Aspect Ratio Calculator
What are the most common aspect ratios and their uses?
| Ratio | Decimal | Common Use |
|---|---|---|
| 16:9 | 1.778 | HD video, YouTube, TV, monitors, presentations |
| 4:3 | 1.333 | Older TV, iPad (non-Pro), standard monitors |
| 1:1 | 1.000 | Instagram square, profile pictures, album art |
| 9:16 | 0.5625 | TikTok, Instagram Reels, YouTube Shorts, Stories |
| 3:2 | 1.500 | 35mm film, DSLR photos, some digital cameras |
| 4:5 | 0.800 | Instagram portrait posts |
| 2.35:1 | 2.350 | Anamorphic widescreen cinema |
| 21:9 | 2.333 | Ultrawide monitors, some modern cinema |
Standard screen resolutions by ratio
- 16:9: 1280×720 (720p), 1920×1080 (1080p), 2560×1440 (1440p), 3840×2160 (4K)
- 4:3: 800×600, 1024×768, 1400×1050
- 1:1: 1080×1080, 1200×1200
Frequently asked questions about aspect ratios
What happens if I resize an image without maintaining the aspect ratio? The image is stretched or squashed — people and objects look unnaturally wide or tall. Always resize proportionally unless you specifically intend to change the composition for a different platform format. Need to continue this calculation? Try the Unit Converter or the Paint Calculator.
What is the best ratio for social media profile pictures? Most platforms display profile pictures as circles cropped from squares. The source image should be 1:1 (square) at minimum 400×400 pixels (Facebook, Twitter), 500×500 pixels (LinkedIn), or 110×110 pixels minimum (Instagram).
What are the correct image dimensions for social media?
| Platform | Content Type | Size (px) | Ratio |
|---|---|---|---|
| Square post | 1080×1080 | 1:1 | |
| Portrait post | 1080×1350 | 4:5 | |
| Story / Reel | 1080×1920 | 9:16 | |
| Post image | 1200×630 | 1.91:1 | |
| Twitter / X | Post image | 1200×675 | 16:9 |
| Post image | 1200×627 | 1.91:1 | |
| YouTube | Thumbnail | 1280×720 | 16:9 |
| YouTube | Channel banner | 2560×1440 | 16:9 |
| TikTok | Video | 1080×1920 | 9:16 |
| Pin image | 1000×1500 | 2:3 |
Which screen resolutions match each aspect ratio?
| Ratio | Common Resolutions | Use Cases |
|---|---|---|
| 16:9 | 1280×720, 1920×1080, 3840×2160 | TV, YouTube, monitors, presentations |
| 4:3 | 800×600, 1024×768 | Older monitors, iPad, PowerPoint legacy |
| 1:1 | 1080×1080, 1200×1200 | Instagram, profile pictures, album art |
| 9:16 | 1080×1920 | TikTok, Stories, Reels, Shorts, phone screens |
| 3:2 | 1440×960, 6000×4000 | DSLR cameras, MacBook screens |
What aspect ratio should I use for YouTube? 16:9 is the YouTube standard for all horizontal videos. Record at 1920×1080 minimum; 3840×2160 (4K) if your camera supports it. YouTube letterboxes non-16:9 videos with black bars, making 16:9 the correct choice for all standard uploads.
What happens if I resize without maintaining aspect ratio? Objects appear stretched or squashed. People look distorted, circles become ovals, and text may be unreadable. Always resize proportionally unless deliberately reformatting content for a different platform shape.
What is the best ratio for print photos? Standard 4×6 inch prints use 3:2 ratio. 5×7 uses 5:7. 8×10 uses 4:5. A 16:9 image printed at 8×10 will have significant cropping or white borders. Shoot in the aspect ratio matching your intended print size for best results.
What aspect ratio should you use for YouTube, Instagram, and print?
