Checked against the source
Threads Carousel Image Size: 20 Items, 8 MB, 320 to 1440 px
Short answer
Meta's Threads API allows a carousel of 2 to 20 images, videos or a mix. Images are JPEG or PNG, 8 MB at most, with a width of 320 to 1440 px and an aspect ratio limit of 10:1. We suggest 1080 × 1350 px at 4:5.
Key takeaways
- A carousel needs at least two items and holds at most twenty. Items can be images, videos or a mix.
- Image rules: JPEG or PNG, 8 MB maximum, aspect ratio limit 10:1, width from 320 to 1440 px. Narrower images are scaled up to 320 and wider ones scaled down to 1440.
- Threads converts other color spaces to sRGB, so export in sRGB to avoid a color shift.
- A carousel counts as a single post against a profile's rate limit, according to the API documentation.
- These are the publishing API limits. The Threads app may apply limits of its own when you post by hand.
The size
| What | Value |
|---|---|
| Width | 1080 px |
| Height | 1350 px |
| Aspect ratio | 4:5 |
What the platform publishes
| What | Published value |
|---|---|
| Carousel length | 2 to 20 images, videos, or a mix |
| Image formats | JPEG and PNG |
| Image file size | 8 MB maximum |
| Aspect ratio limit | 10:1 |
| Width | Minimum 320 px (scaled up if smaller), maximum 1440 px (scaled down if larger) |
| Color space | sRGB; other color spaces are converted to sRGB |
| Rate limit | A carousel counts as a single post against the profile rate limit |
| Koldflux recommendation | 1080 × 1350 px (4:5, inside the 320 to 1440 px width band) |
These limits come from the Threads publishing API documentation. The Threads app may apply its own limits when you post by hand.
Source: Meta for Developers: Threads API, posts (checked 2026-10-09)
What your photo loses
| Source | Scale to fill | Lost each side | Lost top and bottom | Source area kept |
|---|---|---|---|---|
| Phone photo, 16:9 (4032 x 2268) | 0.595 (max(1080 / 4032, 1350 / 2268)) | 660 px ((2400 - 1080) / 2) | none ((1350 - 1350) / 2) | 15.9% |
| Camera, 3:2 (6000 x 4000) | 0.338 (max(1080 / 6000, 1350 / 4000)) | 472.5 px ((2025 - 1080) / 2) | none ((1350 - 1350) / 2) | 6.1% |
| Square export (1080 x 1080) | 1.25 (max(1080 / 1080, 1350 / 1080)) | 135 px ((1350 - 1080) / 2) | none ((1350 - 1350) / 2) | 125% |
What this frame costs to upload
| Format | File size | Against PNG |
|---|---|---|
| PNG, lossless | 1,549,502 bytes (1513 kB) | the reference |
| JPEG, `-q:v 5` | 190,524 bytes (186 kB) | 12% of the PNG |
| WebP, `-q:v 75` | 71,070 bytes (69 kB) | 5% of the PNG |
| Threads maximum image size, if that is the cap | 8,388,608 bytes (8192 kB) | the PNG is 18% of it |
ffmpeg 6.1.1. Upper bounds: a flat logo or a soft portrait compresses much further. The full method is in the evidence file.
Resize it now
Scales and center-crops any image to exactly 1080 x 1350 px, in your browser. Nothing is uploaded, there is no file size cap and no daily limit.
Batch is unlimited and free - every image is processed on your device, so there is no queue and no daily cap.
What the API documentation says
The Threads API posts page says you can publish up to 20 images, videos, or a mix of the two in a carousel post, that carousels require a minimum of two children, and that a carousel counts as a single post against a profile's rate limit. Its media specification section lists the image rules.
| What | Published value |
|---|---|
| Carousel length | 2 to 20 items |
| Formats | JPEG and PNG |
| File size | 8 MB maximum |
| Aspect ratio limit | 10:1 |
| Minimum width | 320 px (scaled up if necessary) |
| Maximum width | 1440 px (scaled down if necessary) |
| Height | Varies with width and aspect ratio |
| Color space | sRGB; other color spaces are converted to sRGB |
What gets scaled, computed at 4:5
Because the API scales width into the 320 to 1440 px band, the result for a given upload is predictable. Take a 4:5 image, the shape we use. A 300 × 375 px upload is below the floor, so it is scaled up to 320 × 400 px. A 1080 × 1350 px upload is inside the band and is left alone. A 2000 × 2500 px upload is above the ceiling, so it is scaled down to 1440 × 1800 px (2000 × 0.72 = 1440).
| Upload | What the API does | Result |
|---|---|---|
| 300 × 375 px | Scaled up to the 320 px minimum | 320 × 400 px |
| 1080 × 1350 px | Inside the band, unchanged | 1080 × 1350 px |
| 2000 × 2500 px | Scaled down to the 1440 px maximum | 1440 × 1800 px |
The scaling is the only thing the documentation promises. It does not say how the image is displayed in the feed, so do not rely on a fixed crop.
The 10:1 ratio limit
An aspect ratio limit of 10:1 is very permissive. At the 1440 px maximum width, a 10:1 landscape image is 144 px tall, so nothing flatter than that fits the limit. Normal photos at 4:5, 1:1 or 16:9 are nowhere near it.
Mixing video into a carousel
A carousel can hold video as well as images. The same page lists the video rules: MOV or MP4, HEVC or H264, 23 to 60 FPS, up to 1920 horizontal pixels, up to 5 minutes and 1 GB. If your carousel mixes both, check each file against its own list.
Free tools:Threads post image sizeThreads profile picture size
Frequently asked questions
How many images can a Threads carousel have?
Two to twenty items, images, videos or a mix, according to Meta's Threads API documentation.
What image size does Threads accept?
JPEG or PNG, up to 8 MB, a width from 320 to 1440 px and an aspect ratio up to 10:1.
What happens if my image is wider than 1440 px?
The documentation says it will be scaled down to 1440 px wide, and scaled up if narrower than 320 px.
Does a Threads carousel count as many posts?
No. The API documentation says a carousel counts as a single post against a profile's rate limit.
Do these limits apply when I post in the app?
They come from the publishing API documentation. The app may have its own limits.
Other Threads sizes
Sources
- Meta for Developers: Threads API, posts (checked 2026-10-09)