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What you get from this CSV → XLSX workflow
Built for the searches people actually run: turn exports into Excel-native workbooks with delimiter and encoding you control, optional frozen headers, smarter number and date typing, previews before download, and one-click merge when you need every CSV as its own sheet.
- Delimiter you can trust: Auto-detect from the first line or lock to comma, semicolon, tab, or pipe so columns land where Excel expects them.
- Encoding that fixes mojibake: UTF-8 for modern files; Windows-1252 or ISO-8859-1 when regional or legacy exports show wrong symbols.
- Frozen header row: Keep column labels visible while scrolling through long imports.
- Typed numbers and dates: Let Excel treat values as numbers and dates instead of text so sorting, SUM, and charts behave.
- Merge into one workbook: Stack many CSVs as separate sheets inside a single XLSX—great for monthly dumps or multi-region feeds.
- Named sheets: Set a worksheet title per file; merged mode derives names from filenames automatically.
- Live previews: Inspect parsed CSV (first 50 rows) and the output grid before you download.
- Privacy-first execution: Parsing and XLSX generation stay in-browser; skip the upload queue for sensitive rows.
Why export CSV to XLSX?
XLSX is the format coworkers, finance, and ops teams already use—typed cells, filters, pivot tables, and sharing without re-teaching delimiter quirks.
- Excel-native editing: Open directly in Microsoft Excel or compatible spreadsheet apps.
- Room for formulas next: Layer calculations, conditional formatting, and charts after the import lands cleanly.
How the conversion works
Your file is decoded with the encoding you pick, split on the delimiter you choose (or the auto guess), optional typing rules run, then SheetJS writes a standards-based XLSX you can download immediately.
- Load and configure: Bring in one or many CSVs, then set delimiter, encoding, sheet naming, header freeze, typing, and merge mode.
- Parse locally: The reader runs in your tab, builds tables, and shows CSV plus Excel previews so you can validate before saving.
- Download: Save individual XLSX files or the combined workbook. Flip an option anytime to regenerate output.
CSV import options explained
Each control changes how bytes become columns. Options apply across the batch; updating them reconverts finished files so you can iterate fast.
- Delimiter: Auto inspects the header line; manual mode is for files where detection might guess wrong.
- Encoding: UTF-8 is the modern default—switch to Windows-1252 or ISO-8859-1 when accents or currency symbols misread.
- First row as header: Locks row one under Excel’s freeze panes so stakeholders always see field names.
- Detect numbers and dates: Promotes string-like values into real Excel types when the pattern is unambiguous.
- Combine workbooks: Flattens many uploads into one downloadable XLSX with a sheet per source file.
- Sheet name: Single-file mode respects your label (sanitized, ≤31 chars). Merge mode prioritizes filenames.
Which encoding should I pick?
If characters look like random symbols, you’re almost always on the wrong decoder—try the next option below.
- UTF-8: Default for APIs, data warehouses, and most SaaS exports saved as Unicode.
- Windows-1252: Typical for Excel-on-Windows CSV saves in Western European locales.
- ISO-8859-1: Fallback for older Latin-1 pipelines when UTF-8 and Windows-1252 still look off.
Powered by client-side spreadsheet processing (SheetJS).
Frequently asked questions
How do I open CSV in Excel without wrong columns or garbled characters?
Match the delimiter to your file—Auto reads the first line, or choose comma, semicolon, tab, or pipe. If text looks corrupted, switch encoding between UTF-8, Windows-1252, and ISO-8859-1. Changing options reconverts files you already finished.
Can I set the Excel sheet name?
Use the sheet name field (for example "Data" or "Import"). Invalid characters are stripped and the name is capped at 31 characters. When merging, each CSV becomes a sheet named from its filename.
What does "First row as header" do?
It freezes the top row so headers stay visible while you scroll—ideal when row one holds column titles.
What does "Detect numbers and dates" do?
Values that look like numbers or parseable dates become Excel numbers and date serials for formulas and charts. Anything ambiguous stays text.
Can I merge several CSV files into one Excel file?
Enable "Combine into one workbook". Each CSV becomes its own sheet inside a single XLSX; use "Download combined XLSX" for the merged file.
Does my data leave my computer?
No. Conversion runs entirely in your browser; files are not uploaded to a server.
Can I batch convert many CSVs at once?
Yes. Add multiple files, download separate XLSX files, or merge them. Shared options apply to every file; tweak settings to reconvert completed items.