CSV & Excel Tools
CSV encoding conversion, CSV to Excel, Excel to CSV, and more — handle CSV & Excel files right in the browser. Your files are never uploaded to a server, so your data stays safe.
CSV & Excel Tool List
CSV Encoding Converter
Fix CSV character encoding issues. Convert between Shift_JIS and UTF-8 to resolve garbled text in Excel.
CSV to Excel Converter
Convert CSV files to Excel (.xlsx) format. No character encoding issues, with auto column width.
CSV Viewer
View CSV files as readable tables in your browser. Auto-detects encoding with sort and filter support.
Excel to CSV Converter
Convert Excel files (.xlsx/.xls) to CSV or TSV. Choose sheets, encoding, and line endings.
TSV ⇔ CSV Converter
Switch between TSV and CSV formats with one click. Auto-detects encoding for seamless conversion.
🔒 sakutto tools run entirely in your browser by default
Your files are generally never uploaded to a server. A few tools require external communication due to CORS constraints or third-party APIs. View Privacy Policy
Free online tools for converting and viewing CSV and Excel files
The sakutto CSV & Excel category bundles every common spreadsheet utility: CSV encoding conversion, CSV-to-Excel and Excel-to-CSV conversion, CSV viewing, and TSV/CSV interconversion. Every tool is free, requires no sign-up, and runs entirely in your browser, so customer lists and accounting data stay on your device.
Fix CSV mojibake with encoding conversion (csv-encoding)
csv-encoding handles bidirectional conversion between Shift_JIS, UTF-8, and UTF-8 with BOM. Use it for CSVs that show garbled characters in Excel, files that need to become UTF-8 for system integration, and product imports for e-commerce backends.
Convert between CSV and Excel (csv-to-excel / excel-to-csv)
csv-to-excel turns a CSV into an .xlsx workbook, and excel-to-csv exports an Excel sheet as CSV. They are the bridge between data processing and downstream systems, with sheet selection and delimiter options where it matters.
Open CSVs directly in your browser (csv-viewer)
csv-viewer lets you open a CSV in tabular form without having Excel installed. It works on Mac, Windows, iPhone, and Android, so you can quickly inspect a CSV that just landed in your inbox even from a phone.
How to fix Shift_JIS / UTF-8 CSV mojibake with csv-encoding
"It looks garbled when I open it in Excel" or "the system rejects my CSV unless it is UTF-8" — encoding problems are everywhere in CSV work. csv-encoding solves them in seconds.
Upload the garbled CSV file
Open csv-encoding and drop the garbled CSV into the upload area. The tool auto-detects the source encoding (Shift_JIS, UTF-8, or UTF-8 with BOM), so you don't have to know which one it is.
Pick the output encoding and convert
Choose the encoding you want to output, then click convert. Pick Shift_JIS or UTF-8 with BOM if you want Excel to open it cleanly, or plain UTF-8 if you are feeding a web system. The result is generated in-browser and downloads instantly.
Convert between CSV and Excel (csv-to-excel / excel-to-csv)
Moving data between business systems, spreadsheets, and analytics tools constantly requires CSV/Excel round-trips. sakutto provides dedicated tools for each direction.
- Turn CSVs into easy-to-read Excel files (csv-to-excel)
- csv-to-excel converts CSVs into .xlsx workbooks. Encoding and delimiter are auto-detected, and the output is formatted so it opens cleanly in Excel — no more squashed columns or unreadable rows.
- Generate CSVs from Excel for system integration (excel-to-csv)
- excel-to-csv exports a chosen sheet from an Excel workbook as CSV. It supports multiple sheets, lets you pick the delimiter (comma, tab, semicolon) and encoding, and is ideal for backend imports, data warehouse pipelines, and Python preprocessing.
- Convert between TSV and CSV (tsv-csv-convert)
- tsv-csv-convert handles bidirectional conversion between tab-separated and comma-separated values. It is the right tool when you copy a TSV out of Notion or Google Sheets and need a CSV — or when you need to paste a CSV into a spreadsheet that expects TSV.
View CSVs in your browser without installing Excel
Often you just need to see what's inside a CSV that landed in your inbox or came out of a system — without firing up Excel. csv-viewer keeps the whole flow inside the browser.
