Aspect ratios
4:3 Aspect Ratio Calculator & Resolution Guide
Find exact 4:3 dimensions such as 1024×768, calculate a missing side, and compare cropping and padding to widescreen.
A 4:3 frame is four units wide and three units high. Its decimal width-to-height ratio is 1.3333 recurring. It is more square than 16:9, but it is not a square. Enter a desired width below to find the matching height.
Resize With This Ratio — 4:3
Change either side. The other updates proportionally. Results show whole pixels and the exact value before rounding.
Exact height: 768 px
How the ratio is calculated
1024 ÷ 256 = 4; 768 ÷ 256 = 3. Dividing both sides by the same value preserves the proportions and gives 4:3. 256 is the greatest common divisor of these dimensions.
Height = width × 3 ÷ 4. Width = height × 4 ÷ 3. These formulas change size without changing shape. They do not crop or pad the source.
Recognizing a true 4:3 size
640 × 480, 800 × 600, 1024 × 768 and 1600 × 1200 are exact 4:3 dimensions. For 1024 × 768, divide both sides by 256 to obtain 4:3. A 1920 × 1080 frame is 16:9 instead, even though both are landscape resolutions.
Photographs and older screen layouts
The squarer shape can suit a composition with more vertical detail, such as a person seated at a desk. It also appears in older display and television formats. Choosing it for a photograph is a composition decision, not a claim that it contains more detail than a widescreen image.
Moving to 16:9 without distortion
At 1440 × 1080, a centered 16:9 crop keeps 1440 × 810 and removes 135 pixels from the top and bottom. Padding instead keeps all the source and extends the canvas to 1920 × 1080. Stretching to that size changes the proportions of faces, circles and objects.
See what changes when you fit 1440 × 1080 into 16:9
Both diagrams use the same source dimensions. Blue represents source content kept in the result; gray represents discarded edges or added canvas. These are geometric examples, not uploaded photographs.
Choose the result by checking the subject
- Open the source dimensions in the calculator and confirm width comes first.
- Compare the crop with your original image. If a face, caption or important detail crosses the removed region, reposition the crop or choose padding.
- Apply the selected dimensions in your editor. This tool calculates geometry; it does not change or download your file. Fractional sizes need whole-pixel rounding and the final ratio may be approximate.
A diagram cannot decide composition or platform eligibility. Check the exported file in its destination, and avoid stretching the dimensions independently. Read our calculation method and corrections process.
4:3 resizing examples
| Width | Exact height | Rounded height |
|---|---|---|
| 320 px | 240 px | 240 px |
| 640 px | 480 px | 480 px |
| 1080 px | 810 px | 810 px |
| 1920 px | 1440 px | 1440 px |
Decimal heights are displayed to four decimal places. Rounding can change the final ratio slightly. For an exact integer result, use dimensions that are whole-number multiples of 4:3.