Aspect Ratio Calculator
Find the aspect ratio of any photo, screen, or monitor — enter width and height or upload an image to instantly get 16:9, 9:16, 4:3, 1:1 and more.
Find aspect ratio from a photo
Drop an image or click to upload — we'll read its dimensions automatically
Or paste from clipboard: Ctrl+V
What is aspect ratio
Aspect ratio explained
Aspect ratio is the proportion between the width and height of an image, screen, or video. It is written as two numbers separated by a colon — for example, 16:9 for widescreen video or 1:1 for a square Instagram post. The ratio is independent of resolution: 1280×720, 1920×1080, and 3840×2160 all have the same 16:9 aspect ratio.
How the calculator works
Type the width and height in pixels — the calculator instantly computes the ratio, reduces it to its simplest form (for example, 1920×1080 → 16:9), and shows you the closest common standard. If you do not need exact dimensions, just click a preset like 16:9, 9:16, or 4:3, and the fields will be filled in for you.
Find aspect ratio from a photo
Do not know your image dimensions? Drop a file into the calculator or paste it from the clipboard with Ctrl+V — the tool reads width and height directly from the file and shows the aspect ratio immediately. The file never leaves your browser, so your photos stay private.
Why use this calculator
No upload to a server
Images are processed entirely in your browser. Your photos are never sent anywhere and stay completely private.
Paste with Ctrl+V
Copy an image from any application and paste it with a keyboard shortcut — the calculator reads the dimensions and ratio automatically.
Quick presets
16:9 for YouTube, 9:16 for Reels and Stories, 1:1 for Instagram, 4:3 for classic photography — choose with one click.
Exact and standard
The calculator shows both the exact reduced fraction and the closest standard ratio, so you can see how close your dimensions are to 16:9 or 4:3.
How to find aspect ratio of a photo or screen
Three ways — type the numbers, pick a preset, or upload the image itself.
Enter dimensions or upload a photo
Type the width and height in pixels, drop an image into the upload zone, or paste it from the clipboard with Ctrl+V.
Get the aspect ratio
The calculator displays the reduced fraction (for example, 16:9), the decimal ratio (1.778:1), and the orientation — landscape, portrait, or square.
Compare with standards
If your image is close to a standard ratio, the calculator highlights the matching preset — 16:9, 4:3, 3:2, and more.
Aspect ratio and screen resolution
Most common screen resolutions and their aspect ratios. All Full HD, Quad HD and 4K resolutions share the same 16:9 ratio.
| Resolution | Aspect ratio | Name |
|---|---|---|
| 1280×720 | 16:9 | HD (720p) |
| 1920×1080 | 16:9 | Full HD (1080p) |
| 2560×1440 | 16:9 | QHD (2K) |
| 3840×2160 | 16:9 | 4K UHD |
| 1366×768 | 16:9 | HD laptop |
| 1440×900 | 16:10 | WXGA+ |
| 1680×1050 | 16:10 | WSXGA+ |
| 2560×1080 | 21:9 | UltraWide FHD |
| 3440×1440 | 21:9 | UltraWide QHD |
| 1024×768 | 4:3 | XGA |
| 1080×1080 | 1:1 | Instagram square |
| 1080×1920 | 9:16 | Stories / Reels / Shorts |
| 1080×1350 | 4:5 | Instagram portrait |
Frequently asked questions
How do I find the aspect ratio of a photo online?
Upload a photo to the calculator or paste it with Ctrl+V — the ratio appears instantly. You can also enter width and height manually, and the calculator will reduce them to a standard fraction like 16:9 or 4:3.
What does 16:9 aspect ratio mean?
16:9 is the widescreen format. The width is 1.778 times larger than the height. It is used for HD and 4K video, monitors, TVs, and YouTube. Resolutions 1280×720, 1920×1080 (Full HD), 2560×1440 (2K), and 3840×2160 (4K) all share this ratio.
What is the difference between 16:9 and 9:16?
16:9 is horizontal (landscape) for video and monitors. 9:16 is the same ratio rotated vertically — used for smartphones, Stories, Reels, TikTok, and YouTube Shorts. In short, 9:16 is 16:9 turned on its side.
What aspect ratio do Instagram, TikTok, and YouTube use?
Instagram: 1:1 for square feed posts, 4:5 for portrait posts, 9:16 for Stories and Reels. TikTok: 9:16 only (vertical video). YouTube: 16:9 for main videos, 9:16 for Shorts. Reels on every platform use 9:16.
How does aspect ratio relate to resolution?
Resolution is the actual pixel dimensions (such as 1920×1080), while aspect ratio is the proportion between them (16:9). One ratio can have many resolutions: 1280×720, 1920×1080, and 3840×2160 are all 16:9 but with different levels of detail.
How do I change the aspect ratio of a photo?
You can change the ratio by cropping or resizing. Convertilo has dedicated tools for this: "Crop image" cuts the photo to a specific ratio without distortion, while "Resize image" stretches it to a specific resolution.
What aspect ratio does an iPhone photo use?
A standard iPhone photo has a 4:3 aspect ratio (for example, 4032×3024). If you set the camera to 16:9 mode, the photo becomes 16:9 (4032×2268). iPhone videos are recorded in 16:9 by default.
How do I find the aspect ratio of my monitor?
Open your display settings to see the monitor resolution (usually 1920×1080 or 2560×1440). Enter those numbers in the calculator — the ratio appears instantly. Most modern monitors are 16:9, ultra-wides are 21:9, and older square monitors are 4:3 or 5:4.