Will my leading zeros survive?

Yes, if you mark the column as text — and DataTray asks rather than guessing. This is the single commonest thing lost when a CSV is converted by opening it in Excel and saving it again.

What if the CSV has more than a million rows?

It converts. Excel's sheet limit is 1,048,576 rows, so a larger file will need splitting before Excel can open the result — Data Converter can do that in the same pass.

Is there a file-size limit?

No. There is no upload, so there is nothing to cap. Web converters limit you because they are paying for the bandwidth.

Free converter

CSVExcel

CSV to Excel Converter

Turn a CSV into a real .xlsx workbook without opening it in Excel first — which is where the damage usually happens. Postcodes keep their leading zeros, long IDs stay whole instead of becoming scientific notation, and a file too big for Excel to open still converts.

Windows 10/11 (x64) · Free · No account

Drop in your files — Converted workbooks land in DataTray's output folder, dated. Your CSV is untouched.

Why convert

Why not just open it in Excel?

Because opening a CSV in Excel is a conversion, and it is a lossy one. Excel guesses each column's type as it reads, and its guesses are wrong in the same three ways every time: a postcode like 02134 loses its leading zero, an 18-digit ID becomes 1.23457E+17, and anything that looks vaguely like a date becomes one. Converting the file directly lets you state the types instead of hoping.

Sending a database export to somebody who only works in Excel.
Converting a CSV that has more rows than Excel will open.
Keeping postcodes, account numbers and product codes exactly as they were written.
Turning a folder of CSVs into workbooks in one run rather than one at a time.

How it works

Convert CSV to Excel in a few clicks

1
Drop the CSV in
DataTray detects the delimiter, quoting and encoding, and shows you what it found so you can correct it before anything is read.
2
Check the column types
Anything that should stay text — postcodes, IDs, phone numbers — you mark as text, and it comes out the other side unchanged.
3
Convert
Out comes an .xlsx. Drop in a folder instead of a file and the whole folder converts in one job.

The details

CSV to Excel, at a glance

Input: CSV, TSV, PSV, or fixed-width, at any size
Output: .xlsx — a real workbook, not a renamed CSV
Row limit: None on the way in; Excel's own 1,048,576 applies when you open the result
Runs: Entirely on your PC. Nothing is uploaded

Questions