- csv-viewer opens CSVs as tables in your browser
- csv-viewer lets PCs and phones without Excel display any CSV as a sortable table directly in the browser. It works on Mac, Windows, iPhone, and Android, with column resizing and search built in.
- No more mojibake when reviewing CSVs
- csv-viewer auto-detects encoding, so Shift_JIS and UTF-8 CSVs both display correctly without garbled characters. You no longer need to convert encoding before peeking at a file — the review step becomes nearly instant.
Why CSV and Excel files are safe to process entirely in your browser
Customer lists, sales data, member rosters — CSV/Excel files often contain confidential information, which is exactly why "never uploaded to a server" matters here.
- All CSV and Excel processing is client-side
- csv-encoding, csv-to-excel, excel-to-csv, csv-viewer, and tsv-csv-convert all process files entirely in your browser. CSV and Excel files are never transmitted to a server.
- Free, no sign-up, batch processing supported
- Every CSV/Excel tool is free with no sign-up. The Free plan supports batch processing for several files at a time, which is enough for most day-to-day workloads.
CSV & Excel — Frequently Asked Questions
Are sakutto's CSV & Excel tools really free? Do I need to sign up?
Yes, every CSV and Excel tool on sakutto — encoding conversion, CSV to Excel, Excel to CSV, CSV viewer, and TSV/CSV converter — is free and requires no sign-up. The Free plan supports batch processing for several files at a time, which covers most everyday workloads.
Are CSV files uploaded to a server? Are confidential records safe?
All CSV and Excel tools on sakutto run entirely client-side in your browser, so files are never transmitted to a server. That makes them safe for customer lists, sales data, and member rosters that contain personal information. They keep working even when you're offline.
How do I fix a CSV that shows garbled characters in Excel?
Use csv-encoding to convert the file to Shift_JIS or UTF-8 with BOM. Excel opens both encodings cleanly without garbled characters. If you instead need to feed the CSV into a web system, choose plain UTF-8 (without BOM).
Can I open a CSV without Excel installed?
Yes — csv-viewer lets PCs and smartphones without Excel display any CSV as a table in the browser. It works on Mac, Windows, iPhone, and Android, and auto-detects the encoding so the file shows up correctly without manual setup.
Can I convert between TSV (tab-separated) and CSV (comma-separated)?
Yes, tsv-csv-convert handles bidirectional conversion between TSV and CSV. Use it when you copy a TSV out of Notion or Google Sheets and need a CSV, or when you need to paste a CSV into a spreadsheet that expects TSV. Delimiter options are flexible.
CSV & Excel Articles
All articlesHow to Open CSV Files | Step-by-Step Guide for Windows, Mac & Mobile
Learn how to open CSV files on Windows, Mac, iPhone, and Android. Covers Excel, Google Sheets, browser-based tools, fixing garbled text, and changing your default CSV app.
Excel Shortcut Keys Cheat Sheet | Essential Keyboard Shortcuts for Windows & Mac
A curated cheat sheet of Excel keyboard shortcuts organized by category, with both Windows and Mac equivalents. Covers copy/paste, cell operations, formatting, formulas, sheet navigation, and more.
File Size Units Explained | KB, MB, GB, TB Conversion Chart
A quick-reference chart for file size units from bytes to terabytes. Includes conversion tables, real-world size examples by file type, email attachment limits, and the Mbps vs MB distinction.
How to Convert CSV to Excel | Complete Guide to Saving as XLSX
Learn how to convert CSV files to Excel (xlsx) format. Covers 5 methods for Windows and Mac, batch conversion, and how to avoid character encoding and formatting issues.
How to Fix CSV Character Encoding Issues | One-Click Encoding Converter
Fix garbled text in CSV files by converting character encoding. Learn why CSVs display incorrectly in Excel and how to convert between UTF-8 and Shift_JIS on Windows and Mac.
UTF-8 vs. Shift_JIS: Understanding CSV Character Encoding
Learn the differences between UTF-8 and Shift_JIS character encodings. Understand why CSV files get garbled, how to choose the right encoding, and how to convert between them.