January 20, 2025 · 5 min read

How to Repurpose Your Substack Newsletter as YouTube Shorts and Instagram Reels

Substack writers pour time and ideas into newsletters that land in inboxes and disappear. The same ideas — packaged as short-form video — can reach millions of people who will never subscribe to an email list. Here's how to bridge the gap without starting from scratch.

If you write for Substack, you already have everything you need to build an audience on YouTube Shorts, Instagram Reels, and TikTok. Every post you've published is a script waiting to be turned into a video.

The Problem With Staying Only in Email

Substack's native discovery is improving, but it's still limited compared to algorithmic platforms. A YouTube Short or Instagram Reel with the right hook can get shown to tens of thousands of non-subscribers in 24 hours. Email can't do that.

The most successful Substack writers use short-form video as their top-of-funnel: they reach new audiences on video platforms, and the Substack newsletter becomes the conversion goal — the place where serious readers go deeper.

Writers like Lenny Rachitsky, Packy McCormick, and Anne-Laure Le Cunff have all expanded from newsletters to video to grow their subscriber bases. The pattern is consistent: video first, email capture second.

Which Substack Posts Work Best as Short-Form Video

Not every post translates equally well. The strongest candidates for short-form video are:

Opinion pieces with a clear point of view — a strong take drives shares and comments on video platforms
Frameworks and mental models — "I use this 3-step framework to..." performs consistently across niches
Counterintuitive insights — surprising or contrarian takes hook viewers in the first 2 seconds
Numbered lists from deep-dive posts — extract "5 things I learned from..." even if the post itself is long-form analysis

Substack posts that are purely personal updates or community announcements don't translate as well — but that's a small subset of most writers' back catalogues.

How to Convert a Substack Post to a YouTube Short

Every Substack post has a public URL (even if the full content is paywalled, the post page is accessible). This is all Supareels needs.

Go to your Substack post and copy the URL from your browser (e.g. yourname.substack.com/p/post-title).
Open Supareels and paste the URL into the Create New Reel field.
Select your caption style — for newsletter-style content, clean minimal captions tend to perform better than flashy animated ones.
Choose a voice that matches your newsletter's tone. If your writing is analytical, a calm measured voice works. If it's energetic and personal, pick something warmer.
Generate. Supareels reads the post, distils it into a 45–60 second script, generates narration and matching AI imagery, and produces a 9:16 vertical video.
Download the video and upload it to YouTube Shorts, Instagram Reels, or TikTok.

Optimising Your Video Caption for Discovery

The caption you write when posting the video matters as much as the video itself. For YouTube Shorts and Instagram Reels:

Put the core idea in the first line — this is what shows in feed before the viewer expands
Add 3–5 relevant hashtags (not 30 — that signals spam on most platforms now)
Include a soft call-to-action: "Full breakdown in my Substack — link in bio"
Tag your Substack in the caption if the platform allows links (most don't in-video, but bio links work)

Building a Cross-Platform Funnel From Your Substack

Think of short-form video as the top of a funnel that ends with a Substack subscription. A typical flow looks like:

Viewer discovers your Reel or Short from an algorithmic recommendation
They find the idea interesting enough to check your profile
Your bio says: "I write about [topic] on Substack — link below"
They click through, read one post, and subscribe

Writers who run this system consistently report 20–50 new Substack subscribers per month from short-form video alone — without any paid promotion.

Automating the Workflow

If you publish on Substack weekly, you can create a standing habit: as soon as a post goes live, immediately paste the URL into Supareels and generate a Short. It takes under 5 minutes including download and upload.

Supareels' Premium plan includes auto-generation, which can watch an RSS feed and create videos from new posts automatically — removing even the 5-minute step.

Your Substack archive is an asset. Put it to work. Start free on Supareels — your first reel from any Substack post is included at no cost.