Convert CSV to Excel
Open your CSV in Excel without the silent data corruption — no leading zeros stripped, no dates mangled, no account numbers turned into scientific notation.
For anyone who's been burned by Excel auto-formatting their CSV data. Free online — works in your browser.
How It Works
Upload Your CSV
Bank export, accounting report, or any CSV/TSV file. Comma, semicolon, tab, or pipe delimiters all detected automatically.
Data Types Preserved
Dates stay as dates, text stays as text, numbers with leading zeros keep their zeros. No silent auto-formatting by Excel.
Download XLSX
Formatted spreadsheet that opens in Excel, Google Sheets, LibreOffice, or Apple Numbers with all data intact.
What Happens When You Double-Click a CSV in Excel
Excel's auto-format engine silently changes your data the moment you open a CSV. These changes are invisible and irreversible once you save.
| Your CSV Data | Excel Shows | Our XLSX Shows |
|---|---|---|
| 007823 | 7823 | 007823 |
| 4532015112830366 | 4.53202E+15 | 4532015112830366 |
| 1-15 | 15-Jan | 1-15 |
| 10/12/2025 | 12/10/2025 * | 10/12/2025 |
| Café André | Café André | Café André |
* Excel swaps day/month based on your system locale — silently, with no warning.
What is CSV?
Comma-Separated Values
Plain text with values separated by commas, semicolons, tabs, or pipes. No data types — everything is a string. When Excel opens a CSV directly, it guesses data types and often guesses wrong, silently destroying your data.
What is XLSX?
Microsoft Excel Open XML Spreadsheet
A real spreadsheet with typed cells — text stays text, numbers stay numbers, dates are proper Excel dates. Formulas, filters, pivot tables, and charts work immediately. Opens in Excel, Google Sheets, LibreOffice, and Numbers.
Why This Tool
Leading Zeros Preserved
Account numbers (007823), ZIP codes (00501), check numbers (000142), and reference IDs keep their leading zeros — Excel would strip them on a raw CSV open.
No Scientific Notation
Credit card numbers, UPCs, and long IDs stay as full numbers. Excel auto-converts anything over 11 digits to scientific notation (4.53E+15) — we prevent that.
Dates Stay Exactly As-Is
Text like "1-15", "10-12", or "3/4" won't become January 15th, October 12th, or March 4th. Dates are formatted correctly only when they're actual dates.
Any Delimiter Detected
Comma, semicolon, tab, or pipe — auto-detected from your file. European bank CSVs use semicolons because commas are decimal separators. No manual delimiter selection needed.
UTF-8 Encoding Handled
Characters like €, £, ₹, ñ, ü, Ø, and CJK text come through correctly. No garbled ö or â€" replacement characters in your spreadsheet.
Clean Column Headers
First row detected as headers and formatted as a proper header row in Excel. No duplicate headers, no blank first rows, no merged cells.
When to Use This
Bank Statement Review
Open your bank's CSV export in Excel for sorting, filtering, and spot-checking transactions before importing into accounting software.
Accounting Data Prep
Bookkeepers and CPAs cleaning up CSV exports from multiple banks and payment processors before uploading to QuickBooks, Xero, or Sage.
Data Analysis & Reporting
Analysts building pivot tables, charts, and VLOOKUP formulas from CSV data sources — CRM exports, sales reports, transaction logs.
Where Your XLSX Works
Spreadsheet Apps
- Microsoft Excel (2007+)
- Google Sheets
- LibreOffice Calc
- Apple Numbers
Accounting Software
- QuickBooks (Excel import)
- Xero (upload via bank feed)
- Sage (spreadsheet import)
- Zoho Books
Analysis & Reporting
- Pivot tables & charts
- VLOOKUP / INDEX-MATCH
- Power BI (Excel source)
- Tableau (Excel connector)
Why Opening CSV in Excel Breaks Your Data
Leading zeros stripped from account numbers, ZIP codes, and check numbers
Excel treats any numeric-looking value as a number and drops leading zeros. Account 007823 becomes 7823, ZIP 00501 becomes 501. Our converter formats these cells as text in the XLSX, preserving every character.
Long numbers turned into scientific notation (4.53E+15)
Excel limits numeric precision to 15 digits. Credit card numbers, UPCs, and reference IDs beyond 11 digits are silently converted. The last digits become zeros. We store these as text to preserve full precision.
All data lands in column A — delimiter not recognized
Your CSV uses semicolons (European standard), tabs, or pipes instead of commas. Excel only auto-splits on commas in some locales. We detect the actual delimiter and split columns correctly.
Special characters garbled — ö instead of ö, â€" instead of —
Excel defaults to your system encoding (often Windows-1252), not UTF-8. Non-ASCII characters — accented letters, currency symbols, CJK text — get mangled. Our XLSX output uses UTF-8 encoding throughout.
Excel silently swaps day and month in dates
A date like 10/12/2025 could be October 12 or December 10 depending on your Excel locale. Excel picks one interpretation and changes the data permanently. We preserve dates exactly as they appear in your CSV.
Frequently Asked Questions
Why not just double-click the CSV to open it in Excel?
Double-clicking triggers Excel's auto-format engine: leading zeros are stripped (00123→123), long numbers become scientific notation (4532015112830366→4.53E+15), and text like "1-15" is silently converted to January 15th. Our converter preserves every value exactly as it appears in the CSV.
My CSV has semicolons instead of commas — will it work?
Yes. We auto-detect the delimiter — comma, semicolon, tab, or pipe. European bank exports often use semicolons because commas are used as decimal separators (1.234,56 vs 1,234.56).
Will my bank's account numbers and check numbers keep their leading zeros?
Yes. Account numbers like 007823 stay as 007823, not 7823. ZIP codes, reference numbers, and any text with leading zeros are preserved as text in the Excel output.
Can I open the XLSX file in Google Sheets?
Yes. Google Sheets opens XLSX files natively. Upload to Google Drive and open, or use File > Import in Google Sheets.
My CSV has special characters (€, £, ñ, ü) that turn into garbled text in Excel. Does this fix that?
Yes. We handle UTF-8 encoding correctly. Characters like €, £, ₹, ñ, ü, and Chinese/Japanese/Arabic text are preserved in the Excel output.
Does it add formulas or formatting to the spreadsheet?
No. The output is a clean data spreadsheet with proper column headers and data types. You add your own formulas, formatting, and pivot tables after.
Is there a file size limit?
No practical limit for typical CSV files. Bank statements with thousands of transactions convert in seconds.
Can I use this for non-financial CSVs?
Yes. Any CSV file works — CRM exports, survey data, log files, e-commerce reports. It's not limited to financial data.
Is my data secure?
Encrypted in transit via TLS, processed in memory, never stored. Your CSV data is deleted immediately after conversion.
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