Convert CSV to Excel
Choose a CSV, Excel or JSON file; the encoding and separator are detected automatically, and accented letters and leading zeros are kept. Your file never leaves your device.
- CSV→ becomes XLSX
- Up to 25 MB
- No sign-up
- Encoding and separator auto-detected
55 CSV to Excel
- 01 Pick
- 02 Process
- 03 Download
Processed on your device · no upload
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Values only: the last calculated result of each formula is written; the formula itself, colours, formatting, merged cells and charts are not carried over.
- The work is done in this tab, on your device.
- Cells are kept as text; leading zeros and accented letters stay intact.
- No file is sent to our server; closing the tab clears everything.
First choose a CSV, Excel or JSON file
Stages
- Reading the file
- Converting the table
- Preparing the file
What's next?
Turn the table into a PDFXLSX→ becomes PDF- Your file stays on your device
- No upload to our server
- Free, no sign-up
Microsoft Excel and other product names are used only to describe file formats and belong to their owners; Dönüştür.net is not affiliated with these companies.
01
Why does a CSV file open incorrectly in Excel?
Order exports from online shops, bank statements and exports from accounting software very often arrive as CSV files. When you double-click one, Excel can show three familiar problems: each row is squeezed into a single column, letters such as “é” or “ü” turn into “é” or “ü”, and the leading zeros of ZIP/postal codes, phone numbers and customer IDs disappear, while long card or barcode numbers turn into 8.69E+12.
The causes are simple. Excel treats a UTF-8 file without a byte order mark (BOM) at the start as an old ANSI file, so accented letters break. Files exported from European Excel (German, Turkish, Spanish…) use a semicolon (;) as the separator and a decimal comma (1.234,56), which English Excel doesn't split into columns. And Excel turns anything that looks like a number into a number, dropping leading zeros along the way.
Dönüştür.net's tool detects the encoding (UTF-8, UTF-8 with BOM, UTF-16, Turkish ANSI Windows-1254 / ISO-8859-9) and the separator (, ; tab |) by itself, repairs garbled characters and creates a real Excel file (XLSX): header row bold and frozen, column widths adjusted, every cell exactly as in the file. In the other direction, it turns Excel into a clean CSV or into JSON. Everything happens in your browser; your file is not sent to a server.
02
Convert CSV to Excel in 3 steps
Choose your file: Choose a CSV, TSV, TXT, Excel (XLSX) or JSON file (up to 25 MB and 200,000 rows). The encoding, separator and header row are detected, and a preview of the first 50 rows appears straight away.
Check the preview: If the preview looks right, there's nothing to do. If the columns are shifted, choose the separator yourself; if letters look wrong, choose the encoding. If you want to calculate with amounts and dates in Excel, turn on “Convert numbers and dates”.
Download: Press “Convert”. You can open the XLSX file directly in Excel, LibreOffice or Google Sheets; a CSV output with the default settings opens in columns when you double-click it in English Excel.
03
Who uses it, and for what?
Online sellers: Opening order and product exports from your shop platform in Excel with proper columns; turning Excel into the CSV a platform asks for when you bulk-upload products.
Accountants and bookkeepers: Moving exports from accounting software and online banking into Excel without breaking amounts, whether they are written as 1,234.56 or 1.234,56.
Bank statements: Opening comma-separated UTF-8 transaction lists without everything piling up in one column; turning amounts into real numbers to add them up if you like.
Small businesses and offices: Sharing customer, stock and staff lists while phone numbers, ZIP/postal codes, IBANs and customer numbers stay exactly as they were typed.
Developers: Turning an Excel sheet into JSON (headers become keys) or pulling JSON from an API into Excel; nested fields open into columns such as “address.city”.
Files from other systems: Opening semicolon-separated exports from European Excel or old ANSI files from Turkish software; repairing letters such as “é” or “ü” in files that were once opened wrongly and saved that way.
04
Settings, limits and privacy
By default, no value changes: Every cell is written as text, exactly as it is in the file; leading zeros, IBANs, phone numbers and barcodes stay intact, and numbers with 12 or more digits don't turn into 8.69E+12.
