How to Make Viral Explainer Videos with Free AI Tools (Step‑by‑Step)

Explainer-style videos are quietly dominating YouTube. Simple visuals, strong narration, and clear storytelling are pulling in millions of views in niches like tech, health, internet culture, and even creepy lore. The best part? You can build this kind of channel using free AI tools from start to finish.

This guide walks through the full workflow: picking a niche, generating ideas and scripts with AI, creating visuals, producing a realistic AI voiceover, and editing everything into a clean, fast-paced explainer video.

Pick a Profitable Explainer Niche

Many successful explainer channels focus on a single clear topic and go deep. Examples include:

• Controversial internet topics and online drama
• Creepy monsters, urban legends, and horror lore
• Health and wellness concepts
• Tech breakdowns and gadget explainers
• Animal facts and nature stories

Start by browsing channels in these niches and look at their most-viewed videos. You’re not copying them—you’re using them as inspiration to see what topics and formats resonate.

Choose a niche where:

• Videos get strong views even with a small upload count
• You can see yourself making dozens of videos
• There’s endless topic potential (news, science, psychology, tech, etc.)

Use ChatGPT to Generate Video Ideas and Scripts

Once you’ve picked a niche, AI can handle most of the heavy lifting for ideas and scripting.

Step 1: Feed ChatGPT Your Niche Inspiration

Open a new ChatGPT session and paste in a batch of titles and descriptions from top-performing videos in your niche. Ask ChatGPT to save everything without replying. This gives it a sense of what works in your space.

Step 2: Generate High-Performing Video Ideas

Next, use a structured “idea creation” prompt (you can keep your own template file for this). Paste the prompt into ChatGPT and let it generate around 10 video ideas tailored to your niche, based on the examples you provided.

Pick the idea that feels:

• Clear and curiosity-driven
• Easy to explain visually
• Broad enough to attract a wide audience

Step 3: Turn the Idea into a Full Script

Now use a “script creation” prompt. Paste it into ChatGPT, then:

• Insert your chosen video title/idea where indicated
• Set your desired video length (ideally 8–10 minutes for YouTube; you can test shorter or longer later)

ChatGPT will output a full script in an explainer style: strong hook, fast pacing, clear sections, and simple language. This becomes the backbone of your video.

If you like this workflow, you’ll probably also find this guide useful: how to make high‑RPM finance videos with free AI tools.

Create a Main Topic Image with AI

Explainer videos often use a single, detailed image that visually represents all the key topics in the video. You can create this with AI and reuse it as both a visual element and your thumbnail.

Step 1: Extract Topics from Your Script

Use an “image creation” prompt in ChatGPT. Paste your full script and ask it to:

• Identify the main topics and concepts
• Generate a single text-to-image prompt that includes all of them in one cohesive scene

Step 2: Generate the Image with Flow

Use an AI image tool like Flow:

• Paste the prompt from ChatGPT into the image prompt field
• Enable image creation
• Set the aspect ratio to 16:9 (YouTube standard)
• Choose an optimized model (e.g., “Nano Banana Pro” in the example)

Generate the image, then download it at the original size. This image will:

• Act as your main “topic map” visual inside the video
• Double as a thumbnail to save time

If you enjoy this kind of visual-heavy workflow, you might also like learning how to bulk-create stylized videos with free AI tools.

Collect Supporting Visuals (Images, Clips, Graphics)

Now you’ll build out the rest of your visuals to match the script line by line.

Step 1: Use Free Stock Sites for Photos and Video

Start at the top of your script and move through it in small sections. For each part, ask: “What’s the simplest visual that represents this idea?”

Use a free stock site like Pixabay:

• For photos: search keywords like “room,” “city street,” “forest,” “brain,” “crowd,” etc.
• For videos: switch to the video tab and search the same keywords

Download any assets that match your script. Since these are free, you can experiment and grab multiple options.

