What CSS units does this converter support?

It supports all major CSS units: px (pixels), rem (root em), em (parent em), vh (viewport height), vw (viewport width), % (percentage), pt (points), cm (centimeters), and mm (millimeters).

Why do rem and em conversions need a base font size?

rem is relative to the root element's font size (usually 16px by default), and em is relative to the parent element's font size. Setting the correct base values gives you accurate pixel equivalents for your specific design context.

How are viewport units (vh/vw) calculated?

1vh = 1% of the viewport height, and 1vw = 1% of the viewport width. You can set your target viewport dimensions in the context settings to get accurate px conversions for responsive design.

When should I use rem instead of px?

Use rem for font sizes and spacing so your layout scales with the user's browser font settings, improving accessibility. px is fine for borders, shadows, or elements that shouldn't scale.

Yes, completely free. All conversions happen in your browser instantly — no server calls needed.

Convertisseur d'unités CSS

Convertir les unités CSS : px, rem, em, vh, vw, %, pt, cm, mm. Ajustez la taille de police et le viewport pour des résultats précis.

Valeur

Unité source

Paramètres de contexte

Taille de police de base (rem base)

Taille de police parent (em base)

Hauteur du viewport (vh base)

Largeur du viewport (vw base)

Conversions

rem

2.0833

1.5625

100.00

12.000

0.4233

4.2333

Les unités relatives (rem, em, vh, vw, %) dépendent du contexte. Ajustez les paramètres ci-dessus pour des résultats précis.

Comment utiliser

Convertir les unités CSS : px, rem, em, vh, vw, %, pt, cm, mm. Ajustez la taille de police et le viewport pour des résultats précis.

1Enter a numeric value in the 'Value' field.
2Select the source unit (e.g., px) from the 'From Unit' dropdown.
3All equivalent values in other CSS units appear instantly.
4Expand 'Context Settings' to set your base font size and viewport dimensions for accurate rem/em/vh/vw conversions.
5Click 'Copy' next to any result to copy it to your clipboard.

Fonctionnalités

Converts between px, rem, em, vh, vw, %, pt, cm, mm
Adjustable base font size, parent font size, and viewport dimensions
Instant real-time conversion as you type
One-click copy for each converted value
No server needed — all calculations run in your browser

Questions fréquentes

En savoir plus

CSS Units Explained: px, rem, em, vh, vw and When to Use Each