About This Calculator
This aspect ratio calculator lets you compute the proportional relationship between width and height. You can either enter a pair of dimensions to determine the ratio, or scale a new width or height from a fixed ratio like 16:9, 4:3, or any custom values.
Aspect ratios are widely used in video production, screen resolutions, printing layouts, web design, and more. The result is unitless and applies equally whether you use pixels, inches, or centimeters—as long as both inputs use the same unit.
How It Works
- Select a mode: calculate a ratio from dimensions, or scale a width or height based on a preset or custom ratio.
- When calculating from dimensions, the calculator reduces the ratio to its simplest form and also shows the decimal equivalent.
- When scaling, the tool lets you enter either a width or a height, and instantly calculates the other to maintain the chosen ratio.
- Supports any consistent unit: px, in, cm, mm, etc.
Common Resolutions by Aspect Ratio
16:9 (Widescreen HD)
| Resolution | Use Case |
|---|---|
| 3840×2160 | 4K UHD |
| 2560×1440 | QHD / 2K |
| 1920×1080 | Full HD |
| 1600×900 | HD+ |
| 1280×720 | HD / 720p |
| 854×480 | SD widescreen |
4:3 (Standard / Legacy)
| Resolution | Use Case |
|---|---|
| 1600×1200 | UXGA monitors |
| 1024×768 | XGA monitors |
| 800×600 | SVGA projectors |
| 640×480 | VGA standard |
3:2 (Photography & Devices)
| Resolution | Use Case |
|---|---|
| 3000×2000 | Microsoft Surface |
| 1500×1000 | DSLR photography |
| 900×600 | Web images |
1:1 (Square Format)
| Resolution | Use Case |
|---|---|
| 1080×1080 | Instagram posts |
| 1000×1000 | Print thumbnails |
| 600×600 | Low-res square thumbnails |
9:16 (Vertical / Portrait)
| Resolution | Use Case |
|---|---|
| 1080×1920 | Vertical video (TikTok, Reels) |
| 720×1280 | HD vertical |
| 480×854 | Vertical SD |
Frequently Asked Questions
What is an aspect ratio?
It’s the proportional relationship between width and height, usually written as W:H (e.g. 4:3 or 16:9).
Is this tool only for images?
No. It's designed for general use—videos, screens, print layouts, slide design, and any scenario where consistent proportions matter.
Can I use any unit?
Yes. You can use any unit (pixels, inches, cm, etc.) as long as both width and height use the same one. The ratio result itself is unitless.
What if I only know one side?
In “scale from ratio” mode, you can enter either width or height and the calculator will compute the other value based on your selected ratio.
Why are aspect ratios important?
They help ensure content scales correctly across devices, maintains framing in media, and avoids distortion in prints or videos.