About this tool

Em to Rem Converter

Convert ems to rems instantly. Free, bidirectional, and fully in-browser.

1 em equals 1 rems — enter any em value to convert it to rems instantly. This Em to Rem converter is a client-side tool: it applies a single multiplication (rem = em × 1) in your browser, updates the moment you type, and works in both directions — edit either field, or press swap, to convert rems back to ems. A reference table lists common em values already converted, and nothing you enter is sent to a server.

How to use Em to Rem Converter

1. 1

   Open Em to Rem Converter on AltFTool — it loads instantly in your browser.

2. 2

   Paste or upload your source content.

3. 3

   Choose the target format or conversion mode.

4. 4

   Copy or download the converted result.

Why use Em to Rem Converter

• Instant, both ways

  The result updates as you type, and the swap button flips the conversion to rem → em without reloading.

• Exact Typography math

  The conversion uses the precise factor (rem = em × 1), so the number matches a manual calculation to the decimal places you choose.

• Adjustable precision

  A slider sets 0–10 decimal places, and very small or very large results switch to scientific notation instead of rounding to zero.

• Private and free

  Everything runs locally in your browser — no upload, no account, no limit on conversions.

Common use cases

• Converting a em measurement to rems for a spec, listing, or report.
• Checking em↔rem figures while comparing products, datasets, or documentation.
• Learning the em-to-rem relationship from the worked formula and the common-value table.

Frequently asked questions