PX to Rem Converter

Free online tool to Convert Pixel (PX) to REM. Convert bidirectionally with EM, Point and Percent.

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Base size in px. Default







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CSS Style Properties


h1 {

font-size: 1em;



h1 {

font-size: 16px;



h1 {

font-size: 1rem;



h1 {

font-size: 100%;



h1 {

font-size: 12pt;


Unit Conversion Table (Base 16)


What is px to REM online converter?

A Pixel-to-Root Em (PX to REM) conversion utility serves as a valuable instrument designed to transform pixel (px) measurements into root em (rem) units. In the realm of Cascading Style Sheets (CSS), this tool assumes particular significance, facilitating the creation of responsive designs that seamlessly accommodate diverse screen dimensions and resolutions. Its primary function lies in the establishment of the rem value, derived from the pixel value, thereby streamlining the process of designing adaptable and visually consistent web interfaces across a multitude of devices and display settings.

What can you do with PX to REM Converter Tool?

The PX to REM Converter Tool serves as a versatile instrument for several critical tasks:

  • Conversion of Pixel Values to REM Units: This tool facilitates the seamless translation of pixel measurements into relative em units, which can be seamlessly integrated into cascading style sheets (CSS). This capability proves particularly invaluable in the realm of responsive web design, enabling the creation of layouts that dynamically adapt to diverse screen dimensions and resolutions.
  • Proportional Scaling Relative to Root Font Size: Leveraging REM values, designers can achieve proportional scaling of elements in accordance with the font-size of the root element. This empowers the customization of font sizes and layout proportions to accommodate user preferences, including those necessitated by accessibility considerations.
  • Enhanced Accessibility Across Varied User Environments: By incorporating REM values, websites become more accessible to individuals employing screens of varying sizes and resolutions, as well as those with distinct font-size preferences. This inclusivity enhances the user experience, aligning with best practices in web accessibility.
  • Efficient Maintenance of Project Consistency: In the context of larger-scale projects, the application of REM values ensures the preservation of element proportions across the entirety of the endeavor. This simplifies the process of updating font sizes, as adjustments propagate uniformly throughout the project, eliminating the need for discrete alterations on a per-element basis.
  • Platform Agnostic Functionality: The free online PX to REM converter tool boasts compatibility with an array of operating systems, including Windows, MAC, Linux, and browsers such as Chrome, Firefox, Edge, and Safari. This broad support ensures accessibility to a wide user base, regardless of their chosen computing environment.

What is the difference Between PX and REM?

PX are absolute units that remain constant in size. It is the smallest addressable element in a raster image . On the other hand, Rem is usually used in CSS development. The Rem unit lets you define a size relative to the HTML root element's font-size.

To understand the distinction between px (pixel) and rem (root ems), you must first understand what they are and how they behave. To begin with, they are measurements that are used on screen media or screens on various devices. In CSS, they are commonly used to measure lengths (Cascading Style Sheets).

The distinction is that px is a fixed-size unit. If you say this font is 16px, it is exactly 16px no matter where you put it. It's just that different devices may show it differently. A 16px font displayed on your computer monitor may appear differently on your mobile phone.

Root em (rem) units, in contrast, are a type of relative measurement. They are determined by the font size of the webpage's root element, typically the HTML tag. When an element is defined with a specific number of rem units, it scales with the text size on the page. For instance, with a root element font size of 16px, 1rem equals 16px. If you assign an element a font size of 2rem, it becomes 32px. If you change the root element's font size to 20px, 1rem equals 20px, and a 2rem element equates to 40px.

Using rem units offers the benefit of creating a uniform layout that adapts to users' font size preferences, enhancing accessibility. PX units come in handy when precision is required for specific element sizes, often used in UI design like buttons and icons. On the other hand, REM units are commonly employed in typography, allowing font size to accommodate user font choices.

What is px to REM converter used for?

The PX to REM converter, available on the LambdaTest platform, serves as a valuable tool for web developers and designers seeking to achieve responsive and scalable design elements. This online converter seamlessly transforms pixel values into their corresponding measurements in REM (Root Em) and EM (Em) units.

