How to use
Drop an Excel (.xlsx), CSV or TSV file, or click “Choose files”. CSV encodings (UTF-8, Shift_JIS, …) are detected automatically.
For workbooks with several sheets, pick the sheet to clean.
Tick the fixes you need under “What to clean” and choose a date format. The result updates as you change options.
Review highlighted cells and counts in the “Cleaned” view, or switch to “Original” to compare.
Choose the format (Excel / CSV) and encoding, then download.
What it does
12 fixes in one pass
Trim and collapse spaces, remove invisible characters and in-cell line breaks, half-width letters and digits, full-width katakana, unify hyphens in numbers, convert numbers and dates, and remove empty rows, empty columns and duplicate rows — only the ones you pick.
Understands Japanese business data
Parses Japanese eras (Meiji to Reiwa, including “R6.4.1”), “2024年4月1日”, full-width digits and amounts like “1,234円”, “￥500”, “▲500” or “(500)”. Codes with a leading zero, such as postal codes or employee IDs, stay as text.
See exactly what changed
Changed cells are highlighted, with per-fix counts and the number of removed rows and columns. Switch to the original view to check nothing unexpected changed before saving.
Header row protected
When the first row is treated as a header, it only gets whitespace and invisible-character fixes — no width, number or date conversion.
Saves files Excel opens cleanly
Save as Excel (.xlsx) or as CSV in UTF-8 with BOM, Shift_JIS, EUC-JP or UTF-16. If some characters cannot be represented in Shift_JIS, they are listed so you can switch to UTF-8.
Use cases
- Normalise inconsistent spacing and character widths in a customer list before lookups or matching
- Turn “1,234”, “¥500” or “▲500” exported from a business system into real numbers
- Unify a date column mixing Japanese eras, “2024.4.1” and “2024年4月1日”
- Strip zero-width spaces and empty rows left over from copy-and-paste
- Clean a Shift_JIS CSV and save it so it opens correctly in Excel
Supported formats
Input
Output
Capability matrix
| Feature | Support | Notes |
|---|---|---|
| Remove spaces, invisible characters, in-cell line breaks | Supported | — |
| Half-width letters/digits, full-width katakana | Supported | — |
| Unify numbers and dates (incl. Japanese eras) | Supported | Leading-zero codes stay text |
| Remove empty rows, empty columns, duplicate rows | Supported | — |
| Highlight changed cells with counts | Supported | — |
| Automatic CSV encoding detection | Supported | Shift_JIS / UTF-8 / EUC-JP / UTF-16 |
| Clean all sheets at once | Partial | One sheet at a time |
| Keep formatting, formulas, merged cells | Not supported | Formulas are exported as their values |
| Legacy Excel (.xls) | Not supported | Re-save as .xlsx in Excel first |
Limits & notes
- Up to 100 MB and 3 million cells per file. Large files may take a few seconds to clean.
- Saved files contain cell values only. Formatting (colours, borders), formulas, merged cells and data validation are not carried over.
- Duplicate removal only targets rows where every column matches. To find or merge duplicates by specific columns, use “Excel Deduplicate”.
- Name variants (e.g. “Inc.” vs “Incorporated”) are not merged.
Privacy & safety
Reading, cleaning and building the download all happen in your browser. Your data is never sent to or stored on a server.
FAQ
How do I convert full-width letters and digits to half-width in Excel?
Can I convert Japanese era dates to the Western calendar?
Will leading zeros in postal codes or IDs disappear?
Will a Shift_JIS CSV be garbled?
Is my data uploaded?
Related tools
Excel Compare
Load an old and a new Excel or CSV file to see added, removed and changed rows, with every changed cell shown as “old → new”. Save the result as a colour-coded Excel report or CSV.
Excel Deduplicate
Find duplicate rows in an Excel or CSV file by the columns you choose, ignoring the variations you choose, then remove them or merge each group into one row. Review every group, change which row survives, and save as Excel or CSV.
Excel Merge
Combine sheets from several Excel or CSV files: stack their rows into one table, or keep them as separate sheets in one workbook. Columns are aligned by header name automatically.
CSV Encoding Fix
Convert CSV files that show garbled text in Excel to UTF-8 with BOM or Shift_JIS, with automatic encoding detection. Mojibake that was already saved, such as “日本語”, can usually be restored too.
CSV Studio
Open CSV files that are slow or garbled in Excel and view, search and edit them right away in your browser. Combine, split and save as CSV (UTF-8 with BOM, Shift_JIS), Excel or JSON on one screen.
CSV, JSON, XML & Excel Converter
Convert between CSV, TSV, JSON, JSON Lines, XML and Excel (.xlsx) by pasting or opening a file. Values stay as text by default, so zero-padded postal codes, phone numbers and long IDs are never changed. Everything runs in your browser; your data is not uploaded.
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