Stays local
CSV never leaves your browser. Nothing is uploaded.
No signup. Free. Paste or open a file.
Fix cells in a table, then download in the encoding you need.
CSV never leaves your browser. Nothing is uploaded.
Click a cell and fix it — lighter than wrestling Excel.
Save as UTF-8, UTF-8 BOM, or Shift-JIS for Excel.
Paste text or choose a CSV file.
Press “Show table” and edit cells in place.
Pick an encoding and save. Done.
My CSV is a free browser tool for editing awkward CSV files as a table—no Excel required.
Paste text or
open a file, then edit cells directly in “Show table”.
Download as UTF-8, UTF-8 with BOM, or Shift-JIS to reduce mojibake in Excel.
No signup, no login,
completely free.
Your CSV never uploads to a server; everything stays on your device.
Even files with personal data can be
edited and downloaded locally.
CSV stands for Comma-Separated Values. It is a simple text format for tabular data. When people search “what is CSV,” the practical answer is: a spreadsheet-like table written as plain text, usually with commas between columns. It shows up everywhere—Excel exports, database dumps, business system imports, and everyday data hand-offs.
CSV is not a programming language. It is closer to a shared habit for writing tables: one row per record, fields separated by a delimiter (often a comma). Humans can open it in a text editor; programs can parse it easily. The trade-off is that for a long time there was no single strict standard, so quotes, newlines, and character encodings still cause friction in the real world.
Comma-delimited text has been used for data exchange since early computing. Spreadsheets and mainframes needed a lightweight way to move rosters and sales tables between systems—lighter than tagged formats.
Microsoft Excel made CSV a business default. But Excel’s interpretation of encodings and delimiters varies by locale, which is why mojibake, Shift-JIS vs UTF-8, and UTF-8 BOM issues are so familiar—especially in Japanese workflows.
On the standards side, IETF RFC 4180 (Common Format and MIME Type for Comma-Separated Values) is the document most teams cite. It describes quoting rules for commas and newlines inside fields. Think of it as a common understanding for interoperability rather than a full schema language.
Typical points:
"Missing quotes, BOM surprises in Excel, and leading zeros dropping out are classic “broken CSV” symptoms. That is why browser CSV editors, encoding conversion, and quick visual checks are everyday tools.
Business data exchange is the main job: accounting, inventory, customer lists, attendance, ecommerce catalogs—anywhere two systems need to pass a table. Even when APIs speak JSON, humans often edit a CSV in between.
Analytics and ML pipelines love CSV. pandas, R, and BI tools treat it as a first-class input. Large logs frequently land as CSV or TSV before deeper processing.
Spreadsheet workflows matter too: round-trips with Excel or Google Sheets, email attachments, and public dataset distribution.
TSV uses tabs and can be kinder to free-text that contains commas. Excel’s .xlsx keeps formatting and multiple sheets but is heavier for code. JSON handles nesting well but is awkward for bulk cell editing. Use CSV for tables, JSON for hierarchies.
Fixing encoding, tweaking a few cells, and avoiding uploads of sensitive files are common needs. My CSV lets you paste or open a file, edit in a grid, and download as UTF-8 / UTF-8 (BOM) / Shift-JIS—free, no signup, and processing stays on your device.