4:3 Aspect Ratio Calculator
Calculate 4:3 aspect ratio dimensions from width or height. Get width, height, simplified ratio, diagonal, area, megapixels, and nearest common resolution with interactive charts.
Enter either width or height (or both). The calculator computes the missing dimension at 4:3 ratio.
About This Calculator
The 4:3 Aspect Ratio Calculator helps you compute display and image dimensions at the classic 4:3 ratio. Enter either the width or height in pixels, and the calculator instantly returns the missing dimension while maintaining the exact 4:3 proportion. You can also enter both dimensions to verify the aspect ratio.
4:3 was the standard aspect ratio for CRT televisions, computer monitors (VGA through UXGA), and projectors before the widespread adoption of widescreen 16:9 displays. It remains important in photography (especially Micro Four Thirds and medium format cameras), medical imaging, retro gaming, and certain industrial and presentation applications.
The formula used is: Height = Width × ¾ (when width is known) or Width = Height × ⁴⁄₃ (when height is known). The diagonal is computed using the Pythagorean theorem: Diagonal = √(Width² + Height²), which for 4:3 always follows the 3-4-5 triangle relationship. The total pixel count (area) is Width × Height, converted to megapixels by dividing by 1,000,000.
Regional Notes
The 4:3 aspect ratio is a global standard used worldwide. While 16:9 has become the dominant consumer display ratio, 4:3 remains relevant in professional photography, medical imaging, and industrial applications across all regions. Resolution naming conventions (VGA, SVGA, XGA, etc.) are consistent internationally.
Frequently Asked Questions
What is a 4:3 aspect ratio?
4:3 is a standard aspect ratio where the width is 1.33 times the height. It was the dominant ratio for CRT televisions, computer monitors, and projectors before the widescreen 16:9 standard became popular. Common 4:3 resolutions include 640×480, 800×600, 1024×768, 1280×960, and 1600×1200.
How do I calculate 4:3 aspect ratio dimensions?
If you know the width, multiply by 3/4 to get the height. If you know the height, multiply by 4/3 to get the width. For example, a width of 1024 pixels gives a height of 1024 × 3/4 = 768 pixels, resulting in the common 1024×768 4:3 resolution.
What are common 4:3 resolutions?
Common 4:3 resolutions include 640×480 (VGA), 800×600 (SVGA), 1024×768 (XGA), 1152×864, 1280×960 (SXGA), 1400×1050 (SXGA+), 1600×1200 (UXGA), 1920×1440, and 2048×1536 (QXGA). These resolutions maintain the 4:3 width-to-height ratio.
Is 4:3 still used today?
Yes, 4:3 is still used in photography (Micro Four Thirds cameras, some medium format), medical imaging displays, industrial monitors, older projectors, retro gaming, and some tablet devices like the iPad (9.7-inch models). Many document cameras and presentation systems also use 4:3.
How do I calculate the diagonal of a 4:3 screen?
The diagonal of a 4:3 screen is calculated using the Pythagorean theorem: diagonal = √(width² + height²). For a 4:3 ratio, the diagonal is exactly 5 units when width is 4 units and height is 3 units (a 3-4-5 triangle). For example, a 1024×768 display has a diagonal of approximately 1280 pixels.
What is the difference between 4:3 and 16:9 aspect ratios?
4:3 (1.33:1) is more square and was standard for older TVs and monitors, while 16:9 (1.78:1) is wider and is the modern standard for HDTVs, monitors, and streaming video. 4:3 has 75% of the width relative to height compared to 16:9, making it less suitable for widescreen cinematic content but better for productivity and document viewing.
How do I convert 16:9 content to 4:3?
To convert 16:9 content to 4:3, you can either crop the sides (losing some of the image) or add black bars (pillarboxing) on the left and right. For cropping, keep the center portion of the frame. For pillarboxing, maintain the original resolution and add black bars to fill the 4:3 frame.
What is the megapixel count of common 4:3 resolutions?
Common 4:3 megapixel counts: 640×480 = 0.31 MP, 800×600 = 0.48 MP, 1024×768 = 0.79 MP, 1280×960 = 1.23 MP, 1600×1200 = 1.92 MP, 1920×1440 = 2.76 MP, 2048×1536 = 3.15 MP. The 4:3 ratio is commonly used in camera sensors, especially in Micro Four Thirds and medium format systems.