🖥️Pixel Converter

This pixel converter and PX to REM converter handles every CSS unit you need for web and print work: pixels, rem, em, points, viewport units, centimeters, millimeters, and inches. Enter any value, choose your source and target units, and get an instant conversion along with a full reference table so you can see all equivalents at once.

Pixels to REM and EM Converter for Web Design

CSS offers two fundamentally different categories of length units. Absolute units such as pixels, points, and inches always render at the same physical size regardless of context. Relative units such as rem, em, and viewport-based units (vw and vh) scale based on some reference value, making them the foundation of responsive and accessible design.

Pixels are the most familiar absolute unit and serve as the universal conversion reference. A CSS pixel is defined at 96 pixels per inch for screen purposes, which is why 1 inch equals 96px in CSS, regardless of the actual display density. On high-DPI screens, the operating system handles the scaling transparently, so your CSS pixel values still work as expected even when a Retina or 4K display is rendering them with two or four physical pixels per CSS pixel.

The rem unit, short for root em, is relative to the font size of the root HTML element. Browsers default to 16px, making 1rem equal to 16px under default settings. The critical advantage of rem is that it respects the user's chosen browser font size. If a user increases their default text size for readability, rem-based values scale automatically. Pixels do not, which is why using pixels for font sizes is considered an accessibility concern. For any font-size property in your CSS, rem is the preferred unit in modern web development.

The em unit is relative to the font size of the current or parent element, depending on the property. This cascading behavior makes em powerful for component-level scaling but can produce unexpected compounding when elements are deeply nested. A grandchild element set to 1.5em inside a parent already set to 1.5em results in a font size 2.25 times the base, which is often unintended. Em is most useful for padding and margins that should proportionally track the text size of the element they surround.

Convert PX to Inches for Print

When preparing assets for print, the relationship between pixels and physical inches depends on the output resolution, measured in dots per inch (DPI) or pixels per inch (PPI). CSS defines the reference resolution as 96 DPI, so at 96 DPI one inch equals exactly 96px. That is the conversion this calculator uses for px-to-inches calculations.

Print design typically demands much higher resolution. A standard inkjet or laser printer outputs at 300 DPI, and high-quality print production sometimes requires 600 DPI. This means that a 96px image, which looks perfectly sharp on a screen, represents only 0.32 inches at 300 DPI and will appear quite small when printed. To produce a 4-inch-wide printed image at 300 DPI, you need 1,200 pixels of image width.

• Screen design: 96 DPI is the CSS reference. Pixel dimensions map directly to CSS pixel values.
• Standard print: 300 DPI is the baseline for sharp printed output. Multiply inches by 300 to get required pixel dimensions.
• High-quality print: 600 DPI for fine detail, such as photography and professional publishing.
• Large-format print: Banners and posters viewed from a distance can use 72 to 150 DPI without visible quality loss.

CSS Unit Converter PX, REM, EM, PT: Choosing the Right Unit

Points (pt) come from the print world: one point equals 1/72 of an inch. At 96 DPI, one point equals 1.333px. Points are appropriate in CSS print stylesheets where you want type to render at a precise physical size on paper. For screen-only work, points offer no practical advantage over pixels and introduce confusion because their physical meaning disappears on displays where DPI varies.

Viewport units (vw and vh) express a percentage of the browser window's width or height. A value of 100vw fills the full viewport width, and 50vh is half the viewport height. These units are excellent for fluid hero sections, full-screen overlays, and responsive typography using the CSS clamp() function. One well-known caveat is that 100vh can be unreliable on mobile browsers because the collapsible address bar changes the available height. The newer dvh (dynamic viewport height) unit resolves this problem in modern browsers.

For practical guidance on when to reach for each unit in your CSS work:

• Font sizes: Use rem so typography respects user accessibility settings.
• Component spacing (padding, margin): Use em to keep spacing proportional to the local font size, or rem for consistent spacing regardless of nesting.
• Borders and shadows: Use px for precise visual detail that should not scale with text.
• Layout widths and heights: Use percentage, vw, or vh for fluid, responsive layouts.
• Print stylesheets: Use pt or cm to specify physically meaningful sizes.