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csv ↔ tsv · delimiter swap · rfc 4180 · live

Swap between CSV and TSV

Switch delimiter from comma to tab and back. Quoted fields with embedded commas, tabs or newlines survive intact thanks to RFC 4180 parsing.

CSV ↔ TSV
Input
44 B
3 lines
Output
44 B
3 lines
Status
ready
live
Ratio
1.00×
out/in
input · csv
output · tsv
name	age	city
Alice	30	Boston
Bob	25	Seattle
Quick Start

How delimiter swap works

RFC 4180 parsing reads each cell with the source delimiter, then re-quotes any cell that contains the target delimiter, a quote, or a newline. The schema (headers) is preserved exactly.

  1. 01

    Pick a direction

    Toggle CSV → TSV or TSV → CSV.

    Parsing is strict-but-tolerant — comments and trailing commas are accepted on input where the source format historically permits them; output stays canonical.

    modestricttolerantliveparse
    dir · sourceset · live
    CSV → TSV
    loaded · parsedtarget · ready
  2. 02

    Paste data

    Quoted fields with embedded delimiters are kept exactly.

    Conversion preserves type information where the target supports it (numbers stay numeric, booleans stay boolean) so the destination parser never has to re-coerce.

    inputtype-preservinglosslesslivememoised
    in · optionsrows · live
    name,age
"Doe, J",30
    options applied · liveround-trip
  3. 03

    Requote as needed

    If a value would clash with the new delimiter, it is wrapped in double quotes.

    Re-encoding is idempotent: running output back through the same converter produces the same bytes, which keeps round-trips git-friendly.

    quoteidempotentround-tripdiff-cleandeterministic
    guard · converteddelim · ready
    "Doe, J"	30
    converted · livediff-clean
  4. 04

    Copy or download

    Drop into Excel, Google Sheets, or pipe to another command-line tool.

    Copy writes via navigator.clipboard.writeText; downloads use the target’s native MIME so editors apply the right syntax highlighting on open.

    exportclipboardtarget MIMEblobclient-side
    ✓ · copiedready · done
    ✓ Copied
    shipped · ready to shipsuccess
Pro tips

Converting between formats, safely

Pick the strictest source format

Lossy formats hide bugs. Choose JSON or YAML as your source-of-truth, convert downstream as needed.

Round-trip in CI

If your converter is idempotent, your CI can verify A → B → A equals the original. Catches subtle data loss.

Numbers vs strings differ

YAML/TOML have a number type; CSV doesn’t. Quote IDs in CSV to keep leading-zero values intact.

Watch character encoding

Source format may be Latin-1 / Windows-1252; target should be UTF-8. Convert encoding before structure.

Preserve comments where you can

YAML and TOML support comments. Don’t silently drop them — they often encode intent.

Schema-aware beats blind

Use a schema to guide conversion. Field types, required-ness, and defaults survive better with structure.

Related toolsCSV to JSONCSV to YAMLCSV to XMLCSV to SQLCSV to HTMLYAML to CSV
Use Cases

When to switch delimiters

Data exchange, command-line tools, locale fixes.

European CSV

Some locales reserve commas for decimals — TSV avoids the clash. Type information survives: numbers stay numeric, booleans stay boolean, strings stay strings. The destination parser doesn't have to re-coerce, which avoids the "'true' becomes "true"" bug class.

i18n

Excel paste

Excel pastes tab-separated data straight into cells. Run output back through the inverse converter to verify idempotent round-trips in CI. A → B → A should produce byte-identical input — if it doesn't, you've found data loss.

type-preserving

Unix pipelines

cut, awk and friends prefer tab-separated input. Comments and metadata survive where the target format supports them (YAML, TOML, HCL). The tool doesn't silently drop intent-encoded annotations, which keeps your config self-documenting.

schema-aware

Data lakes

Some warehouses expect tab-separated bulk loads. Pair with a schema (JSON Schema, OpenAPI, Zod, Pydantic) to catch shape drift on either side. Catch breaking changes at conversion time rather than at runtime in production.

lossless

BI imports

Reporting tools sometimes accept TSV but not CSV. Output respects target-format conventions: quoting in CSV, indent in YAML, brackets in JSON. Existing parsers don't need patches, and the result drops into legacy pipelines unchanged.

diff-clean

Open data

Mirror a CSV dataset as TSV for downstream tooling. Encoding-aware: handles UTF-8 vs UTF-16 vs Latin-1 / Windows-1252 transparently. The character-set surprise that breaks "works on my machine" doesn't apply here.

spec-grade
FAQ

Frequently asked questions

Yes — RFC 4180 parsing handles quoted fields with embedded commas, tabs and double-quotes (doubled to escape).
Both \r\n and \n are accepted on input; the output uses \n by default.
Values stay as-is — no rounding, no padding. The tool only swaps delimiters.
The first row is always treated as the header row. Add a placeholder header row if your data has none.
No. Parsing runs locally in your browser.
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