Aspect Ratio Calculator: Calculate Width & Height From Any Ratio
Aspect ratio is the proportional relationship between width and height. Get it wrong and faces look stretched, logos appear warped, and videos show black bars. Our free aspect ratio calculator instantly finds the ratio from any dimensions — and calculates the correct width or height when you resize.
Quick Answer
To calculate aspect ratio from width and height: divide both by their GCD. Example: 1920÷120 = 16, 1080÷120 = 9 → ratio is 16:9. To resize keeping the ratio: new_height = (new_width ÷ original_width) × original_height.
What Is Aspect Ratio?
Aspect ratio is written as W:H (width to height). A 16:9 ratio means for every 16 units wide, the frame is 9 units tall. The actual pixel dimensions can vary — 1920×1080 and 1280×720 both have a 16:9 ratio. The ratio describes the shape of the frame, not its size.
To simplify a ratio, divide both numbers by their Greatest Common Divisor (GCD). For 1920×1080: GCD = 120, so 1920÷120 = 16 and 1080÷120 = 9, giving 16:9.
Common Aspect Ratios Reference
1.78:1
Widescreen HD — YouTube, HD video, TV, monitors, presentations
1920×1080, 1280×720, 3840×2160 (4K)
1.33:1
Standard / Legacy — Old monitors, photography, some print formats, iPad
1024×768, 800×600, 2048×1536
1.00:1
Square — Instagram feed posts, profile photos, app icons
1080×1080, 800×800, 512×512
0.56:1
Vertical / Portrait — TikTok, Instagram Stories & Reels, YouTube Shorts
1080×1920, 720×1280
1.50:1
Photography — 35mm film, DSLR cameras, print (4×6, 6×9 in)
3000×2000, 1500×1000
2.33:1
Ultrawide Cinematic — Ultrawide monitors, cinematic film, movie letterbox
2560×1080, 3440×1440
0.80:1
Portrait Feed — Instagram portrait posts (tallest allowed in feed)
1080×1350, 864×1080
2.00:1
Univisium / Twitter — Twitter/X header image, panoramic photography
1500×750, 2000×1000
How to Resize Without Distortion
When you resize an image or video, both dimensions must scale by the same factor to preserve the ratio. If they don't, you get distortion — stretched faces, oval circles, warped logos.
Formula: resize keeping aspect ratio
new_height = (new_width ÷ original_width) × original_height
new_width = (new_height ÷ original_height) × original_width
Resize Examples
1920×1080 (16:9)
800px wide
→ 800×450
1080×1080 (1:1)
400px wide
→ 400×400
3000×2000 (3:2)
1200px wide
→ 1200×800
1080×1920 (9:16)
540px wide
→ 540×960
2560×1080 (21:9)
1280px wide
→ 1280×540
1500×750 (2:1)
600px wide
→ 600×300
Aspect Ratios by Platform
Every social media platform has its own preferred dimensions. Using the wrong ratio means your content gets cropped, shows black bars, or appears stretched.
| Platform | Ratio | Recommended Size |
|---|---|---|
| YouTube | 16:9 | 1920×1080 (Full HD) or 3840×2160 (4K) |
| Instagram Feed | 1:1 or 4:5 | 1080×1080 (square) or 1080×1350 (portrait) |
| Instagram Stories / Reels | 9:16 | 1080×1920 |
| TikTok | 9:16 | 1080×1920 |
| X (Twitter) Image | 16:9 | 1200×675 |
| X (Twitter) Header | 3:1 | 1500×500 |
| Facebook Video | 16:9 | 1280×720 |
| LinkedIn Post | 1.91:1 | 1200×627 |
| Pinterest Pin | 2:3 | 1000×1500 |
| Zoom / Google Meet | 16:9 | 1920×1080 |
Print & Photo Aspect Ratios
Print formats follow different ratios than digital screens. Understanding these ratios prevents white borders or unexpected cropping when printing photos.
Standard photo print — most DSLRs shoot natively in this ratio
Portrait prints — slightly taller than 3:2, requires a small crop
Common framed print — crops the top/bottom of a 3:2 photo
International paper standard used in Europe and most of the world
Standard US paper — slightly different from A4
Scrapbooking and art prints
Free Aspect Ratio Calculator
Enter any width & height → get the ratio · Resize to new dimensions · Common presets · No sign-up
Open Aspect Ratio Calculator →Frequently Asked Questions
How do I calculate aspect ratio from width and height?
Divide both numbers by their Greatest Common Divisor (GCD). For example, 1920×1080: GCD is 120, so 1920÷120=16 and 1080÷120=9, giving 16:9. Our free calculator does this instantly — just enter the width and height.
What is 16:9 aspect ratio in pixels?
Common 16:9 pixel dimensions include: 3840×2160 (4K UHD), 1920×1080 (Full HD), 1280×720 (HD), 1024×576, and 854×480. Any resolution where width÷height ≈ 1.778 is 16:9.
How do I resize an image without changing the aspect ratio?
Multiply both the width and height by the same scale factor. If you want a 1920×1080 image at 800px wide: scale = 800÷1920 = 0.417. New height = 1080 × 0.417 = 450px. Result: 800×450. Our calculator does this automatically.
What aspect ratio should I use for YouTube?
YouTube's native aspect ratio is 16:9. The recommended resolution is 1920×1080 (Full HD) or 3840×2160 (4K). Other resolutions like 1280×720 and 2560×1440 also work as long as they are 16:9.
What is the aspect ratio for Instagram?
Instagram supports multiple ratios: 1:1 (square, 1080×1080) for feed posts, 4:5 (portrait, 1080×1350) for portrait feed posts, and 9:16 (1080×1920) for Stories and Reels.
What does aspect ratio mean?
Aspect ratio is the proportional relationship between width and height expressed as W:H. A 16:9 ratio means for every 16 units wide, the image is 9 units tall. It describes the shape of a frame, not its actual pixel size.
What is a size ratio calculator?
A size ratio calculator (also called an aspect ratio calculator) helps you find the ratio between width and height, or calculate a new width or height while maintaining the same proportions. Enter the original dimensions and a target width or height to get the result.
What is the aspect ratio of 1920×1080?
1920×1080 has a 16:9 aspect ratio. Divide both by their GCD (120): 1920÷120=16 and 1080÷120=9. This is the standard Full HD (1080p) resolution used by most monitors, TVs, and video content.
What is the aspect ratio of 1080×1080?
1080×1080 has a 1:1 aspect ratio (square). It's the standard square format used for Instagram feed posts, profile photos, and many app icons.
How do I find the height if I know the width and aspect ratio?
Multiply the width by the ratio's height component, then divide by the width component. For a 16:9 ratio at 1200px wide: height = 1200 × (9÷16) = 675px. Our calculator does this in one click.
What is the TikTok aspect ratio?
TikTok's standard aspect ratio is 9:16 (vertical portrait). The recommended resolution is 1080×1920 pixels. Landscape (16:9) and square (1:1) are also supported, but 9:16 performs best on the platform.
What is the Facebook video aspect ratio?
Facebook supports 16:9 (landscape, 1280×720 recommended) for regular videos, 9:16 for Stories and Reels, and 1:1 (square) for feed posts. Landscape 16:9 is the most universally compatible format.
Why do images look stretched or squashed?
Images appear stretched or squashed when they are resized with different scale factors for width and height — for example, making an image wider without making it taller in proportion. Always resize by the same multiplier in both dimensions, or use an aspect ratio calculator to find the correct dimensions.