Aspect Ratio in Pixels: 9:16, 16:9, 4:3 and More [2026]
What is 9:16 in pixels? What about 16:9, 4:3, or 4:5? This guide gives you the exact numbers for every common ratio, explains per-platform sizes, and shows how to calculate any ratio from width and height.
Table of Contents
Quick Reference
- 9:16 in pixels: 1080 x 1920 (standard), 720 x 1280 (HD), 1440 x 2560 (2K)
- 16:9 in pixels: 1920 x 1080 (1080p), 1280 x 720 (720p), 3840 x 2160 (4K)
- 4:3 in pixels: 1024 x 768 (XGA), 1920 x 1440, 2048 x 1536 (iPad retina)
- 1:1 in pixels: 1080 x 1080 (Instagram square), 720 x 720, 3000 x 3000
- 4:5 in pixels: 1080 x 1350 (Instagram portrait feed)
What an aspect ratio actually means
An aspect ratio is the relationship between the width and height of an image or screen, expressed as two numbers separated by a colon. The ratio 16:9 means the image is 16 units wide for every 9 units tall. It says nothing about how many pixels the image contains — only the proportions.
Two images can have the same aspect ratio and very different resolutions. A 1280x720 image and a 3840x2160 image are both 16:9, but one has four times as many pixels. The ratio tells you the shape; the resolution tells you the size.
To convert a ratio to pixel dimensions, you choose a base size. For 9:16 and a width of 1080:
- Height = 1080 x (16/9) = 1920
- Result: 1080 x 1920 px
The Aspect Ratio Calculator does this automatically for any ratio and any base dimension.
Every ratio in pixels: full reference table
The table below lists every common aspect ratio with its standard pixel sizes, the decimal equivalent, and the main use cases.
| Ratio | Common pixel sizes | Decimal | Best for |
|---|---|---|---|
| 9:16 | 720x1280, 1080x1920, 1440x2560 | 0.5625 | Reels, TikTok, YouTube Shorts, Stories |
| 16:9 | 1280x720, 1920x1080, 3840x2160 | 1.778 | YouTube, HD displays, presentations |
| 1:1 | 720x720, 1080x1080, 3000x3000 | 1.000 | Instagram square, profile photos, album art |
| 4:5 | 864x1080, 1080x1350, 1440x1800 | 0.800 | Instagram portrait feed (tallest allowed) |
| 3:4 | 768x1024, 1200x1600, 1536x2048 | 0.750 | Mobile portrait, e-commerce products |
| 4:3 | 1024x768, 1920x1440, 2048x1536 | 1.333 | iPad, classic cameras, older screens |
| 3:2 | 1800x1200, 2400x1600, 6000x4000 | 1.500 | DSLR cameras, 4x6 prints |
| 2:3 | 800x1200, 1000x1500, 1200x1800 | 0.667 | Pinterest pins, portrait prints |
| 5:4 | 1280x1024, 2500x2000, 3000x2400 | 1.250 | 8x10 photo prints, framed portraits |
| 21:9 | 2560x1080, 3440x1440, 5120x2160 | 2.333 | Ultrawide monitors, cinematic banners |
| 2:1 | 1200x600, 2000x1000, 2400x1200 | 2.000 | Twitter/X cards, web banners |
9:16 in pixels
9:16 is the dominant vertical format for social media video and stories. The ratio means the height is 16/9 times the width. At a width of 1080 px, height = 1080 x (16/9) = 1920 px.
The three standard 9:16 sizes are:
- 720 x 1280 px (HD): minimum recommended for TikTok and YouTube Shorts
- 1080 x 1920 px (Full HD): the universal standard for Instagram Reels, Stories, TikTok, and Snapchat
- 1440 x 2560 px (2K): premium quality; larger than most platforms encode at
For any platform, export at 1080 x 1920 px unless you have a specific reason to go higher. The platforms transcode to lower resolutions anyway. Keep text and faces away from the top and bottom 10% of the frame, where UI overlays appear.
Use the crop to 9:16 tool to trim any image to this ratio, then export at 1080x1920.
16:9 in pixels
16:9 is the standard widescreen format for YouTube, HD and 4K television, desktop monitors, and presentation slides. The ratio means the width is 16/9 times the height.
The three standard 16:9 sizes are:
- 1280 x 720 px (720p HD): the minimum for YouTube HD streaming
- 1920 x 1080 px (1080p Full HD): the most common video resolution
- 3840 x 2160 px (4K UHD): used for 4K YouTube uploads and professional production
For YouTube thumbnails, the recommended size is 1280 x 720 px at 16:9, with a minimum width of 640 px and a file size under 2 MB.
Use the crop to 16:9 tool to trim a portrait photo to the widescreen format.
4:3 in pixels
4:3 is the classic display ratio used by older monitors, iPads, standard-definition television, Micro Four Thirds cameras, and many phone cameras in their default capture mode. The width is 4/3 times the height.
Common 4:3 pixel sizes:
- 640 x 480 px (VGA): legacy web and video standard
- 1024 x 768 px (XGA): older laptop and monitor standard
- 1920 x 1440 px: high-resolution 4:3, used for some digital cameras
- 2048 x 1536 px: iPad Retina display resolution (older models)
For iPad wallpapers, crop to 4:3 and export at 2048 x 1536 px for the sharpest result. Use the crop to 4:3 tool to trim any image to this format.
