Open CSV Online

A CSV that Excel could not handle or has already damaged. Millions of rows open at once, the delimiter and encoding are detected for you, and codes with leading zeros stay codes.

Open your .csv Download for Windows

Free for personal use. No sign-up and no upload of the file anywhere. Windows version — 3.5 MB, no installation: details. Organizations: license.

Size does not matter

One pass builds an index of line starts, after which any row is available instantly. The file is never read into memory as a whole.

The delimiter is detected

Semicolon, comma, tab, pipe. If the automatic guess is wrong, change the delimiter with one click and the file is re-read.

Encodings without a BOM

Legacy code pages such as windows-1252, windows-1251 and cp866 are recognized from the content. You can also switch the encoding by hand, without re-saving the file.

Codes stay codes

00123, a ZIP code or a long account number is not turned into a number and does not lose its leading zeros — unlike what Excel does on open.

Your file never leaves your computer. Parsing happens in the browser, in a background thread. The page's security policy forbids sending data to third-party addresses — you can check this in the developer tools. After the first visit the app keeps working offline.

What is parsed correctly

A customer CSV in the browser: encoding and delimiter detected, account IDs and ZIP codes keep their leading zeros

quotes, escaped quotes and line breaks inside a field;
ragged rows: missing fields are shown empty, extra ones are moved into additional columns, and you are told about it;
numbers like 1 234,56 — with a space as the thousands separator and a decimal comma;
dates such as 15.01.2025 and 2025-01-15;
the header row is detected from the content: if the first row contains numbers, it is treated as data.

More: keeping leading zeros, encoding problems and choosing the delimiter.

Filters instead of formulas

Conditions that in Excel would need helper columns are written as one line:

UPPER(LAST_NAME) LIKE 'SMITH%' AND YEAR(ORDER_DATE) >= 2024 AND LEN(TRIM(ZIP)) <> 5

The filter applies to the whole file, not to the first thousand rows, and everything works on the rows that passed it: statistics, grouping and export are calculated for exactly those rows.

Export to the format you need

From a CSV you can export Excel (.xlsx with real dates and numbers), JSON, SQL with a ready CREATE TABLE, Markdown, HTML and even DBF — column types are inferred from the data, and field lengths are counted in bytes of the target encoding so that non-ASCII text is not truncated.

Working with very big files? See how to open a large CSV file. Need to tell two versions apart? See comparing two CSV files and finding duplicates.

FAQ

Excel says the file is too large. Will it open here?

Yes. Excel is limited to 1,048,576 rows; there is no such limit here. The file is read in parts, so the size is limited only by free disk space.

Why is everything in one column?

The delimiter was not detected. Open “File parsing” and choose the right one — the page shows the start of the file so you can see which it is.

Will leading zeros survive an export to Excel?

Yes: a column in which values like 00123 occur stays a text column, and it will be text in the .xlsx too.

Can I compare two CSV files?

Yes, by key columns: we show the rows that appeared, disappeared or changed, down to the individual field.

In depth

How to open a CSV fileWhat a CSV file is and how to open it: online as a table, in Excel column by column, without garbled characters or lost leading zeros. Nothing is uploaded.
Why Excel ruins codes in CSV filesWhy Excel turns 00123 into 123, long IDs into scientific notation and drops their last digits when opening a CSV — and the ways to keep codes as text.
A CSV with a million rows: what to open it withWhat to do when a CSV will not open in Excel because of its size: the 1,048,576-row limit and a comparison of Power Query, Python, DuckDB and browser viewers.
CSV encoding and the mysterious BOMWhy a UTF-8 CSV shows up as garbled text in Excel, what the BOM is, how it differs from windows-1252, and how to save a file that everyone can read.
CSV in one column in Excel: how to open it properlyWhy a CSV opens in a single column in Excel, how regional settings and the semicolon are involved, and four ways to get a proper table.
Compare two CSV files: what changed between exportsComparing two CSV exports by key: what was added, removed or changed, and in which field. Why line-by-line diff and VLOOKUP give results you cannot trust.
Duplicates in CSV: finding them and sorting them outFinding repeats in a CSV by one or several fields: grouping with counts, partial duplicates, whitespace and case differences, and what to do next.
Validate IBANs, emails, phone numbers and IDs in a tableCheck IBAN and card checksums, US SSN and EIN, EU VAT, ISBN, emails, phones and ZIP codes in CSV, Excel and DBF online. Bad rows are flagged; nothing is uploaded.
Link two tables: a master table and its detailLink two tables on a key and view them together: orders on top, their lines below. Move through the master rows and the detail table follows along.
Validate personal ID numbers in a table: SIN, NINO, PESEL, CPF and othersCheck SIN, NINO, DNI, PESEL, CPF, Aadhaar and other national ID numbers by checksum in CSV, Excel and DBF online. Nothing is uploaded.
Validate tax and company IDs in a table: EIN, VAT, NIP, CNPJ, SIRET, PANCheck EIN, VAT, NIP, CNPJ, SIRET, Partita IVA and PAN tax numbers by checksum in CSV, Excel and DBF online. Nothing is uploaded.