How to Make YouTube Shorts from Long Videos (Step-by-Step)

YouTube Shorts have exploded in popularity, with over 70 billion daily views and counting. For creators with existing long-form content, Shorts represent a massive opportunity to reach new audiences without creating content from scratch. The challenge? Manually cutting, cropping, and captioning clips is tedious and time-consuming.

In this guide, we'll walk through the fastest way to turn any long YouTube video into engaging Shorts using AI — from finding the best moments to adding animated captions and publishing.

Why Turn Long Videos Into Shorts?

Before we dive into the how, let's talk about the why. YouTube Shorts appear in a dedicated feed, in search results, and on your channel page. They reach viewers who might never find your long-form content. The algorithm favors Shorts with high watch-through rates, which means well-clipped highlights from your best content can outperform original Shorts.

• Grow your audience: Shorts reach viewers outside your subscriber base through the Shorts feed
• Drive traffic to long-form: Viewers who discover you through Shorts often explore your full videos
• Maximize content ROI: One 30-minute video can yield 5-10 quality Shorts
• Stay consistent: Maintain a daily posting schedule without creating new content every day

Step 1: Choose Your Source Video

Not every video works equally well for Shorts. The best source videos are:

• Talking-head content: Podcasts, interviews, tutorials, and vlogs where someone is speaking to camera
• 5 minutes to 3 hours long: The AI needs enough content to find multiple engaging moments
• Content with clear highlights: Emotional moments, surprising facts, hot takes, or actionable tips

Videos with background music only or purely visual content (like B-roll montages) don't work as well because the AI analyzes the spoken transcript to find highlights.

Step 2: AI Highlight Detection

This is where AI saves you hours of work. Instead of scrubbing through the entire video manually, an AI clip generator analyzes the full transcript and scores every segment for viral potential.

Here's what the AI looks for:

• Emotional peaks: Moments where the speaker's tone shifts — excitement, surprise, conviction
• Hook potential: Opening statements that grab attention ("Here's what nobody tells you about...")
• Topic completeness: Segments that make sense as standalone clips with a clear beginning and end
• Pacing: Faster-paced segments tend to perform better in short-form

With Shortzly's YouTube Shorts maker, you paste your YouTube URL and the AI handles everything: downloading, transcribing, analyzing, and scoring. Each detected highlight gets a 1-10 viral score so you can prioritize the best ones.

Step 3: Crop to 9:16 Vertical Format

YouTube Shorts require 9:16 vertical format (1080x1920). When your source video is 16:9 landscape, simply cropping the center often cuts off the speaker. That's where face tracking comes in.

Good face tracking keeps the speaker centered in the vertical frame throughout the clip. There are two main approaches:

• OpenCV (fast): Uses Haar Cascade face detection. Fast and reliable for single-speaker content
• MediaPipe (accurate): Uses Face Mesh with lip-activity scoring. Better for multi-speaker content where it needs to track the active speaker

Learn more about face tracking in our detailed guide on AI face tracking for vertical video.

Step 4: Add Animated Captions

Captions are essential for Shorts. Most viewers watch with sound off, and studies show captions can boost watch time by up to 40%. But plain subtitles don't cut it — you want trending animated styles.

The most popular caption styles for Shorts include:

• CapCut-style word-by-word: Words appear and disappear one at a time — the most popular style on TikTok and Shorts
• Karaoke: Text fills with color as words are spoken
• Typewriter: Words fade in sequentially
• Bounce: Words scale in at 130% then settle to normal size

Check out our auto caption generator for more details on caption styles and customization options.

Step 5: Review and Customize

AI does the heavy lifting, but you should always review the clips before publishing. Here's what to check:

• Trim points: Does the clip start with a strong hook? Does it end cleanly?
• Face tracking: Is the speaker properly framed throughout?
• Caption timing: Are the captions synced correctly with speech?
• Context: Does the clip make sense without the surrounding video?

Shortzly's waveform editor lets you adjust trim points visually, and you can swap caption styles, colors, and face tracking modes before rendering.

Step 6: Publish to YouTube Shorts

Once you're happy with your clips, download them and upload to YouTube. To be classified as a Short, your video must be:

• 60 seconds or less
• Vertical format (9:16)
• Include #Shorts in the title or description (optional but recommended)

Tips for Maximum Performance

• Hook in the first 2 seconds: The Shorts feed is all about scroll-stopping. If viewers don't engage immediately, they swipe past
• Post consistently: 1-3 Shorts per day is the sweet spot for most creators
• Test different highlights: The AI might score a clip as 7/10, but it could outperform an 8/10 — audience taste varies
• Use brand templates: Consistent watermarks, caption styles, and intro hooks build brand recognition

Get Started

Ready to start turning your long videos into Shorts? Create a free Shortzly account and try it with your first video. The free plan supports videos up to 10 minutes — enough to test the workflow and see the quality for yourself.