Number and date conversion: If you want, amounts such as 1,234.56 or 1.234,56 become real numbers, and dates such as 29/09/2026, 29.09.2026 or 2026-09-29 become Excel dates (US-style 9/29/2026 too, when a value makes the order clear). A column is converted only if all of its values fit; columns with leading zeros, 12 or more digits, a leading “+” or a header such as ID, IBAN, phone, barcode, SKU or postal code stay text.
Encoding and garbled letters: UTF-8 (with or without BOM), UTF-16, Windows-1254 and ISO-8859-9 are recognised automatically. Letters garbled by a file that was once opened wrongly and saved, such as “é” or “ü”, are repaired to é and ü, and the number of repaired characters is shown.
Excel to CSV: The default output is what English Excel opens cleanly: comma, UTF-8 with BOM and 1,234.56. For European Excel choose semicolon, for software usually UTF-8 without BOM, and Windows-1254 for old Turkish programs; in files with several sheets, you choose the sheet.
What isn't carried over: Only values are transferred. The last calculated result of each formula is written; the formula itself, colours, formatting, merged cells, charts and images are not. Save old .xls files as .xlsx in Excel first.
Limits and privacy: Up to 25 MB and 200,000 rows; large files can take a few seconds. Your file isn't uploaded; the work happens in your browser and is cleared from memory when you close the tab.
05
Privacy and automatic deletion
This tool does not send your file to our server: all processing happens in your browser, on your device. The page is served with a security policy (Content-Security-Policy) that technically prevents the file's contents from being sent anywhere; no analytics or advertising scripts run on this page.
The result file is also created on your device and only you download it. It is cleared from the browser's memory when you close the tab or choose “New file”. Our server keeps no file name or content record of this processing.
06
Frequently Asked Questions
Why do characters look garbled in Excel?
The file was saved as UTF-8 but lacks the marker Excel looks for at the start (the BOM), so Excel reads it as an old ANSI file and “é” turns into “é”. Convert the file here to XLSX or to a CSV in UTF-8 with BOM and the letters display correctly. If the file was already opened wrongly and saved that way, the tool repairs the garbled letters too.
Why does my CSV file open in a single column in Excel?
Excel splits a CSV using the list separator of your region settings. English Excel expects a comma (,), but files from German, Turkish or Spanish Excel use a semicolon (;), so the whole row lands in one cell (and the reverse happens in European Excel). The tool detects the separator by itself and turns the file into an XLSX with proper columns; you can also get a CSV with the separator you need.
Why do leading zeros disappear, and how do I keep them?
When Excel opens a CSV, it treats values such as 01234 or 0151… as numbers and drops the leading zero; numbers with 12 or more digits (barcodes, card numbers) show up as 8.69E+12. This tool writes every cell as text by default, so ZIP/postal codes, phone numbers, IBANs and barcodes stay exactly as typed.
Should a CSV use a comma or a semicolon?
It depends on who opens it. English-language Excel and most software, databases and online platforms expect a comma (,). Excel in countries that use a decimal comma (Germany, France, Turkey and others) expects a semicolon (;). If you're not sure, look at a sample file from the place you'll upload to and use the same separator.
Can I calculate with amounts and dates in Excel?
Yes, if you turn on “Convert numbers and dates”: amounts such as 1,234.56 become numbers and dates such as 29/09/2026 or 2026-09-29 become Excel dates, so you can add them up and sort them. You can choose the decimal format (1,234.56 or 1.234,56) or leave it on automatic. Columns such as phone numbers, IDs and barcodes still stay text.
Can I convert Excel to JSON?
Yes. When you choose JSON as the output, each row becomes an object and the names in the header row become keys; numbers are written as numbers and dates as YYYY-MM-DD. In the other direction, when you choose a JSON array, nested fields open into columns such as “address.city” and arrays are written into the cell as JSON text.
What happens to formulas, colours and multiple sheets?
Only values are transferred. When you export Excel to CSV or JSON, the last calculated result of each formula is written; colours, formatting, charts and merged cells are not carried over. In a file with several sheets, you choose which sheet to convert.
Is my file uploaded to a server?
No. All the work happens in your browser, on your device; the page comes with a security policy that technically blocks it from connecting anywhere else. That makes it suitable for tables with personal data too, such as customer lists, bank transactions and order files.