Per-platform size guide
Each platform has specific recommended sizes. Using the exact recommended size prevents the platform from compressing or cropping your image. Here are the definitive sizes for 2026:
- Reels and Stories: 9:16, 1080 x 1920 px. This is full-screen portrait video.
- Portrait feed post: 4:5, 1080 x 1350 px. The tallest ratio Instagram allows in the feed. Takes up more scroll space than square.
- Square feed post: 1:1, 1080 x 1080 px. Still supported and clean.
- Landscape feed post: 1.91:1, 1080 x 566 px. Maximum width post.
TikTok
- Video (standard): 9:16, 1080 x 1920 px at 60 fps for best quality.
- Thumbnail: 9:16, 1080 x 1920 px or any 9:16 crop.
- Photo mode: 9:16 recommended; square 1:1 also accepted.
YouTube
- Video: 16:9, 1920 x 1080 px (1080p) or 3840 x 2160 px (4K).
- Thumbnail: 16:9, 1280 x 720 px minimum, under 2 MB.
- Shorts: 9:16, 1080 x 1920 px.
- Channel art / banner: 2560 x 1440 px (safe zone 1546 x 423 px center).
- Standard pin: 2:3, 1000 x 1500 px. Anything taller is truncated.
- Square pin: 1:1, 1000 x 1000 px.
- Story pin: 9:16, 1080 x 1920 px.
Twitter / X
- In-stream photo: 2:1, 1200 x 600 px. Shown at this ratio in the feed.
- Profile photo: 400 x 400 px minimum.
- Header: 1500 x 500 px (3:1 ratio).
How to calculate ratio from dimensions
To find the aspect ratio of any pair of pixel dimensions, divide both by their greatest common divisor (GCD). The GCD is the largest number that divides both values without a remainder.
Example: what ratio is 1920 x 1080?
- Find GCD(1920, 1080). The GCD is 120.
- Divide: 1920 / 120 = 16, 1080 / 120 = 9.
- Result: 16:9.
Example: what ratio is 1080 x 1920?
- GCD(1080, 1920) = 120.
- Divide: 1080 / 120 = 9, 1920 / 120 = 16.
- Result: 9:16.
Example: what ratio is 1200 x 628?
- GCD(1200, 628) = 4.
- Divide: 1200 / 4 = 300, 628 / 4 = 157.
- Result: 300:157 (not a standard ratio; this is a non-standard Open Graph image size).
When the simplified ratio does not match a standard name, the image is a non-standard proportion. The Pixels to ratio tab in the calculator handles this automatically, showing you both the simplified form and whether it matches a standard name.
Cropping and resizing to a ratio
Knowing the pixel dimensions is only the first step. To actually change your image to the correct ratio:
- Crop (change the shape): Use the SammaPix crop tools. Each ratio has its own page with a live crop box locked to that ratio. The crop removes pixels outside the selection without changing the remaining pixel quality.
- Resize (change the total pixel count): After cropping, use the image resizer to scale the cropped image to the exact pixel dimensions you need (e.g. 1080 x 1920 px for a 9:16 Reel).
The crop tools available for each standard ratio:
- Crop to 9:16 (Reels, Stories, TikTok, Shorts)
- Crop to 16:9 (YouTube, presentations)
- Crop to 1:1 (Instagram square, profile photos)
- Crop to 4:5 (Instagram portrait feed)
- Crop to 3:4 (mobile portrait, products)
- Crop to 4:3 (iPad, classic cameras)
- Crop to 3:2 (DSLR, 4x6 prints)
- Crop to 2:3 (Pinterest, portrait prints)
- Crop to 5:4 (8x10 prints)
- Crop to 21:9 (ultrawide, banners)
FAQ
What is 9:16 in pixels?
9:16 in pixels depends on the base size you choose. The most common sizes are: 720x1280 (HD), 1080x1920 (Full HD, the standard for Reels and TikTok), and 1440x2560 (2K). The rule is: height = width times (16/9), so a width of 1080 gives 1080 x (16/9) = 1920.
What is 16:9 in pixels?
16:9 in pixels: 1280x720 (HD), 1920x1080 (Full HD / 1080p), 2560x1440 (2K / QHD), and 3840x2160 (4K UHD). The rule is: height = width divided by (16/9). For 1920: 1920 / 1.778 = 1080.
What is 4:3 in pixels?
4:3 in pixels: 800x600, 1024x768, 1280x960, 1920x1440, 2048x1536. Width divided by height always equals 1.333. This ratio is standard for iPads, older monitors, and many phone cameras in their native capture mode.
How do I calculate an aspect ratio from any width and height?
Divide both numbers by their greatest common divisor (GCD). Example: 1920 and 1080 have a GCD of 120. 1920/120 = 16 and 1080/120 = 9, so the ratio is 16:9. Use the SammaPix Aspect Ratio Calculator to do this automatically.
What ratio is 1080x1920?
1080x1920 is a 9:16 image. This is the standard portrait resolution for Instagram Reels and Stories, TikTok, YouTube Shorts, and Snapchat. Width 1080 divided by GCD 120 = 9, height 1920 divided by 120 = 16.
