Substack image sizes
Substack uses separate assets for its email banner, square publication logo, horizontal wordmark, square cover image and social preview. The current recommendations are 1100×220, at least 256×256, at least 1344×256, at least 600×600 and at least 1200×630 pixels respectively.
One source conflict is preserved rather than hidden: Substack lists 1200×630 for social previews and calls the ratio 14:10 in the same bullet, even though those numbers do not match. The detail page follows the explicit pixels and explains the discrepancy.
Quick reference
| Format | Dimensions | Ratio | Max size |
|---|---|---|---|
| Email Banner | 1100 × 220 px | 5:1 | — |
| Publication Logo | 256 × 256 px | 1:1 | — |
| Publication Wordmark | 1344 × 256 px | 5.25:1 | — |
| Publication Cover Image | 600 × 600 px | 1:1 | — |
| Social Preview Image | 1200 × 630 px | 1.91:1 | — |
Publication Logo256×256px
Substack says a publication logo should be at least 256×256 pixels. Its image-dimensions guide recommends a transparent background, which keeps a square logo flexible across the publication header and related surfaces.
Substack distinguishes the compact square publication logo from the much wider wordmark. The logo should be at least 256×256 pixels.
Dimensions
256 × 256 px
Aspect ratio
1:1
Formats
PNG
Best practices
- •Use a square source at least 256×256 pixels.
- •Export with transparency when the mark should sit on different backgrounds.
- •Move a long publication name into the separate wordmark rather than shrinking it inside the logo.
Publication Wordmark1344×256px
Substack says a publication wordmark should be a horizontal image at least 1344×256 pixels. The website editor can resize its displayed appearance without changing the recommended source dimensions.
The wordmark carries a publication name in a wide header-friendly shape. Substack's current theme guide sets the source minimum at 1344×256 pixels.
Dimensions
1344 × 256 px
Aspect ratio
5.25:1
Best practices
- •Use a horizontal image at least 1344×256 pixels.
- •Keep the publication name large enough to remain readable when the header is resized.
- •Design the wordmark and square logo as separate assets instead of forcing one crop to do both jobs.
Publication Cover Image600×600px
Substack recommends a publication cover image at least 600×600 pixels. A square source keeps the cover usable in compact publication and discovery surfaces without depending on a wide crop.
The publication cover image is separate from the email banner, logo and social preview. Substack's image guide sets a minimum square source of 600×600 pixels.
Dimensions
600 × 600 px
Aspect ratio
1:1
Best practices
- •Use a square image at least 600×600 pixels.
- •Keep the focal point and any title treatment legible at thumbnail size.
- •Create a separate square composition instead of center-cropping the email banner.
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What are the main Substack image sizes?
Email banner: 1100×220; logo: at least 256×256; wordmark: at least 1344×256; cover image: at least 600×600; social preview: at least 1200×630 pixels.
Does Substack publish conflicting preview guidance?
Yes. Its current help page pairs 1200×630 pixels with a 14:10 ratio, although those shapes differ. This guide uses the explicit pixel dimensions and flags the conflict.
Other platform guides
Sources
Guide last verified: August 28, 2026. This hub summarizes 5 formats and cites 3 sources across this page and the linked format pages.
← All sizes
Social Preview Image1200×630px
Substack recommends social and post preview images at least 1200×630 pixels. The same official bullet also says preview images use a 14:10 ratio, which does not match 1200×630, so this page uses the explicit pixel dimensions and records the conflict rather than silently reconciling it.
The social or post preview image is the thumbnail used when a Substack post is represented outside the full article. Substack's current image guide gives an explicit minimum of 1200×630 pixels.
Dimensions
1200 × 630 px
Aspect ratio
1.91:1
Best practices