A ratio calculator helps you solve proportional relationships and scale values while maintaining their relative proportions. Whether you need to resize images while preserving aspect ratio, convert recipe quantities for different serving sizes, calculate scale factors for engineering drawings, or simplify ratios to their lowest terms, this free online tool provides instant results. Enter known values and let the calculator find the missing number. The built-in image resize feature makes it especially useful for designers and developers who need to scale graphics while maintaining proper dimensions.
Types of Ratio Calculations
This tool handles several types of proportional calculations: solving for unknown values in A:B = C:D equations (cross-multiplication); simplifying ratios to their lowest terms using greatest common divisor; proportional scaling where you know one dimension and need to find the other; aspect ratio calculation from given width and height values. Each calculation type serves different practical needs from mathematics homework to professional design work.
Common Aspect Ratios Reference
- 16:9 - Standard widescreen for HD/4K TVs, monitors, and YouTube videos
- 4:3 - Traditional TV and older computer monitors
- 21:9 - Ultrawide monitors and cinematic displays
- 1:1 - Square format, popular for social media posts
- 3:2 - Digital SLR photography standard
- 9:16 - Vertical video for mobile stories and TikTok
Image Resizing with Aspect Ratio Lock
When resizing images, maintaining the original aspect ratio prevents distortion. Simply enter the original width and height, then specify either the new width or new height. The calculator automatically computes the other dimension to preserve proportions. The lock feature ensures you cannot accidentally create stretched or squished images. This is essential for web designers, social media managers, and anyone preparing graphics for different platforms.
Practical Applications
Ratio calculations appear everywhere: architects use scale ratios for blueprints (1:100 means 1cm represents 100cm); photographers crop images to specific aspect ratios for prints; chefs scale recipes by multiplying all ingredients by the same ratio; investors calculate portfolio allocation ratios; mixologists maintain consistent drink proportions; map makers use scale factors to represent distances accurately.
FAQ
Q: How do I maintain aspect ratio when resizing an image?
A: Enter your original width and height, then specify only the new width OR new height (not both). The calculator uses the formula: New Height = Original Height x (New Width / Original Width). This ensures the image scales proportionally without stretching or squishing.
Q: How do I simplify a ratio to its lowest terms?
A: Find the greatest common divisor (GCD) of both numbers and divide each by it. For example, 1920:1080 - the GCD is 120, so dividing both gives 16:9. This tool calculates simplified ratios automatically when you enter values.
Q: What is the golden ratio and when should I use it?
A: The golden ratio is approximately 1:1.618 (often written as phi or the Greek letter phi). It appears throughout nature and art, and many consider it aesthetically pleasing. Designers use it for layouts, typography, and composition. While not included as a preset, you can calculate with it by entering 1 and 1.618 as your ratio values.
Q: Can I use this for recipe conversions?
A: Absolutely! If a recipe serves 4 people and you need to serve 6, the ratio is 4:6 (or 2:3). Enter the original quantity for any ingredient and the calculator will give you the scaled amount. This works for any proportional scaling needs.