Aspect Ratio Calculator
Aspect ratio is the proportional relationship between width and height (W:H). Common ratios: 16:9 (widescreen, HD video, 1920×1080), 4:3 (classic TV, 1024×768), 1:1 (square, Instagram), 21:9 (ultrawide), 3:2 (DSLR photos). To calculate: divide both dimensions by their greatest common divisor (GCD). For 1920×1080: GCD=120, ratio=16:9. To scale: multiply both dimensions proportionally. Maintain aspect ratio when resizing to prevent distortion. Use in video editing, web design, photography cropping.
Calculate aspect ratios from dimensions or find dimensions from ratios. Includes presets for 16:9, 4:3, 21:9, 1:1, 9:16 and social media formats. Lock ratio to scale proportionally.
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What do you want to calculate?
Width (px)
Height (px)
Common Presets
Standard Ratios
Social Media
Common Aspect Ratios
| Ratio | Decimal | Common Use |
|---|---|---|
| 16:9 | 1.778 | HD Video, YouTube, TV |
| 4:3 | 1.333 | Classic TV, iPad |
| 21:9 | 2.333 | Ultrawide Monitors, Cinema |
| 1:1 | 1.000 | Instagram Square |
| 9:16 | 0.563 | TikTok, Stories, Shorts |
| 3:2 | 1.500 | 35mm Film, DSLR Photos |
| 2.39:1 | 2.390 | Anamorphic Widescreen |
Tip: Lock the ratio to scale dimensions proportionally. Press Enter to calculate, Escape to reset.
How to Use
- Enter your value in the input field
- Click the Calculate/Convert button
- Copy the result to your clipboard
Frequently Asked Questions
- What is aspect ratio?
- Aspect ratio is the proportional relationship between width and height, expressed as two numbers separated by a colon (e.g., 16:9, 4:3). A 16:9 aspect ratio means the width is 1.778 times the height. Aspect ratios are used for screens, videos, images, and design layouts to maintain consistent proportions when scaling.
- What is the most common aspect ratio?
- 16:9 is the most common aspect ratio, used by HDTVs, computer monitors, YouTube videos, and most modern displays. 16:9 became the standard around 2009, replacing the older 4:3 format. Other common ratios include 21:9 (ultrawide monitors), 1:1 (Instagram square posts), and 9:16 (vertical mobile video for TikTok, Instagram Stories).
- How do I calculate aspect ratio from dimensions?
- To calculate aspect ratio, divide both width and height by their greatest common divisor (GCD). For example, 1920×1080 pixels: GCD is 120, so 1920÷120 = 16 and 1080÷120 = 9, giving 16:9. Or calculate the ratio decimal (width÷height): 1920÷1080 = 1.778, which is 16:9.
- What aspect ratio should I use for social media?
- Instagram: 1:1 (square posts), 4:5 (portrait posts), 9:16 (stories/reels). YouTube: 16:9 (standard videos). TikTok: 9:16 (vertical). Facebook: 16:9 (landscape), 1:1 (square), 4:5 (vertical). Twitter: 16:9 (landscape), 1:1 (square). LinkedIn: 1:1 or 16:9. For maximum compatibility, create in the native aspect ratio of each platform.
- What happens if I use the wrong aspect ratio?
- Using the wrong aspect ratio causes letterboxing (black bars on sides) or pillarboxing (black bars top/bottom), cropping important content, or stretching/squashing that distorts the image. Social media platforms may auto-crop to fit their required ratios, potentially cutting off faces or key elements. Always preview how your content displays on target platforms before publishing.
- How do I maintain aspect ratio when resizing?
- To maintain aspect ratio, multiply both dimensions by the same scale factor. If you know one new dimension, calculate the other: New Height = (Original Height × New Width) ÷ Original Width. In image editors, hold Shift while dragging corners, or use the "constrain proportions" lock icon. This aspect ratio calculator can find missing dimensions instantly.
- What is the difference between 16:9 and 16:10?
- 16:9 (1.778:1) is wider and used for TVs, consumer monitors, and video content. 16:10 (1.6:1) is slightly taller, providing more vertical space for productivity tasks, and is common in professional monitors and laptops. At 1920 width, 16:9 = 1080px tall, while 16:10 = 1200px tall. Choose 16:9 for media consumption, 16:10 for work with documents and code.
- What aspect ratio is 4K?
- 4K (3840×2160 or 4096×2160) uses a 16:9 aspect ratio for consumer displays (Ultra HD) or ~1.9:1 (DCI 4K) for cinema. 4K refers to horizontal resolution (~4000 pixels), not aspect ratio. You can have 4K content in different aspect ratios — for example, ultrawide 4K at 21:9 (5120×2160) or vertical 4K at 9:16 (2160×3840).