By inputting a specific pixel width dimension, users can readily obtain the equivalent value expressed in REM and EM units, facilitating the creation of adaptive and fluid designs within a web environment. This conversion capability is particularly pertinent in the context of web development, where REM units are used to ensure consistent and accessible typography and spacing, catering to a diverse range of display sizes and resolutions. The PX to REM converter simplifies this process and empowers designers and developers to maintain design consistency and accessibility across various viewing contexts.

How to Use PX to REM Converter

Using a PX to REM converter is a fundamental step in achieving a responsive and accessible web design. To employ this tool effectively, follow these meticulous steps:

  • Determine Root Font Size:
  • Check the root font size specified in your CSS. If it's not explicitly defined, the default browser font size is typically 16px. This root size is essential as REM values are relative to it.

  • Identify PX Values:
  • Identify the font sizes you wish to convert from PX to REM in your CSS stylesheet.

  • Use a Converter Tool:
  • There are various online tools or converters available that help in converting PX to REM values. These tools usually require you to input the pixel value and the root font size. They will then generate the corresponding REM value.

  • Replace PX Values in CSS:
  • Once you have the converted REM values, replace the original PX values in your CSS with the new REM values. For instance, if you had a font size set to font-size: 16px; and the equivalent REM value is 1rem, replace it with font-size: 1rem;.

  • Ensure Compatibility:
  • Test the updated REM values across different browsers and devices to ensure they display consistently and adapt properly to varying user settings.

Benefits of Using PX to REM Converter

Using a PX to REM converter offers several benefits, especially in web development and design practices:

  • Ease of Conversion: Conversion tools simplify the process of converting PX (pixel) values to REM (root em) units. They provide a straightforward way to convert existing pixel-based measurements to a more flexible and scalable REM unit system.
  • Scalability and Responsiveness: REM units are relative to the root font size, making them highly scalable. Using a converter allows designers and developers to swiftly adapt existing pixel-based font sizes to REM, ensuring responsiveness across various devices and screen sizes.
  • Consistency in Design: By converting pixel-based font sizes to REM, consistency in design is maintained. REM units allow for better control over typography, ensuring that font sizes are proportionally adjusted based on the root font size, creating a harmonious and consistent visual hierarchy.
  • Accessibility and User Experience: REM units enhance accessibility by allowing font sizes to adapt to user preferences. Users can adjust browser settings for font size or utilize assistive technologies, and the converted REM units ensure that the content remains readable and accessible.
  • Maintenance and Future Updates: Utilizing a PX to REM converter streamlines maintenance and updates across a website. When the root font size is adjusted, all REM-based font sizes update proportionally, reducing the effort needed to maintain consistent typography throughout the site.
  • Responsive Typography: Responsive web design heavily benefits from using REM units. The converter facilitates the transition from fixed pixel sizes to responsive REM sizes, ensuring that typography adapts seamlessly to different viewport sizes without compromising readability or design integrity.
  • Cross-Browser Compatibility: REM units have good support across modern browsers. By using a converter, developers ensure that the REM-based font sizes are applied consistently across different browsers, providing a uniform user experience.
  • Flexibility in Designing: PX to REM conversion offers flexibility in designing layouts and typography. It allows for greater control over font sizes while enabling a design that adapts fluidly to user preferences and different devices.

Frequently Asked Questions

  • Which is better px or REM?
  • Both `px` and `rem` have their merits. `px` provides a fixed value, while `rem` is relative to the root element's font size. `rem` is preferred for accessibility and scalability, as it adjusts based on user preferences. Ultimately, the choice depends on the specific project requirements and design considerations.

  • How big is 1 rem in px?
  • 1 rem is equivalent to the font size of the root element (usually the html element) in a document, relative to which other font sizes are defined. It is not directly convertible to pixels (px) as it depends on the user's browser settings. However, it provides a flexible and accessible way to manage typography in web design.

  • What is 20px in rem?
  • 20px in rem units depends on the root font size (usually set by the browser). If the root font size is 16px, 20px would be 1.25rem (20 ÷ 16 = 1.25). This ensures scalability based on user preferences and accessibility. Always consider using relative units like rem for better responsiveness in web design.

  • Is 16px equal to rem?
  • No, 16px is not equivalent to 1rem by default; it depends on the root font size defined in the CSS.

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