| Platform / Format | Ratio | Pixels (common) | Notes |
|---|---|---|---|
| Widescreen HD / Full HD | 16:9 | 1920×1080 | YouTube, most monitors, TV |
| Ultra-wide monitor | 21:9 | 2560×1080 | Gaming, cinematic video |
| Standard monitor / photo | 4:3 | 1024×768 | Classic TV, older cameras |
| Square (social) | 1:1 | 1080×1080 | Instagram post, Facebook |
| Instagram portrait | 4:5 | 1080×1350 | Best reach on feed |
| Instagram / TikTok story | 9:16 | 1080×1920 | Full-screen vertical |
| Twitter / X image | 16:9 | 1200×675 | In-feed image preview |
| LinkedIn post image | 1.91:1 | 1200×627 | Landscape share image |
| Facebook cover photo | 2.7:1 | 820×312 | Desktop; 640×360 mobile |
| YouTube thumbnail | 16:9 | 1280×720 | Max 2MB, JPG/PNG/GIF |
| A4 paper (portrait) | 1:√2 ≈ 1:1.414 | 2480×3508 (300dpi) | ISO 216 standard |
| US Letter paper | 17:22 | 2550×3300 (300dpi) | 8.5×11 inches |
| Cinema (DCI 4K) | 256:135 ≈ 1.9:1 | 4096×2160 | Professional cinema standard |
| Anamorphic cinema | 2.39:1 | 4096×1714 | Widescreen cinematic look |
What screen resolutions do phones, tablets, and monitors use?
| Device | Resolution | Ratio | PPI (approx.) |
|---|---|---|---|
| iPhone 15 Pro | 2556×1179 | 19.5:9 | 460 ppi |
| Samsung Galaxy S24 | 2340×1080 | 19.5:9 | 416 ppi |
| iPad Pro 12.9" (M4) | 2752×2064 | 4:3 | 264 ppi |
| MacBook Pro 16" | 3456×2234 | ~1.5:1 | 254 ppi |
| 4K UHD TV | 3840×2160 | 16:9 | Depends on size |
| 8K TV | 7680×4320 | 16:9 | Depends on size |
Sources & References
Sources: SMPTE ST 2036-1 — Ultra High Definition Television; ISO 216 — paper size standard (A-series); Meta/Instagram content specifications 2026; YouTube creator academy.
Common aspect ratios by use case
| Aspect Ratio | Common Use | Examples |
|---|---|---|
| 16:9 | Widescreen video, HD/4K displays, YouTube | 1920×1080, 2560×1440, 3840×2160 |
| 4:3 | Old TV, standard monitors, early digital cameras | 800×600, 1024×768, 640×480 |
| 1:1 | Instagram square posts, profile pictures | 1080×1080, 720×720 |
| 9:16 | Vertical video, Instagram/TikTok Stories, Reels | 1080×1920 (portrait HD) |
| 21:9 | Ultrawide monitors, cinematic film | 2560×1080, 3440×1440 |
| 2:3 (3:2) | 35mm film photography, DSLR sensors | 4000×6000, A4 paper (approximately) |
| 4:5 | Instagram portrait posts | 1080×1350 |
| 2.39:1 | Widescreen cinema (anamorphic) | Black bars visible on 16:9 screens |
Calculating new dimensions while preserving aspect ratio
To resize an image without distortion: new height = (original height ÷ original width) × new width. Original: 1920×1080 (16:9). Resize to 1280 wide: new height = (1080÷1920) × 1280 = 0.5625 × 1280 = 720px. Result: 1280×720 — same 16:9 ratio. The aspect ratio calculator does this automatically for any input dimensions. Letterboxing (black bars top and bottom) occurs when displaying 16:9 content on a 4:3 screen — the 16:9 image fits within the 4:3 frame with bars filling the remaining height. Pillarboxing is the reverse — 4:3 content with bars on the sides when displayed on 16:9. Related: Word Counter.
Common aspect ratios and where they are used
| Aspect Ratio | Used In | Common Resolutions |
|---|---|---|
| 16:9 | HD/4K TV, YouTube, most monitors | 1280×720, 1920×1080, 3840×2160 |
| 4:3 | Old CRT TVs, iPad (some), Zoom calls | 800×600, 1024×768, 2048×1536 |
| 21:9 | Ultrawide monitors, cinema | 2560×1080, 3440×1440 |
| 9:16 | Instagram Reels, TikTok, mobile video | 1080×1920 |
| 1:1 | Instagram posts, profile photos | 1080×1080 |
| 3:2 | DSLR cameras, 4×6 inch prints | 6000×4000 |
How to maintain aspect ratio when resizing images or video
To maintain aspect ratio when resizing: new height = (new width ÷ original width) × original height. Example: resize a 1920×1080 image to 800px wide: height = (800 ÷ 1920) × 1080 = 450px. Result: 800×450 — still 16:9, no distortion. For video: letterboxing places black bars top and bottom when a widescreen video plays in a narrower frame. Pillarboxing places black bars left and right when a 4:3 video plays in a 16:9 frame. Understanding aspect ratios prevents distortion across devices, platforms, and print sizes. Related: Percentage Calculator