Calculate image and video dimensions for any aspect ratio. Presets for YouTube, Instagram, TikTok, and all major platforms. Find ratio from pixel dimensions.
📐 Open Aspect Ratio CalculatorFree · No signup · Social media presets · Visual preview
An aspect ratio is the proportional relationship between the width and height of a rectangle — a screen, image, video, or any visual element. It is expressed as two numbers separated by a colon: 16:9 means the width is 16 units for every 9 units of height. The ratio describes shape without specifying size — a 1280×720 and a 3840×2160 screen are both 16:9.
Aspect ratios matter when sizing images for different platforms, resizing video for different screens, planning camera shots, or designing print layouts. Getting the ratio wrong results in stretched images, cropped content, or black bars around video.
Calculate missing dimension from ratio + one known dimension
Lock width or height while the other updates automatically
Find simplified ratio from any pixel dimensions (GCD method)
Visual rectangle preview that updates in real-time
10 preset ratios: 16:9, 4:3, 1:1, 9:16, 21:9, 3:2, 2:3, 5:4, 32:9, 4:5
Custom ratio input (any W:H)
10 social media presets: YouTube, TikTok, Instagram, LinkedIn, and more
Common screen resolution reference table
| Platform | Format | Dimensions | Ratio |
|---|---|---|---|
| YouTube | Video Thumbnail | 1280 × 720 | 16:9 |
| YouTube | Shorts | 1080 × 1920 | 9:16 |
| Feed Square | 1080 × 1080 | 1:1 | |
| Feed Portrait (best) | 1080 × 1350 | 4:5 | |
| Story / Reels | 1080 × 1920 | 9:16 | |
| TikTok | Video | 1080 × 1920 | 9:16 |
| Cover Photo | 820 × 312 | ~2.63:1 | |
| Twitter/X | Header | 1500 × 500 | 3:1 |
| Banner | 1584 × 396 | 4:1 | |
| Pin | 1000 × 1500 | 2:3 |
The widescreen standard. Used by YouTube, most desktop monitors, TVs, and the majority of modern cameras. The "HD" ratio.
Common uses: YouTube, Vimeo, Netflix, desktop wallpapers
Vertical (portrait) 16:9 rotated. The standard for smartphone screens and short-form vertical video content.
Common uses: TikTok, Instagram Reels, YouTube Shorts, Stories
The "classic" TV ratio from before widescreen. Still common in older projectors, standard definition video, and some print formats.
Common uses: Projectors, tablets, older video content
Perfect square. Used in social media profile pictures, app icons, and square print formats.
Common uses: Instagram squares, app icons, album art
The native ratio of most DSLR and mirrorless cameras (35mm film). Common in photography and standard photo prints.
Common uses: 6×4 prints, DSLR photos, 35mm photography
Ultrawide format. Used in cinema (2.39:1) and ultrawide gaming monitors. Gives a cinematic look to video.
Common uses: Ultrawide monitors, cinema, cinematic video
Divide the width by the ratio width and multiply by the ratio height. For 16:9 at 1920px wide: 1920 ÷ 16 × 9 = 1080px height. The calculator does this automatically when you lock the width.
YouTube thumbnails should be 16:9 at a minimum of 1280×720 pixels and under 2MB. YouTube displays thumbnails at 16:9 across all devices, so other ratios will result in cropping or black bars.
For Instagram feed posts, 4:5 (1080×1350) takes up the most screen space and performs best. For Reels and Stories, use 9:16 (1080×1920). For profile pictures and older feeds, 1:1 (1080×1080) works well.
Use the "Find Ratio from Dimensions" tab. Enter your image's width and height in pixels and the calculator instantly computes the simplified ratio, decimal ratio, and orientation (landscape, portrait, square).
Yes, completely free. All calculations run in your browser — no data sent to servers, no signup required, no limits.
Free · 10 Presets · Social Media Sizes · Visual Preview
📐 Open Aspect Ratio Calculator