DevToolsLab

CSV Cleaner

Clean Β· UTF-8 ↔ Shift-JIS

Clean CSV by removing duplicates, empty rows and stray spaces. Convert between UTF-8 and Shift-JIS.

5 β†’ 3 rows (2 removed)
Input CSV
Cleaned CSV

Preview

First 50 rows
nameagecity
η”°δΈ­30東京
佐藀25倧ι˜ͺ

Files are read locally β€” nothing is uploaded to any server.

What is a CSV Cleaner?

A CSV cleaner removes the typical noise found in CSV exports: duplicate rows, fully empty rows, and stray whitespace around values. DevTools Lab's CSV Cleaner adds something specific to the Japanese ecosystem: smooth conversion between UTF-8 and Shift-JIS encodings, plus automatic mojibake (ζ–‡ε­—εŒ–γ‘) detection. Open a file from your machine, clean it, and download the result β€” all without uploading anything.

Features

  • Remove exact-duplicate rows
  • Remove completely empty rows
  • Trim leading and trailing whitespace from every cell
  • Open files in UTF-8, Shift-JIS, EUC-JP β€” encoding auto-detected
  • Download as UTF-8 (with BOM) or Shift-JIS
  • Live preview of the first 50 rows in a table

How to use

  1. Click "Open file" and pick a CSV from your computer (encoding is auto-detected), or paste CSV directly.
  2. Toggle the cleaning options you want (duplicates / empty rows / trim).
  3. Inspect the preview table on the right.
  4. Click Download UTF-8 or Download Shift-JIS to save the cleaned file.

Frequently Asked Questions

Is my CSV file uploaded anywhere?

β–Ύ

No. Files are read with the browser's File API and processed locally. Nothing leaves your device.

What is Shift-JIS and why convert to it?

β–Ύ

Shift-JIS is a legacy Japanese character encoding still required by some accounting systems, government portals and Excel for Windows (Japanese edition). This tool converts UTF-8 ↔ Shift-JIS losslessly when characters are representable.

What is mojibake (ζ–‡ε­—εŒ–γ‘)?

β–Ύ

Mojibake is garbled text caused by reading bytes with the wrong encoding (for example, opening a Shift-JIS file as UTF-8). The tool auto-detects the source encoding to avoid this.

Does it handle quoted fields with commas inside?

β–Ύ

Yes. The parser follows RFC 4180 β€” quoted fields, escaped quotes ("") and embedded newlines are all handled correctly.

Can I process Excel (.xlsx) files?

β–Ύ

Not directly. Export from Excel as CSV first (File β†’ Save As β†’ CSV UTF-8 or CSV).

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Canonical: https://devformatlab.com/en/csv-cleaner