CSV to Excel Converter
Create a safe XLSX with encoding detection, typed columns, protected IDs and an optional audit sheet.
This tool runs entirely in your browser. Your data is never uploaded, never stored, and never leaves your device.
Turns an uploaded or pasted CSV, TSV or delimited text file into a typed .xlsx workbook while protecting leading zeros, long identifiers and formula-like cells, with a preview and optional audit sheet that records every safety fallback.
How to use it
- 1Upload a .csv, .tsv or .txt file up to 20 MiB, or paste text, then analyse it; encoding and comma, semicolon, tab or pipe separator are detected but remain manually overrideable.
- 2Confirm the warnings and six-row preview, including detected blank rows, inconsistent widths, quote issues and column profiles.
- 3Keep each column's inferred type or force Exact text, Number, Date YYYY-MM-DD or Boolean; unsafe or invalid conversions remain text and are counted.
- 4Choose whether to include Import Audit, create converted.xlsx, and verify its Data sheet plus the audit counts before using it downstream.
Example
- Input
- customer_id,signup_date,active,note 000184,2026-09-20,true,"Prefers email" 9007199254740993,2026-09-21,false,=2+2
- Output
- converted.xlsx with Data and Import Audit sheets; 000184, 9007199254740993 and =2+2 are literal strings, the dates are Excel dates and active is Boolean
Auto-detection selects comma with high confidence and the audit records one protected leading zero, one protected long number, one neutralised formula-like value and zero conversion fallbacks. The audit stores counts and chosen types, not the source values.
What happens to your data
Parsing, profiling and workbook creation happen locally; no table is uploaded. UTF-8, UTF-8 BOM, UTF-16 LE/BE and Windows-1252 are handled, but ambiguous bytes or separators still require the preview. The import is capped at 200,000 rows and 2,000 columns, drops fully empty rows, pads short rows, and stores formula-like input as explicit XLSX text rather than executable formulas. Type inference is conservative, not a substitute for checking financial, scientific or locale-specific data.
Last updated September 2026
Turn a CSV, TSV, or delimited text export into a real Excel workbook without silently changing IDs, dates, or spreadsheet-like text. Upload a local file or paste data, then review the separator, encoding, column types, and warnings before downloading the XLSX. The CSV encoding detector can identify UTF-8, UTF-16, or Windows-1252 and still lets you override its choice.
Conversion happens in your browser. Toolvore does not upload the source data, and the optional Import Audit sheet records conversion decisions and safety counts without copying source values.
How it works
The converter detects comma, semicolon, tab, or pipe delimiters and can decode UTF-8, Windows-1252, UTF-16LE, and UTF-16BE text. Quoted delimiters, escaped quotes, and line breaks inside quoted fields are parsed as records rather than split blindly.
Each column can stay as exact text or be converted to number, YYYY-MM-DD date, or boolean. Identifier-like columns, leading zeros, numbers with more than 15 significant digits, and values that could be interpreted as spreadsheet formulas are protected as text. This blocks CSV formula injection without deleting the original characters. A value that does not safely match its selected type falls back to text and is counted in the audit.
The browser limit is 20 MiB, 200,000 rows, and 2,000 columns. Fully blank rows are removed; inconsistent row widths, duplicate or blank headers, low-confidence delimiter detection, and conversion fallbacks are shown before export.
Common use cases
- Open semicolon-, tab-, or pipe-delimited exports in Excel
- Preserve account numbers, postal codes, SKUs, and other leading-zero identifiers
- Convert legacy Windows-1252 or UTF-16 exports
- Create a typed workbook with an optional import audit trail
- Review malformed rows before sharing a spreadsheet
Frequently asked questions
Will leading zeros or long identification numbers survive the conversion?＋
Yes. Identifier-like columns, leading-zero values, and numbers with more than 15 significant digits are kept as exact text so Excel does not shorten or reformat them.
How does the converter handle spreadsheet formulas in CSV cells?＋
Values beginning with formula-like characters are written as literal text rather than executable formulas. The audit reports how many cells received that protection.
Which delimiters and encodings can it read?＋
It can auto-detect comma, semicolon, tab, or pipe delimiters. Encoding choices include automatic detection, UTF-8, Windows-1252, UTF-16LE, and UTF-16BE.
Can I control number, date, boolean, and text conversion?＋
Yes. Review or override the inferred type for every column. Dates are converted only from the unambiguous YYYY-MM-DD form; unsafe mismatches remain text and are counted.
What is stored in the Import Audit sheet?＋
It records the chosen separator, dimensions, safety counts, and type fallbacks. It does not duplicate any source values.
Does CSV data leave my browser?＋
No. Parsing and workbook generation run locally in the browser. The current limits are 20 MiB, 200,000 rows, and 2,000 columns.
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