PX to REM Converter

Convert between pixels and rem units. Adjust base font size for your project.

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rem
PixelsREMPT (print)

Free PX to REM Calculator

The Toolts PX to REM Converter helps web developers translate pixel values to rem units and vice versa. REM (root em) units are relative to the root element's font size, making them essential for building responsive, accessible websites. The converter includes a quick reference table showing common pixel sizes and their rem equivalents.

Why Use REM Instead of Pixels?

Pixels are absolute units that do not scale when users change their browser's default font size. REM units are relative to the root font size (typically 16px), so they automatically scale with user preferences. This is critical for accessibility — users who set larger default fonts (due to low vision or preference) will see your layout scale proportionally when you use rem units.

How the Conversion Works

The formula is simple: rem = px ÷ base font size. With the default base of 16px, 24px equals 1.5rem (24 ÷ 16 = 1.5). If your project uses a different base (like 10px for easier math), adjust the base font size field and all conversions update instantly.

Frequently Asked Questions

All major browsers set the default root font size to 16px. This means 1rem = 16px unless you change the font-size on the html element. Some developers set html { font-size: 62.5% } to make 1rem = 10px for easier calculations.
REM is relative to the root (html) element's font size and is consistent throughout the page. EM is relative to the parent element's font size, which can compound when nested. REM is generally preferred for layout and spacing because it is predictable.