How to Calculate Aspect Ratio Dimensions
Click a preset button for your target platform — 16:9 for YouTube videos, 9:16 for TikTok or Instagram Reels, 1:1 for Instagram Feed posts, 4:5 for Instagram Portrait, 3:2 for DSLR photos, 21:9 for ultrawide monitors, or 2:1 for Twitter/X header banners. Clicking a preset sets the ratio and recalculates dimensions based on your current Width or Height value. For non-standard ratios, type your values directly into the Custom Ratio fields.
To find the height for a given width, type your desired width in pixels into the Width field — Height updates automatically. To work in the opposite direction, type into the Height field and Width will update. Use the Scale buttons to quickly find related sizes: ÷2 halves both dimensions (useful for thumbnail exports), ×2 doubles them (for @2x retina assets), ÷4 gives a quarter-size preview, and ×4 gives a 4K version. The Simplified Ratio display always shows the lowest-integer form of the ratio so you can verify the math at a glance.
Why Use This Aspect Ratio Calculator?
Getting dimensions right the first time prevents wasted re-exports and rejected uploads across every major platform.
- Social media presets eliminate the need to memorize platform-specific dimensions — 8 platforms covered in one click
- Bidirectional calculation — change width to find height, or change height to find width
- Scale buttons (÷4, ÷2, ×2, ×4) keep dimensions as whole integers, avoiding fractional pixel artifacts
- Simplified ratio display confirms you're using the correct ratio before export
- Visual aspect ratio preview lets you sanity-check portrait vs. landscape orientation
- Works for video, photo, banner, canvas, and print dimensions equally
Frequently Asked Questions
What are the standard video dimensions for major platforms in 2026?
YouTube: 1920×1080 (16:9) for HD, 3840×2160 (16:9) for 4K. TikTok and Instagram Reels: 1080×1920 (9:16). Instagram Feed: 1080×1080 (1:1) for square posts, 1080×1350 (4:5) for portrait posts. Twitter/X: 1200×675 (16:9) for in-stream photos, 1500×500 (3:1) for header banners. Facebook: 1200×630 for link thumbnails. LinkedIn: 1200×627 for shared images. These are standard recommendations as of early 2026; always check the platform's help center before final export for important campaigns.
What is the difference between 16:9 and 1920×1080?
16:9 is an aspect ratio describing the proportional shape of the frame without specifying actual pixel counts. 1920×1080 is a specific resolution that happens to have a 16:9 ratio (1920 ÷ 1080 = 16/9). Many other resolutions also have a 16:9 ratio: 1280×720 (720p), 2560×1440 (1440p), 3840×2160 (4K), and 7680×4320 (8K). This calculator works with any width or height — enter your desired dimension and get the matching value for whatever ratio you need.
Why should I scale video dimensions by powers of 2?
Scaling by powers of 2 (÷2, ÷4, ×2, ×4) keeps both dimensions as whole integers, preventing fractional pixels that cause anti-aliasing artifacts. Many video encoders (including H.264 and H.265) require dimensions divisible by 2 or 16, and odd-numbered dimensions can cause encoding errors or subtle blurriness. Using ÷2 also produces the correct sizes for retina display assets: a 320×180 thumbnail needs a 640×360 @2x version — both obtained cleanly by dividing and multiplying by 2.
How do I calculate the aspect ratio from a given width and height?
To find the aspect ratio of an image or video, divide both the width and height by their greatest common divisor (GCD). For example, 1920×1080: the GCD of 1920 and 1080 is 120, so 1920÷120 = 16 and 1080÷120 = 9, giving an aspect ratio of 16:9. Similarly, 1080×1350 has a GCD of 270, producing 4:5. This calculator does this automatically — enter any width and height, and the Simplified Ratio display instantly shows the reduced fraction. This is useful for identifying the ratio of existing images before resizing them for a different platform. To resize and compress images once you know the target dimensions, use our <a href="/tools/image-resizer-compressor/">Image Resizer & Compressor</a>. For choosing harmonious colors for your resized assets, the <a href="/tools/color-palette-generator/">Color Palette Generator</a> creates accessible color schemes.
What aspect ratio should I use for social media stories and reels?
Instagram Stories, Instagram Reels, TikTok, YouTube Shorts, Facebook Stories, and Snapchat all use a 9:16 aspect ratio (vertical, portrait orientation). The recommended resolution is 1080×1920 pixels, which provides sharp quality on modern smartphone screens. For Instagram Feed posts, 1:1 (1080×1080) is the classic square format, while 4:5 (1080×1350) is the tallest portrait crop the feed allows and occupies more screen real estate, which can improve engagement. For YouTube standard videos and most web embeds, 16:9 (1920×1080 for Full HD or 3840×2160 for 4K) remains the universal standard. Always check the latest platform guidelines before publishing, as recommended sizes can change with app updates.
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