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PX to REM / VW Converter

Convert CSS units with a configurable base font size.

Free · No upload100% localInstant results

Coming soon

PX to REM / VW Converter is being built and will ship in the next release. It will run 100% in your browser like every other StackPulse utility. The documentation below explains what it does and how it works.

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Why convert PX to REM (or VW)?

REM units are the foundation of accessible, scalable typography and spacing. Because REM is relative to the root font size — 16 pixels by default in most browsers — switching values from REM to font-size on the <html> element scales the entire design. That keeps zoomed interfaces, larger accessibility fonts and responsive layouts consistent without a cascade of hard-coded pixel updates.

Converting individual values by hand, however, is exactly the kind of repetitive maths that introduces rounding drift. A PX to REM converter does the division for you against your chosen base font size (default 16px), producing clean, rounded REM values that match the CSS conventions of your project. The same tool converts pixels to viewport-width (VW) units when you are building fluid layouts that scale to the browser window instead of the root font.

The conversion runs locally in your browser, so there is no delay, no sign-up and no risk of your design tokens ending up on a foreign server. Paste a batch of pixel values, choose a base, and copy the converted declarations straight into your stylesheet.

Common use cases

Convert pixel-based design specs from Figma or Zeplin into accessible REM values
Rebuild a fixed-pixel codebase into a scalable, user-font-respecting design system
Compute VW values for fluid typography, grid gaps and full-bleed hero sections
Normalise spacing tokens across a team that mixes px and em units
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How to convert PX to REM or VW

  1. Enter one or more pixel values — comma or newline separated — into the input field.
  2. Set the base font size (16px by default) or leave it untouched for standard browsers.
  3. Choose REM or VW as the target unit, optionally with a precise decimal precision.
  4. Press Convert or Ctrl / ⌘ + Enter to compute every value instantly.
  5. Copy the resulting CSS values or the generated rem/vw declaration block.

Test cases

Input · 16px, 24px, 32px with a 16px base

1rem, 1.5rem, 2rem — tidy multiples of a 16px root font size.

Input · 100px as a VW value on a 1440px viewport

6.94vw — the pixel share of the design viewport width.

Frequently asked questions

Why does the base font size matter?

1rem always equals the root font size. If your <html> uses font-size: 14px, then 1rem is 14px. Supplying the correct base keeps your converted values accurate for your specific project.

Should I always use REM instead of PX?

For most typography and spacing, REM is preferred because it respects user font-size preferences and makes scaling trivial. PX is still appropriate for borders, shadows and fine lines where fixed dimensions are intentional.

Is this conversion done locally?

Yes. All arithmetic happens in your browser, so your design tokens and viewport assumptions are never transmitted.