π Aspect Ratio Calculator
Simplify any width and height into its smallest whole-number ratio, then work out the missing dimension when you resize.
1. Simplify a width Γ height
2. Scale to a new size
π Common aspect ratios
| Ratio | Decimal | Where you see it |
|---|---|---|
| 1:1 | 1.000 | Square β Instagram feed, avatars, album art |
| 5:4 | 1.250 | 8Γ10 photo prints, some older monitors |
| 4:3 | 1.333 | Standard-definition TV, iPad, most phone photos |
| 3:2 | 1.500 | 35 mm film, most DSLR and mirrorless cameras |
| 16:10 | 1.600 | WUXGA, MacBook displays, productivity monitors |
| 16:9 | 1.778 | HD / Full HD / 4K TV, YouTube, most video |
| 2:1 | 2.000 | Univisium, some cinematic crops |
| 21:9 | 2.333 | Ultrawide monitors, anamorphic cinema |
| 9:16 | 0.563 | Vertical video β Stories, Reels, TikTok, Shorts |
Frequently Asked Questions
What does an aspect ratio actually mean?
It is the proportional relationship between width and height, written as width : height. A 16:9 image is 16 units wide for every 9 units tall, so it stays the same shape whether it is 160 pixels or 3840 pixels wide. The ratio describes the shape, not the size β that is why the same ratio works for a phone screen and a cinema screen.
How do I find the missing dimension?
Multiply the known dimension by the ratio. If you know the width, height = width Γ (height part Γ· width part) β for 16:9 at 1920 px wide, the height is 1920 Γ 9 Γ· 16 = 1080 px. If you know the height instead, multiply by the inverse: width = height Γ (width part Γ· height part). This calculator does both directions automatically.
Does changing the aspect ratio crop or stretch the image?
It depends how you do it. Resizing a 4:3 photo to 16:9 by scaling stretches everything and squashes faces; changing the frame to 16:9 and cropping cuts off the top and bottom but keeps objects in proportion. Neither is "wrong" β use scaling when you control the source, and cropping when you must fit an existing photo into a fixed frame.
Which aspect ratio should I use for social media?
Think square-ish and vertical: 1:1 for Instagram and Facebook feed posts, 4:5 for Instagram portrait posts (it takes more vertical screen space), and 9:16 for Stories, Reels, TikTok and YouTube Shorts. For YouTube long-form and any traditional video, 16:9 remains the standard. Uploading at the platform's native ratio beats letting it crop for you.
π Recommended for You
As an Amazon Associate, Benditools earns from qualifying purchases.