Font Size Converter
Convert font sizes between px, em, rem, pt, vw, and percent with live preview.
Live Preview
The quick brown fox jumps over the lazy dog. 0123456789
How to Use This Tool
- Enter your value into the Font Size Converter input field at the top of the page.
- Pick the source unit and the target unit, and the Font Size Converter will convert in real time as you type.
- Copy the converted value or swap the units to convert in the opposite direction.
Common Use Cases
- Data migration: Engineers convert between formats when moving data between systems with incompatible representations.
- Educational verification: Students check homework answers by converting between standard units or notations.
- Cross-team collaboration: Teams using different conventions exchange data via a common intermediate format produced by the Font Size Converter.
Frequently Asked Questions
What precision does the Font Size Converter preserve?
Numeric conversions use IEEE 754 double-precision (15-17 significant decimal digits). Lossless integer conversions remain exact up to 2^53. For exact decimal arithmetic on very large or very small values, use a server-side BigDecimal or arbitrary-precision library.
What's the supported input range?
The converter handles the full range allowed by the source format's specification. Values outside that range (e.g., negative durations, out-of-spec characters) are rejected with an error rather than silently truncated. Check the input format docs for exact limits.
Can I convert in both directions?
Yes. The converter is bidirectional: switch the source and target fields to reverse the conversion. Round-trip conversions are exact for lossless format pairs and approximate (with documented precision) for lossy ones.