Free Substack to Social Posts Tool

What is a Substack to social posts tool?

A Substack to social posts tool reads a Substack post and writes posts from it for Substack Notes and the other networks, each in the shape that network rewards.

You write the post once. The tool writes the Notes, the LinkedIn post, the X thread and the rest.

Every number, name, example and quote comes from your post, so you can publish each one as yourself.

A paid post shows only its free part to the reader, so paste the full text for a paid post.

What wins on Substack Notes

On October 1, 2026, I read the public Notes of every Substack writer in my creator directory, up to their latest 300.

Then I compared each note with its own writer's usual likes, so a big account never wins for being big.

Here's how each kind of note did, for the 14 writers with 100 notes or more:

Notes that only pointed to a post did worst. Notes that gave the value right there, a list or a full idea, did best.

So the tool writes 3 Notes for each post:

• One idea: your post's sharpest line, under 300 characters, with no link
• One list: your post's steps or tips as a numbered list, with a first line that says what the list gets the reader
• One share: your post's most specific result, then your link

Post the first 2 for the reach, and the third for the clicks.

The Notes that did best

These are the top notes of 6 writers, with their real likes and how far each beat that writer's usual:

Sahil Bloom

The note's opening

Major cheat code for life: Always assume things will work out, then do the work to make it true.

Likes

15,802

Against usual

42×

Posted

July 2026

Sabrina Ramonov

The note's opening

Anthropic dropped an entire free learning path for Claude AI …9 courses. Beginner to advanced. Zero paywall.

Likes

3,158

Against usual

137×

Posted

May 2026

Justin Welsh

The note's opening

I don't want much in life.I just want to work 3-4 hours per day, help thousands of people …

Likes

1,992

Against usual

5×

Posted

January 2026

Ruben Hassid

The note's opening

Google your name. Now imagine your ex doing it.Four prompts erase what they'd find (for $0):

Likes

1,754

Against usual

24×

Posted

July 2026

Charlie Hills

The note's opening

I turned Claude into an entire company.42 skills, organised like a real org chart (links below):

Likes

1,727

Against usual

82×

Posted

July 2026

Eric Topol

The note's opening

The Shingles vaccine and reduction of dementia: a new natural experiment from Canada replicated 3 others …

Likes

223

Against usual

3×

Posted

January 2026

Writer	The note's opening	Likes	Against usual	Posted
Sahil Bloom	Major cheat code for life: Always assume things will work out, then do the work to make it true.	15,802	42×	July 2026
Sabrina Ramonov	Anthropic dropped an entire free learning path for Claude AI …9 courses. Beginner to advanced. Zero paywall.	3,158	137×	May 2026
Justin Welsh	I don't want much in life.I just want to work 3-4 hours per day, help thousands of people …	1,992	5×	January 2026
Ruben Hassid	Google your name. Now imagine your ex doing it.Four prompts erase what they'd find (for $0):	1,754	24×	July 2026
Charlie Hills	I turned Claude into an entire company.42 skills, organised like a real org chart (links below):	1,727	82×	July 2026
Eric Topol	The Shingles vaccine and reduction of dementia: a new natural experiment from Canada replicated 3 others …	223	3×	January 2026

Their shapes are what the tool copies, never their words. The one-idea note states one claim plainly, the list note names its count up front, and the share note gives a result before the link.

An example

I gave it Substack's own post, A business model that works for creators. Here are the 3 Notes it wrote, as they came:

Note 1
Substack’s native sponsorships program makes great partnerships simple.
It lets creators keep full editorial independence while Substack handles matchmaking and logistics.
The system should serve the people who use it, not the other way around.

Note 2
Here are the flagship partners investing millions of dollars in creators:
1. Yahoo Scout
2. Whatnot
3. Granola
4. Balenciaga
5. T-Mobile
6. Polymarket
7. Uber
These brands are part of the inaugural cohort.

Note 3
The top 10 creators on Substack collectively earn over $100 million a year.
https://on.substack.com/p/a-business-model-that-works-for-creators

The list note carries the post's partners in the note itself, and the share note gives a number before the link.

Compared with Buffer

Buffer has a free Substack to social media post repurposer too. I gave both Shea Serrano's interview on On Substack on October 1, 2026:

Buffer reads more of a long post. Past 9,000 characters, paste the part you want posts from.

Both offer the same 5 tones and switches for hashtags and emoji.

On LinkedIn, Buffer's posts used Markdown bold in 2 of 3 posts, which LinkedIn shows as asterisks, plus an em dash and words like "showcases" and "fosters". It also returned a 4th post that read only ": 250".

On the same post, this tool's 3 LinkedIn versions came back checked, with the post's own numbers: 126,000 views and 10,385 downloads in the first week.

What each platform allows

Substack Notes

Longest post

No published limit

How it counts

Every character

Source

On Substack

Bluesky

Longest post

300 characters

How it counts

Each emoji or accented letter as 1

Source

Bluesky docs

Mastodon

Longest post

500 characters

How it counts

A link counts as 23

Source

Mastodon docs

LinkedIn

Longest post

3,000 characters

How it counts

Every character

Source

LinkedIn Help

X

Longest post

280 characters a post

How it counts

A link counts as 23, an emoji as 2

Source

X's counting rules

Threads

Longest post

500 characters

How it counts

Every character

Source

Instagram Help

Platform	Longest post	How it counts	Source
Substack Notes	No published limit	Every character	On Substack
Bluesky	300 characters	Each emoji or accented letter as 1	Bluesky docs
Mastodon	500 characters	A link counts as 23	Mastodon docs
LinkedIn	3,000 characters	Every character	LinkedIn Help
X	280 characters a post	A link counts as 23, an emoji as 2	X's counting rules
Threads	500 characters	Every character	Instagram Help

Substack's own Notes FAQ dares writers to find the limit, so the tool keeps Notes short on purpose, not to fit a cap.

Every post shows its count the way its platform counts it. Check any text with the X character counter or the Threads character counter.

What it writes for each platform

Platform	What you get
Substack Notes	3 notes: one idea, one list, one share with your link
LinkedIn post	900 to 1,500 characters that open on your post's most specific result
X thread	5 to 8 posts under 280 characters, your link last
X post	1 post under 280 characters
Threads post	Under 450 characters: a result and 2 to 4 lines behind it
Bluesky post	Under 280 characters that end on the takeaway
Mastodon post	Under 480 characters, your link last
Facebook post	400 to 900 characters, steps as a numbered list

Pick 3 versions and each single post comes in 3 angles: the hook, the summary and the takeaway.

How it keeps to your post

A post that says something yours doesn't is a post you can't stand behind. So every post goes through 3 steps:

• It writes from your post only: every fact, number, name and quote comes from your post
• Code checks what it wrote: numbers and names that aren't in your post, words that sound like AI, and formatting that shows as symbols
• A second AI reads your post and the draft side by side, and rewrites only the sentences your post doesn't support

Still, read every post once before you publish it: it's your name on it.

Who is the Substack to social posts tool for?

It's for anyone who writes on Substack and wants more readers:

• Blog to social posts – bloggers on WordPress, Ghost or Medium, with the same writer
• LinkedIn post preview – writers checking how the feed cuts a post
• X character counter – anyone fitting a post into 280
• Threads character counter – anyone fitting a post into 500

Newsletter writers use it to fill a week of Notes and posts from each issue.

Write it with your own AI

Under the tool, the same instructions and your post go to Claude, ChatGPT, Grok, Perplexity or Gemini in one click, with your tone and extras.

It's the same writer and the same rules, free, and with no limit.