of a loud 3-second peak.
Why use the PromptSpace version
- Zero watermark, free forever. OpusClip, Vizard, Submagic all watermark their free tier output. We do not.
- 100% browser-side (privacy-first). Your video never uploads to our servers. Only the audio transcript (text) reaches our proxy for Whisper transcription.
- Topic-specific clip picking. The only tool in this category that lets you tell the AI what topic you want clips about. Educators and researchers finally get usable output.
- 1080×1920 on free tier. OpusClip and Vizard cap free users at 720p. We ship full 1080p vertical by default.
- No credit metering, no signup. Rate-limited by Turnstile at 2 clips/day. No account, no credit card, no "credits" math.
- MCP skill ships with v1. Claude Code, ChatGPT (Developer mode), Cursor, and Hermes can drive this tool via the PromptSpace MCP server. Only OpusClip and Reap offer agent access, both paywalled.
Pro tips for better results
Fill in the "topic" field
This is the single biggest quality lever. "Clips where I explain how to invest" produces different output than "Clips where I share surprising stats." The AI uses your instruction as the ranking criterion, not a filter — so even a short instruction dramatically improves results.
Pick the right caption style
For talking-head podcasts: Bebas Neue (bold, impact) with word-highlight in yellow. For tutorials: Inter (readable) with highlight in your brand color. For TikTok dance-style content: Poppins (friendly) with highlight in neon.
Use desktop for 10+ minute sources
ffmpeg.wasm memory headroom is better on desktop Chrome / Firefox / Edge. Mobile Safari in particular hits the 500 MB wall faster on long videos.
Download the SRT alongside the MP4
Even if you don't use burned-in captions, the SRT lets you re-caption in CapCut or Premiere with your brand's preferred style — faster than running the whole pipeline again.
Frequently asked questions
Is this really free, no signup, no watermark?
Yes. No account, no email, no credit card. Zero watermark on output. Rate-limited at 2 clips per day per browser (Turnstile) only to prevent abuse — that is the only limit.
Does my video get uploaded to your server?
No. The entire pipeline runs inside your browser using ffmpeg.wasm — video cutting, 9:16 cropping, caption burning, and MP4 encoding all run on your CPU. Only the extracted audio transcript (text) is sent to our proxy for Cloudflare Whisper transcription. Your original video never leaves your device.
How is this better than OpusClip, Submagic, or Vizard?
Ten verified wins (October 2026): (1) zero watermark on free export (OpusClip, Vizard, Submagic all watermark free); (2) no signup required; (3) 1080×1920 output on free (OpusClip + Vizard cap free at 720p); (4) your video stays on your device (every SaaS competitor uploads to their server); (5) ~30–60s TTFC vs OpusClip Pro's 25-min TTFC on a 90-min source; (6) topic-specific clip ranking (we score against YOUR instructions, not generic virality); (7) no annual-pretending-to-be-monthly pricing games; (8) word-highlight captions free (Submagic charges $19–$39/mo); (9) no credit metering; (10) MCP skill ships with v1 for Claude Code / ChatGPT / Hermes.
What are the real limits?
Max 15 min source length, 500 MB file size (ffmpeg.wasm browser memory ceiling). No YouTube URL support in v1. No face tracking (we use stable centered crop with upper-60% bias). 5 built-in caption fonts. Older iPhones may hit memory limits on long videos — desktop recommended for 10+ min sources.
What output formats and resolutions?
MP4 at 1080×1920 (9:16 vertical, default), 1080×1350 (4:5 feed), or 1080×1080 (square). Captions burned into the video so they play correctly on TikTok, Reels, Shorts, LinkedIn, and X. SRT subtitle files download alongside each clip for re-editing.
What languages are supported?
Cloudflare Whisper supports 50+ languages including English, Spanish, Portuguese, Hindi, French, Mandarin, Japanese, Arabic, German, Italian, Russian, Korean, Dutch, Turkish, Vietnamese, Thai, Indonesian, Polish, Ukrainian, and more. Transcription language is auto-detected.
How many clips do I get per video?
3 clips per upload on free tier. Each clip is 20–90 seconds long, picked by the AI based on complete thoughts, strong openings/closings, and (if you provide one) your topic field.
Can I use these commercially?
Yes. You retain full copyright and commercial rights to any clip derived from a video you own or have authorization to process. PromptSpace doesn't claim rights to anything you upload.
When will it be live?
Engine ships within 5 days of 2026-10-21. Enter your email on the waitlist above and we'll notify you the moment it goes live.
Related free tools and prompts
- AI Video Generator — Text → cinematic video with fal.ai.
- AI Voice Generator — Add voiceover to any clip.
- AI Instagram Reel Generator — Full reel from a single prompt.
- AI Image Upscaler — Enhance photos to 4K free.
- MCP Agent Skills Library — 76+ ready-made skills for Claude, ChatGPT, Hermes.
What next?
You just used a free PromptSpace tool. Most users save a prompt for later or browse the prompt library before leaving.