Design specs, browser defaults, and legacy CSS rarely agree on font units. A font size converter helps you move between px, rem, em, pt, and percent without doing mental math or second-guessing your base size.
What Is the Font Size Converter?
Font Size Converter is one of the tools in WebdevToolbox’s Font & Unicode category. Convert font sizes between px, rem, em, pt, and percent, with a quick reference table that updates from the values you enter. It runs entirely in your browser — no server uploads, no accounts, no waiting.
How to Use It
- Open the tool at /tools/font-size-converter.
- Enter the font size you have and choose its current unit, such as px or rem.
- Adjust the base font size if you need calculations that match your project or browser default.
- Use the live conversion results and reference table to copy the unit values you need.
Key Features
- Multi-unit conversion — switch between px, rem, em, pt, and percent from one input.
- Adjustable base size — calculate rem and em values against the root size your project actually uses.
- Quick reference table — compare several equivalent sizes at a glance instead of converting one by one.
- Helpful for CSS cleanup — standardize typography tokens when a codebase mixes legacy and modern units.
- 100% client-side — all calculations happen in your browser with no uploads or waiting.
When to Use the Font Size Converter
- Design handoff — convert pixel-based mockups into rem values for implementation.
- Refactoring typography — replace inconsistent font units in an older stylesheet.
- Accessibility tuning — compare relative units before changing base type scales.
Try It Now
Open Font Size Converter directly from anywhere on the site using ⌘K and typing the tool name. No login required — everything runs offline-capable in your browser.
Part of the Font & Unicode collection on WebdevToolbox — free, browser-based developer tools with no login required.