Convert CSV to Excel — Typed Numbers, Real Dates, Clean Headers

Opening a CSV in Excel is easy. Opening a CSV in Excel **without losing your data** is not. Leading zeros vanish from IDs, long numeric strings get mangled into scientific notation, dates get re-interpreted by whatever regional setting your machine happens to use, and accented characters turn into mojibake unless the file has a UTF-8 BOM. Our CSV to Excel converter side-steps all of that by parsing the CSV correctly and writing a real XLSX workbook with typed cells — so when Excel opens it, every number is a number, every date is a date, and every header is a header.

The conversion runs entirely in your browser using the SheetJS engine. Your CSV never leaves your device — safe for sensitive financial, HR, customer or accounting data. The parser is RFC 4180 compliant: quoted fields, escaped quotes, embedded commas and multi-line cells all work the way the spec says they should. Delimiter detection is automatic (comma, semicolon, tab, pipe) and overridable when you need to be explicit.

On the output side you get a properly typed XLSX workbook. Numbers are stored as numbers (no more "Number stored as text" warnings), booleans as booleans, and ISO-format dates (`2024-05-20`) as real Excel date cells with a `yyyy-mm-dd` number format — so you can sort, filter, pivot and chart them straight away. Column widths are sized to the longest value in each column, the header row is bolded, and the top row is frozen so it stays visible while you scroll. You can also pick the legacy XLS (BIFF8) format for tools and macros that don't accept modern XLSX.

This tool is built for analysts converting exports from databases, BI tools or APIs into shareable workbooks; finance teams turning bank or accounting CSVs into clean Excel reports; e-commerce operators preparing product feeds for vendors who insist on XLSX; and developers shipping spreadsheet downloads alongside any web app.