Substack · free & no signup
Substack Header Size: 1344 × 256
The wordmark across the top of your publication, at the size Substack actually asks for.
Drag the image to reposition it · scroll or pinch to zoom
Batch mode
Every image will be resized to and downloaded as one ZIP. Change the size below before you start.
Works with images up to roughly 50 MP (about 8000 × 6000 px) depending on your device's memory. WebP export is unavailable in a few older Safari versions — the option is disabled automatically when that is the case.
How it works
Three steps, no account, no watermark.
Add your image
Drag a file onto the box, click to browse, or paste straight from your clipboard with Ctrl + V. Nothing is uploaded anywhere.
Frame it
The crop box is already locked to 1344 × 256. Drag the image to move it and scroll or pinch to zoom until it looks right.
Download
Pick PNG, JPG or WebP. The file is compressed automatically to stay under Substack's limit — or grab every Substack size at once as a ZIP.
About the substack header size
Substack's own documentation asks for a publication wordmark of at least 1344 × 256 pixels. That image appears at the top of your Substack website and on your profile, and it is the first branded thing a reader sees when they land from a shared link. It is a wide, short strip, which means it suits a logotype or your publication's name set as type far better than it suits a photograph.
Substack sites render in both light and dark themes, and readers choose. A wordmark baked onto a white rectangle looks fine in one and like a glaring patch in the other. A transparent PNG solves it in one step. Substack asks for transparency on the logo for the same reason, and it is worth doing here even though the header will technically accept a flat JPG.
Every Substack image size
The complete list — click any row to load that size into the tool, or use the ZIP button to export all of them at once. Official means the platform publishes that figure itself; Recommended means it is the widely used standard where the platform publishes none.
| Image | Size (px) | Max file | Source | What to know | Action |
|---|---|---|---|---|---|
| Publication header | 1344 × 256 | 4 MB | Official | Substack asks for at least 1344 × 256. A transparent PNG adapts to both themes. | |
| Publication logo | 256 × 256 | 4 MB | Official | At least 256 × 256 with a transparent background. | |
| Email banner | 1100 × 220 | 4 MB | Official | Sits at the top of every email you send. Can be taller if you want. | |
| Social preview image | 1200 × 630 | 4 MB | Official | What people see when your post is shared as a link. |
Tips for Substack
What actually makes the difference once the size is right.
Use a transparent PNG
Substack renders in light and dark themes. A wordmark on a solid white background looks broken for every reader using dark mode.
Type, not photography
At 1344 × 256 the strip is over five times wider than it is tall. Photographs get cropped to a sliver; a logotype fits naturally.
Leave breathing room inside the image
Do not run your type to the very edge of the canvas. A little padding inside the file keeps the header from feeling cramped against the page.
Match it to the logo and social preview
The 256 × 256 logo and the 1200 × 630 social preview appear alongside it in feeds and inboxes. One palette across all three makes a new publication look established.
Frequently asked questions
What size is a Substack header?
At least 1344 × 256 pixels for the publication wordmark, according to Substack's own documentation. It appears at the top of your site and on your profile.
What size is the Substack logo?
At least 256 × 256 pixels with a transparent background. It is separate from the header wordmark and is in the table on this page.
What size is the Substack email banner?
Substack recommends 1100 × 220 pixels, and notes it can be taller if your design needs it. It is included in the ZIP pack here.
Should the header be transparent?
Yes, use a PNG with transparency. Substack renders in both light and dark themes, and a solid background will clash with one of them.
What size is the social preview image?
1200 × 630 pixels — what readers see when your post is shared as a link. It is in the table below.
Is anything uploaded to a server?
No. Every resize happens in your own browser.
More size tools
Same tool, every other platform — all free and all local to your browser.