Step 2: Use Canva for Simple Graphics

For abstract or illustrative concepts (like “foggy brain” or “glitching memory”), Canva is great:

• Create a new 16:9 design
• Go to Elements and search for your keyword (e.g., “foggy brain,” “neuron,” “signal,” “timeline”)
• Choose free graphics that fit your style
• Scale and position them on the canvas

When downloading:

• Use the largest size available on the free plan
• Enable transparent background so you can overlay the graphic on other visuals in your editor

Repeat this process for your entire script until every section has at least one matching visual (photo, clip, or graphic).

Generate a Realistic AI Voiceover

Next, you’ll turn your script into a clean, professional-sounding narration using AI text-to-speech.

Step 1: Paste Your Script into Dubdub

Use a tool like Dubdub’s AI voiceover feature:

• Copy your full script from ChatGPT
• Paste it into the script field
• Remove extra blank lines or gaps so the voiceover flows smoothly

Step 2: Choose and Tweak a Voice

In the voice selection panel:

• Filter by “ultra quality” (or similar) for the best-sounding voices
• Preview a few options and pick one that fits your niche (calm for educational, energetic for storytelling, etc.)

In the example, a voice named “Liam” is used—a popular choice for explainer-style content. You can also adjust:

• Speed (slightly faster works well for YouTube explainers)
• Pitch (subtle tweaks only, to keep it natural)

Generate the voiceover, listen through a sample, and if you’re happy, export it as an MP3.

Edit Your Explainer Video in CapCut

With your voiceover, main topic image, and all supporting assets ready, it’s time to assemble everything into a polished video. A free editor like CapCut works perfectly for this style.

Step 1: Build the Base Timeline

In CapCut:

• Import your voiceover, main topic image, and all visuals
• Drag the voiceover onto the main timeline
• Manually trim out long silent gaps by cutting and sliding clips together (leave small natural pauses)

Step 2: Use the Main Topic Image as Section Intros

At the start of the video, place your main topic image on the video track and trim it to cover the opening hook.

Add simple motion using keyframes:

• At the start: set a scale and position keyframe
• Near the end: zoom in (e.g., to 180%) and reposition to focus on the topic being discussed
• Apply easing to smooth the animation

Later, whenever the script moves to a new major topic, copy this image, paste it at the start of that section, and reposition the zoom to highlight the relevant part of the image.

Step 3: Lay Out Your Scene on a White Background

For the main body of the video:

• Add a plain white image or background layer that spans the entire voiceover
• On top of this, place your photos, clips, and graphics in sync with the narration

For each script segment:

1. Listen to the voiceover and identify what it’s describing.
2. Drag in a matching asset and trim it to the exact duration of that line or idea.
3. Scale and position it for a clean, minimal look.

Use simple zooms and slide-in animations via keyframes or built-in animation presets (e.g., “slide up” for a graphic entering the scene). Keep movements subtle and consistent.

Step 4: Add Text Overlays for Key Phrases

To make the video more engaging and easier to follow, highlight important words or short phrases as on-screen text:

• Add a text layer exactly where the word or phrase is spoken
• Trim the text clip so it appears only during that moment
• Choose a clean, readable font and enable shadow for contrast
• Use larger size or color accents for emphasis (e.g., making one key word red)

This works especially well for:

• Definitions (“Deja vu”)
• Emotional words (“familiar,” “glitching,” “already happened”)
• Key conclusions or warnings

Step 5: Combine and Smooth the Ending

When the full video is laid out:

• Select all visual layers above the voiceover
• Group or merge them into a single compound clip
• Add a simple “fade out” animation at the end for a clean finish

Finally, export your video using optimized settings for YouTube (1080p, high bitrate, standard frame rate like 24/30 fps). Your explainer video is now ready to upload.

Turn This Workflow into a Repeatable System

Once you’ve gone through this process once, you can turn it into a repeatable pipeline:

• Niche → idea list with ChatGPT
• Idea → script with a reusable prompt
• Script → main topic image + supporting visuals
• Script → AI voiceover
• Assets → CapCut edit with simple, consistent animations

With practice, you can go from idea to finished explainer video in a fraction of the time it would take to do everything manually—and you can do it using only free AI tools.

If you’re exploring AI as a way to build income-generating content, you may also want to see a broader overview of profitable tools in this breakdown of money-making AI tools.