CSV to TSV Converter - TestMu AI (Formerly LambdaTest)

How to Convert CSV to TSV Programmatically (Python and DuckDB)

If you need to convert files inside a script or data pipeline instead of pasting them in by hand, both Python and DuckDB can turn CSV into TSV in a single command. The only real change is swapping the comma delimiter for a tab, so your columns line up on tab stops instead of commas.

Convert CSV to TSV in Python with Pandas

The pandas library reads a CSV into a DataFrame and writes it back out with a tab separator. Passing index=False stops pandas from adding an extra row-number column to the output.

import pandas as pd

# Read the CSV, then write it back out as tab-separated
df = pd.read_csv("input.csv")
df.to_csv("output.tsv", sep="\t", index=False)

Convert CSV to TSV with Python's Built-in csv Module

If you would rather avoid a dependency, the standard-library csv module handles it too. It reads the comma-delimited rows and re-writes them with a tab delimiter, correctly preserving any quoted fields.

import csv

with open("input.csv", newline="") as f_in, \
     open("output.tsv", "w", newline="") as f_out:
    reader = csv.reader(f_in)                  # default comma delimiter
    writer = csv.writer(f_out, delimiter="\t")
    for row in reader:
        writer.writerow(row)

Convert CSV to TSV using DuckDB

DuckDB can read and re-export a file in one SQL statement, which is handy for very large datasets. The COPY command below reads the CSV, keeps the HEADER row, and writes tab-separated output.

COPY (SELECT * FROM read_csv_auto('input.csv'))
TO 'output.tsv' (DELIMITER '\t', HEADER);

How Does the Converter Handle Commas, Quotes, and Newlines?

A safe CSV to TSV conversion is more than a find-and-replace of commas with tabs. Well-formed CSV follows the RFC 4180 standard, which lets a single field contain commas, double quotes, or even line breaks as long as that field is wrapped in double quotes. The converter parses those rules first, so your data structure stays intact.

• Fields with commas: A value like "Doe, John" is read as one field, not two. Because TSV uses tabs as the delimiter, the surrounding quotes are no longer needed and the comma is kept as ordinary text.
• Fields with quotes: RFC 4180 escapes a literal double quote by doubling it (""). The parser turns each doubled quote back into a single quote character in the output.
• Fields with newlines: A quoted field can span multiple lines. The converter treats it as a single cell, so a stray line break never splits one record into two rows.
• Fields that already contain a tab: Since a tab now marks the column boundary, any tab already inside your data is the one case to watch for - clean it before converting to avoid an unexpected extra column.

How to Convert CSV to TSV Online: Step by Step

Converting a file with this tool takes only a few seconds - no installs and no sign-up required:

• Paste your CSV data: Copy the contents of your comma-separated file - whether it comes from Excel, Google Sheets, or an app export such as Greenhouse or Kiln - and paste it into the Enter Value box above.
• Click Convert to TSV: Press the Convert to TSV button. The tool swaps every field delimiter for a tab while preserving your header row.
• Copy the TSV output: Your tab-separated result appears instantly in the Output box, ready to copy into a spreadsheet, a database import, or a saved .tsv file.

Supported Encodings and Header Preservation

Two questions come up whenever data moves between formats: does the header survive, and will special characters stay intact? Here is how this converter handles both.

• Header row is preserved: The first line of your CSV is treated like any other row - its comma delimiters become tabs, but the column names themselves are never dropped or reordered. Your TSV opens with the same header.
• UTF-8 encoding: The output is UTF-8, so accented letters, currency symbols, emoji, and non-English text (for example, CJK characters) carry over without turning into garbled characters or question marks.
• No data loss: Only the delimiter changes. Every value, in the same order, ends up in the TSV - which is why the file can be converted straight back with the TSV to CSV Converter.