Formula and method
Whole-number dimensions are divided by their greatest common divisor. For decimal dimensions, the calculator also reports width ÷ height so uncommon ratios remain meaningful.
Assumptions and limits
- Manual width and height describe the same unit.
- Image files are read locally and are never uploaded.
- Fit preserves the whole image; crop fills the target and removes overflow.
Worked examples
1920 × 1080 video
The greatest common divisor is 120. Dividing both dimensions by 120 gives the familiar 16:9 ratio.
4032 × 3024 photo
Both values divide by 1008, giving 4:3. At a target width of 1600 pixels, the proportional height is 1200 pixels.
Width Height Ratio Calculator
Use width and height from any consistent unit: pixels, inches, centimeters or millimeters. The calculator reduces both values by their greatest common divisor when the inputs are whole numbers.
This is useful when you need to compare a photo, screen, poster or design frame without caring about the original unit.
Crop Ratio Calculator
The crop result shows the dimensions needed to completely cover the target box while preserving the original aspect ratio. Anything outside that covered area can be cropped away.
Use fit when the whole image must remain visible, and crop when the target frame must be filled edge to edge.
Aspect Ratio in Inches
Aspect ratio is unitless, so inches work the same way as pixels. A 16 x 9 inch frame, a 1920 x 1080 image and a 3840 x 2160 video all reduce to 16:9.
For print planning, calculate the ratio first, then use the print size calculator if you also need PPI and physical output size.
Common aspect ratios and crop targets
| Ratio | Decimal | Common use |
|---|---|---|
| 1:1 | 1.000 | Square avatars, product thumbnails and social posts |
| 3:2 | 1.500 | DSLR photos and classic 4x6 prints |
| 4:3 | 1.333 | Phone photos, cameras and presentation slides |
| 16:9 | 1.778 | Video, TVs, monitors and thumbnails |
| 21:9 | 2.333 | Ultrawide banners and cinematic crops |
Frequently asked questions
Does uploading an image send it anywhere?
No. The browser reads only its local dimensions. The file is not uploaded or stored.
What is the difference between fit and crop?
Fit keeps the complete image and may add empty space. Crop fills the target area and trims the extra width or height.
How do I keep an image from stretching?
Use proportional resizing. Change either width or height and let the calculator derive the other dimension from the original ratio.
Why does 1920 x 1080 become 16:9?
Both numbers divide evenly by 120. The reduced width and height are therefore 16 and 9.
Can I use this as a width height ratio calculator?
Yes. Enter the width and height to reduce them to the simplest ratio, then use the decimal value for comparison or layout checks.
How does the crop ratio calculator work?
Crop mode scales the image until it fills the target box, then shows the dimensions that cover the box before trimming overflow.
Can I calculate aspect ratio in inches?
Yes. Use the same unit for width and height. A 12 x 8 inch print has the same 3:2 ratio as a 1200 x 800 pixel image.