PX to EM Converter
Convert pixels to EM units instantly with this free online tool. Perfect for CSS styling and scalable typography. Enter pixel values, adjust parent font size, and get accurate EM conversions for responsive web design.
What Are PX and EM Units?
Pixels (px) are fixed units used to define exact dimensions in CSS. They do not scale automatically with font size changes.
EM is a relative CSS unit that is calculated based on the font size of its parent element. Unlike REM, EM values can change depending on where they are used in the layout.
This makes EM especially useful for component-based designs where spacing should scale with the component’s font size.
Why Convert PX to EM?
PX to EM conversion is commonly used when building reusable components and scalable UI elements.
- Allows spacing to scale with text size
- Improves flexibility in nested components
- Useful for buttons, cards, and form elements
- Helps maintain proportional spacing
- Reduces reliance on fixed dimensions
How to Use the PX to EM Calculator
Follow these steps to convert pixel values into EM units using our calculator:
- Enter the pixel (px) value you want to convert.
- Provide the font size of the parent element.
- The calculator instantly displays the EM value.
- Copy the result and apply it in your CSS.
PX to EM Conversion Formula
The formula for converting PX to EM is:
EM = PX ÷ Parent Font Size
The parent font size depends on the element where the EM value is applied.
PX to EM Conversion Examples
Below are some examples using a parent font size of 16px:
- 16px ÷ 16 = 1em
- 24px ÷ 16 = 1.5em
- 32px ÷ 16 = 2em
- 40px ÷ 16 = 2.5em
Common Use Cases for EM Units
EM units are particularly useful in component-based and modular CSS systems:
- Buttons that scale with text size
- Reusable UI components
- Nested layouts where spacing should adapt
- Form fields and labels
- Typography-based spacing systems
EM vs REM: Key Differences
EM units depend on the parent element’s font size, while REM units depend on the root font size.
EM is ideal for local scaling within components, whereas REM is better for global consistency across an entire layout.
Frequently Asked Questions (FAQs)
What font size is used for EM calculation?
EM is calculated using the font size of the parent element where the EM value is applied.
Can EM values change unexpectedly?
Yes. Because EM is relative to the parent element, deeply nested elements can scale if not managed carefully.
Is EM better than PX?
EM is more flexible and scalable, while PX provides fixed sizing. The best choice depends on your layout needs.
Can I mix EM and REM units?
Yes. Many projects use EM for component-level spacing and REM for global layout and typography.
Is EM supported by all browsers?
Yes. EM units are fully supported in all modern browsers.
Disclaimer: EM values depend on the font size of the parent element. Results may vary depending on nesting and inherited styles.