Pixel360Free design calculators and converters
Free, fast calculators and converters for web designers, developers and anyone working with screens, images and color.
Unit converters
- PX to REM ConverterConvert pixels to rem for any root font size, with a full conversion table.
- REM to PX ConverterTurn rem values back into pixels for any base font size.
- PX to EM ConverterConvert pixels to em relative to the parent element font size.
- PX to VW ConverterConvert pixels to viewport width units for any screen width.
Images & screens
- Aspect Ratio CalculatorFind the ratio of any size, or the missing width or height.
- Image Resize CalculatorScale an image by width, height or percentage without distortion.
- PPI CalculatorPixel density of any screen from its resolution and diagonal size.
- DPI & Print Size CalculatorHow big an image prints at a given DPI, and the pixels you need.
- Golden Ratio CalculatorSplit a length by the golden ratio (1.618) for layouts and type.
Color
CSS generators
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Guides
- PX vs REM vs EM vs VW: Which CSS Unit to UseWhen to use each CSS length unit, with real examples.
- DPI vs PPI: What’s the Difference?Screen pixels, printer dots and why the terms get mixed up.
- WCAG Color Contrast Requirements ExplainedAA vs AAA, large text, UI components and how to fix failures.
- Fluid Typography: A Practical GuideType that scales smoothly between phone and desktop.
- How to Make Images Sharp on Retina ScreensDevice pixel ratio, srcset and the sizes to export.
- CSS Color Formats: HEX, RGB, HSL and OKLCHWhat each format is for and when to switch.
Why designers use Pixel360
Every tool here does one job quickly: convert units, size images, check color contrast or write fluid CSS. Results update as you type, everything runs in your browser, and each page explains the formula with worked examples so you know the number is right.