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Unicode stays clean
UTF-8 with or without BOM, Windows-1252, ISO-8859-1 — common encodings are detected automatically. The output XLSX locks encoding to UTF-8 in OOXML, so accents, emoji, and CJK characters survive in every Excel version.
Auto-detects comma, semicolon, and tab delimiters. Preserves accented characters, emoji, and CJK. Protects SKUs like "01-05" from Excel's notorious date auto-conversion. Direct in the browser via SheetJS — no upload, no account.
Drop your CSV — get an .xlsx that opens cleanly in any Excel version.
or click to browse — .csv, .tsv, .txt
Fixes the two biggest pain points of opening CSVs in Excel.
UTF-8 with or without BOM, Windows-1252, ISO-8859-1 — common encodings are detected automatically. The output XLSX locks encoding to UTF-8 in OOXML, so accents, emoji, and CJK characters survive in every Excel version.
Comma, semicolon, tab, pipe — the tool counts column matches in the first rows for each candidate and picks the most consistent one. The detected delimiter shows in the preview before you convert.
Excel loves to turn "01-05" into "January 5" or "03-2024" into a date. When generating the XLSX, we mark ambiguous values as text cells, so SKUs, ZIP codes with leading zeros, and hex IDs stay intact.
Customer lists, revenue reports, employee data, payroll exports — the conversion happens via SheetJS in your browser. No upload, no server, no cloud. Privacy by design.
The first 8 rows with the detected delimiter are displayed up front. You see immediately whether columns are split correctly — before opening the result and discovering something is off.
No "5 files per day" cap like the classic online converters. Convert 100 Salesforce exports back-to-back — your browser CPU does the work, not our server.
Three steps. Zero encoding pain.
Drag-and-drop or file dialog. Accepts .csv, .tsv, .txt.
Tool shows columns and detected delimiter. If something looks off, re-save the CSV in a text editor first.
Click Convert. The file opens in Excel, LibreOffice, Numbers, or Google Sheets with zero reformatting.
Where CSV-to-Excel is most often needed in US/global business workflows.
CRM exports come as comma-separated UTF-8 CSVs. Names with accents (José, Müller, François) break in default Excel. Our converter passes them through cleanly so account managers can filter and pivot without a bandage script.
Accounting platforms export transaction lists and customer reports as CSV. With customer names from any country, the Unicode-safe round-trip matters for clean books and audit-ready Excel files.
Order exports, product listings, customer data — all comma-CSVs in UTF-8. English Excel handles them OK; international Excel mangles accented names. XLSX output sidesteps the entire codepage issue.
Marketing exports as CSV land in Excel for further pivots. Campaign names with "&" and special characters can break — XLSX export from the tool avoids every encoding and delimiter trap.
All export contact lists as UTF-8 CSVs. When cleaning and filtering in Excel, encoding must be right or first names with accents become unusable for personalized sends.
Statistical software often outputs CSV of result tables. Sharing those with non-technical stakeholders typically means XLSX. Browser conversion saves the round-trip through an installed Office suite.
Classic encoding issue: Excel opens UTF-8 CSVs without a BOM as Windows-1252 by default — the bytes for accented characters get misinterpreted. Our converter writes XLSX directly, where encoding is locked to UTF-8 in the XML spec — Unicode characters remain correct regardless of Excel version.
Yes — the tool auto-detects by analyzing the first rows. International tools (Shopify, Salesforce, GitHub) use comma. European Excel and some legacy ERP systems use semicolon. Tab and pipe are also detected. You don't need to configure anything.
When opening a CSV directly, yes — Excel aggressively interprets text as dates, which destroys product SKUs like "01-05", ZIP codes with leading zeros, or hex IDs. Our converter passes values as text cells when they're not unambiguously numeric, so the original string is preserved.
Yes. Salesforce and HubSpot export as comma-CSV in UTF-8. QuickBooks varies. All three sometimes ship CSVs that Excel mangles on open. Through our converter you get a clean XLSX that opens consistently in any Excel version.
Up to roughly 200,000 rows works smoothly in the browser. For very large files (1M+ rows) browser memory may get tight. Note: the XLSX format itself caps at 1,048,576 rows per sheet — that's a format limit, not ours.
CSV → Excel produces a workbook with a single sheet named 'Sheet1'. If you want to bundle several CSVs into one workbook with multiple sheets, convert them individually and combine in Excel afterward.
No. Conversion runs in your browser via SheetJS (xlsx 0.18.5). There is no server roundtrip — your CSV stays on your device. You can even load this page offline once and it keeps working.
Yes. SheetJS writes standard XLSX per the OOXML spec. The output opens in Excel 2007+, LibreOffice Calc, OnlyOffice, WPS Office, Apple Numbers, and Google Sheets without reformatting.
Working with data means working with CSVs. And working with CSVs in Excel often means painful surprises: accented characters break, columns end up in a single cell because the delimiter wasn't recognized, or Excel transforms "01-05" into "January 5" on its own. Our free online converter solves all three by producing a clean XLSX directly — Excel opens that without any guesswork.
Excel (both Windows and Mac, every version through Microsoft 365) opens a .csv in two steps: first it guesses the encoding — and this is where it goes off the rails. Without a UTF-8 BOM at the file start, Excel assumes Windows-1252 (Mac OS Roman on macOS). If the file is actually UTF-8, multi-byte sequences for accents become gibberish like "José" or "Müller". Second, Excel guesses the delimiter from regional settings — which is semicolon in much of Europe. A US-comma CSV opened in European Excel ends up as "one cell per row".
We read the CSV with modern JavaScript encoding detection (BOM detection, UTF-8 sequence validation, Windows-1252 fallback). For the delimiter we count columns per row for each candidate — comma, semicolon, tab, pipe — and pick the one with the most consistent column count. The result is written as XLSX, not CSV — and XLSX has its encoding locked to UTF-8 in OOXML. There's no room for Excel interpretation magic anymore.
Excel's automatic date detection is infamous: values like "01-05", "MAR1", "2-3", "1e10" get converted to dates or scientific notation, and the original value is lost. Genomics researchers have even published papers on Excel-mangled gene names. Our converter writes ambiguous values as text cells in the XLSX — Excel respects the text type and doesn't auto-convert.
CSV exports from CRMs, payroll systems, or e-commerce platforms often contain personally identifiable information: names, addresses, purchase histories, employee records. Uploading those to an unknown cloud converter is risky under GDPR (data processor relationship, possibly third-country transfer) and HIPAA (PHI in the wrong hands). BrowserCrunch sidesteps all of it — the file never leaves your browser. You can even load this page offline and it still works.
The generated .xlsx files follow the OOXML standard and open cleanly in Microsoft Excel 2007 and newer (Windows and Mac), LibreOffice Calc, Apple Numbers, Google Sheets (via upload), OnlyOffice, WPS Office, OpenOffice (with caveats), pandas (Python via openpyxl), R (readxl). Recipients don't need Microsoft Office.
Need the other direction? Our Excel-to-CSV converter for DB and API imports. For developers: CSV to JSON and JSON to CSV. For shareable reports: CSV as PDF table.