Px to Em Converter
Convert pixels (px) to em units instantly for responsive CSS typography with this free online converter supporting custom base size, pt, and percentage equivalents.
About This Calculator
This free online px to em converter helps web designers and developers convert pixel values to relative em, points (pt), and percentage units for responsive CSS typography. Whether you are building a new website, updating an existing design system, or ensuring accessible scalable text, this tool handles all common CSS unit conversions in one click.
The conversion uses standard CSS unit relationships: 1em equals the base font size (default 16px), 1pt equals 0.75px, and 1em equals 100%. Simply enter your pixel value and optionally adjust the base font size to match your project's typography scale. The calculator instantly shows the equivalent in em, points, and percentage units.
Using relative units like em instead of fixed pixels is a best practice for accessible and responsive web design. Relative units respect user browser settings, scale proportionally across devices, and make it easier to maintain consistent proportions throughout your design system.
Regional Notes
Global: The px and em units are standard CSS units defined by the W3C and work identically across all browsers and regions worldwide. The default browser font size of 16px is consistent across all major browsers (Chrome, Firefox, Safari, Edge) regardless of region.
Accessibility: Many users globally rely on browser zoom or custom font sizes. Using em units ensures your content scales properly for users with visual impairments, making your website more accessible across all regions.
Frequently Asked Questions
How do I convert px to em?
To convert pixels (px) to em, divide the pixel value by the base font size. For example, if the base size is 16px (browser default), then 32px equals 2em because 32 ÷ 16 = 2. You can also set a custom base size to match your project's typography scale.
What is the default base size for px to em conversion?
The default base font size is 16px, which matches the standard browser default for most desktop browsers. However, you can adjust this value in the calculator to match your project's base font size, which is typically defined in the html or body CSS rule.
What is the difference between em and rem units?
The em unit is relative to the font size of its nearest parent element, while rem (root em) is relative to the root (html) element's font size. This makes rem more predictable and easier to manage in complex layouts, while em can cascade and compound when nested.
How do I convert px to pt?
To convert pixels (px) to points (pt), multiply the pixel value by 0.75. For example, 16px equals 12pt because 16 × 0.75 = 12. Points are traditionally used in print media, while pixels are the standard for digital screens.
Why should I use em instead of px in CSS?
Using em units in CSS makes your typography scalable and more accessible. Users who change their browser's default font size will see your content scale proportionally. Em units also allow for responsive designs that adapt better across different screen sizes and devices.
Can I use this converter for mobile responsive design?
Yes, this px to em converter is ideal for responsive web design. By converting fixed pixel values to relative em units, your typography and spacing will scale automatically across mobile, tablet, and desktop screens. Set your base font size to match each breakpoint's typography scale for consistent results.
What is the formula for px to percentage conversion?
To convert pixels to percentage, first convert px to em (px ÷ base size), then multiply by 100. For example, if the base size is 16px and your element is 32px, the result is 200% because (32 ÷ 16) × 100 = 200%. This matches the em value where 1em equals 100%.
How many pt is 16px equal to?
16px is equal to 12pt. The conversion factor is 1pt = 0.75px, so 16px × 0.75 = 12pt. This is a standard relationship used in both print and digital typography, where 1 inch equals 72pt and 96px at standard screen resolution.