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PX・REM/EM 換算器

PX to REM converter: convert px, rem and em based on root font size 16px for responsive and mobile styles, with one-click copy and offline.

使い方

数値とルートフォントサイズを入力し、方向を選ぶと結果と式が即表示。

Overview

PX to REM / EM Converter is a Developer tool. PX to REM converter: convert px, rem and em based on root font size 16px for responsive and mobile styles, with one-click copy and offline. It runs 100% in your browser with no upload, so you get instant results with privacy. Whether you need a quick answer or batch processing with precise control, you can enter, validate and export in seconds. The UI is responsive on mobile, tablet and desktop and supports one-click copy.

Use cases

  • Daily use of PX to REM / EM Converter: Enter a value and root font size, pick a direction, and get the result plus formula instantly. — enter and get instant results without manual lookup.
  • One-click copy keeps results ready to save, check or share with family and pros.
  • Use PX to REM / EM Converter offline or on poor network — all calculations stay local and private.
  • Format and validate JSON
  • Test regex with highlights

How to use

  1. 1 Enter a value and root font size, pick a direction, and get the result plus formula instantly..
  2. 2 Pick action and options
  3. 3 Fix highlighted errors
  4. 4 Copy or export

Highlights

  • Local & private: processing stays in your browser
  • Live validation with tolerant parsing
  • One-click copy and export for docs, code or sheets
  • Batch and offline support under poor network

Notes

  • Watch greedy vs lazy regex
  • Disable live validation for large files
  • Strict JSON disallows comments/trailing commas

FAQ

Offline?
Yes, parsing is local.
Why invalid?
Trailing commas, single quotes or BOM often cause it.
How is PX to REM / EM Converter different?
It runs locally with a focus on speed and privacy, plus tolerant parsing for “px em, responsive font” and one-click copy for reuse.
Can I use results in official reports?
Use it as a working draft and cross-check with authoritative sources; keep the exported log and parameters for traceability.
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すべての計算はブラウザ内で実行され、データはアップロードされません。