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Image Ratio Calculator
Calculate aspect ratios, scale proportionally, preview common sizes, and detect image dimensions. Supports 4 modes with real-time results and visual preview.
Decimals:
Calculate aspect ratio from width and height
×
Image Detection
📷
Drag & drop image here
or Browse files
Preview
16:9
Calculation Examples
| Question | Method | Result |
|---|---|---|
| 1920 × 1080 ratio? | GCD(1920,1080)=120 | 16:9 |
| Scale 1920×1080 to width 1280 | 1280×1080÷1920 | 1280×720 |
| 4:5 ratio, width 1080, height? | 1080×5÷4 | 1350 |
| 3:2 ratio, height 800, width? | 800×3÷2 | 1200 |
| Is 1080×1920 a known ratio? | GCD=1080 | 9:16 |
| YouTube thumbnail size? | Preset | 1280×720 |
About This Tool
This image ratio calculator supports four modes: calculating aspect ratios from dimensions, proportional scaling, looking up common ratios, and checking platform-specific sizes. It also detects image dimensions from uploaded files. All processing runs locally in your browser.
How to Use
- 1Select a mode from the tabs at the top.
- 2Enter width and height values.
- 3Results update in real time.
- 4Use Swap to exchange width and height.
- 5Upload an image to auto-detect its dimensions.
Calculation Rules
Aspect Ratio
Divide both width and height by their greatest common divisor (GCD).
Proportional Scaling
New height = new width × original height ÷ original width.
Reverse Scaling
New width = new height × original width ÷ original height.
Orientation
Width > height = landscape; width < height = portrait; equal = square.
Megapixels
Total pixels = width × height. Megapixels = total pixels ÷ 1,000,000.
Rounding
Scaled dimensions are rounded to the nearest integer.
Limitations
- ⚠ Calculations are mathematical only; they do not modify actual images.
- ⚠ Supported upload formats: JPG, PNG, WebP, GIF, BMP.
- ⚠ SVG files require special handling and may not display correctly.
- ⚠ Very large images (>50MP) may be slow to process.
- ⚠ Results are rounded to integers; some ratios cannot produce exact pixel values.
Frequently Asked Questions
What is the difference between aspect ratio and dimensions?+
Aspect ratio describes the proportional relationship between width and height (e.g., 16:9). Dimensions are the actual pixel count (e.g., 1920×1080).
What ratio is 1920×1080?+
GCD(1920, 1080) = 120. 1920÷120 = 16, 1080÷120 = 9. The ratio is 16:9.
Does changing the ratio reduce image quality?+
Calculating ratios does not alter the image. Actual resizing, compression, or re-encoding may affect quality.
Why do some results have decimal places?+
Some target ratios cannot produce integer pixel values. Results are rounded to the nearest pixel.
What is the difference between cropping and proportional scaling?+
Proportional scaling preserves the entire image. Cropping removes parts of the image to fit a new ratio.
Are uploaded images saved?+
No. All image processing runs entirely in your browser. Nothing is uploaded to any server.
Related Tools
Related Articles
- 📄 Understanding aspect ratios and how to calculate them
- 📄 Common image sizes for social media platforms
- 📄 How to proportionally resize images without distortion
- 📄 Difference between aspect ratio and resolution
- 📄 Guide to image megapixels and quality