CSS Unit Converter - px/rem/em/pt/vw Converter

1. How to use

1. Enter a value (e.g. 24) and pick its unit.
2. Set the root font size (html font-size, 16px default) — it drives px↔rem conversion; set the design viewport width when vw results are needed.
3. Pick the target unit for an instant result; multiple targets render as a comparison table simultaneously.

2. Two checks before converting

• rem is relative to the root element, em to the parent element — the same px value can differ in the two contexts, so confirm the target inherits which.
• vw/vh are viewport-relative, not fixed — results correspond to your configured base width; the browser is the source of truth.
• pt is a print unit (1pt = 1/72 inch), largely replaced by px on screens; only print styles genuinely need it.
• Mobile rem workflows commonly use 375/390px designs — do not convert mobile values against 1920.

3. The complete design-to-code pipeline

In real projects px → rem is just step one: the px value typically divides by the root size into a rem factor, then lands in CSS variables or a Tailwind spacing scale. Converters guarantee numeric correctness; the unit strategy is decided upfront — global rem responsiveness (font-size via media queries or clamp) or Tailwind px natively. Verify ratios with number-base-advanced afterwards so factor-of-16 math does not slip.