Guide
How to Use Captionstool
From upload to exported video — in three simple steps.
Create a free account
Click Sign inand enter your email address. We'll send you a magic link — no password required. Click the link to land straight in the app. Your account is free and no credit card is needed to get started.
Upload a video & generate captions
On the main screen, click Upload video and select an MP4, MOV, WebM, or MKV file (max 250 MB, max 5 minutes). Captionstool extracts the audio and sends it to Whisper for AI transcription. Within seconds, every word appears in the caption timeline with precise timestamps. You can play the preview, click any word to edit it, and adjust timing directly in the timeline.
Upgrade to Pro & export
When you're happy with the captions, click Export. If you're on the free plan you'll be prompted to upgrade. Pro costs 30 DKK/month and is billed securely via Stripe. After subscribing, hit Export and download your video with captions permanently burned in — ready to post anywhere.
View pricingFrequently Asked Questions
What video formats are supported?
You can upload MP4, MOV, WebM, and MKV files up to 250 MB and up to 5 minutes long.
How accurate is the transcription?
Transcription is powered by OpenAI Whisper, which achieves high accuracy on clear speech in a wide range of languages. Background noise, heavy accents, or overlapping speakers may reduce accuracy. You can always edit any word directly in the timeline after processing.
Can I use Captionstool for free?
Yes. Uploading, transcribing, and editing captions in the timeline are free forever. Exporting the final video with burned-in captions requires a Pro subscription.
How do I cancel my subscription?
Click on your profile in the top right corner to open your account menu, and click the "Cancel Subscription" button. Your subscription will be cancelled immediately, and you will keep your Pro access until the end of your billing period.
Is my video stored on your servers?
No. Videos are processed in a temporary environment and deleted immediately after the caption transcript is generated. We never retain your video files.
What languages does Captionstool support?
Whisper supports transcription in dozens of languages including English, Spanish, French, German, Danish, and many more. Just upload your video — the language is detected automatically.
Can I edit the captions before exporting?
Absolutely. Every word is editable in the caption timeline. You can change text, adjust timing, split or merge lines, and preview the result live before exporting.