How is this different from CSV Dimensions Finder?

CSV Dimensions Finder reports row count, column count, and raw byte size only. CSV Size Analyzer adds two things it doesn't: a real measured gzip-compressed byte size, and automatic delimiter detection, on top of the same row/column/raw-size numbers.

How is this different from CSV Analyzer?

CSV Analyzer inspects your data's shape and content, per-column inferred types and unique-value counts. CSV Size Analyzer doesn't look at column types at all, it's purely about size, compression, and delimiter, the two tools answer different questions about the same CSV.

Is the gzip-compressed size an estimate?

No. The tool actually runs your CSV text through the browser's native CompressionStream("gzip") API and measures the real resulting byte count, the same number you'd get from actually gzipping the file.

How does delimiter detection work?

The tool tries comma, semicolon, tab, and pipe as candidate delimiters, parses the input with each, and picks whichever produces the most rows with a column count matching the header row, since the correct delimiter is the one that yields a consistent, rectangular grid.

CSV Size Analyzer - Raw Size, Gzip Size & Delimiter Detection

Overview

Introduction

Before you compress, split, or ship a CSV somewhere, it helps to know exactly how big it really is, both raw and gzip-compressed, and what delimiter it actually uses.

CSV Size Analyzer answers all of that from one paste: raw bytes, real gzip bytes, detected delimiter, row count, and column count.

What Is CSV Size Analyzer?

A single-pass CSV metrics tool that reports raw byte size, actual gzip-compressed byte size, the best-guess delimiter, row count, and column count.

Unlike a size estimate, the gzip figure comes from genuinely compressing the input with the browser's native CompressionStream API, so the number is real.

How CSV Size Analyzer Works

Delimiter detection tries comma, semicolon, tab, and pipe as candidates, parses the raw text with each via the shared CSV grid parser, and scores each by how many rows share the header row's column count, the delimiter that yields the most structurally consistent grid wins.

Raw size comes from TextEncoder-encoding the input to UTF-8 bytes and counting them; gzip size comes from piping those same bytes through CompressionStream("gzip") and measuring the compressed output; row and column counts come from parsing the input with the detected delimiter.

When To Use CSV Size Analyzer

Use this before deciding whether a CSV is worth compressing, or how many rows-per-chunk to use when splitting it.

It's also useful when you've received a CSV with an unclear or unlabeled delimiter and want a quick, evidence-based guess rather than eyeballing it.

Often used alongside CSV Dimensions Finder and CSV Analyzer.

Features

Advantages

Reports a genuinely measured gzip size, not a rough compression-ratio guess.
Delimiter detection is scored against real parse consistency, not just "does a comma appear anywhere."
Gives five useful metrics from a single paste, no separate tools needed for size vs. shape.

Limitations

Delimiter detection can be wrong on very small or unusually formatted CSVs where multiple delimiters happen to produce equally consistent grids.
Gzip size reflects this exact input as one file; splitting it into chunks (each with its own header and gzip overhead) will not shrink proportionally.

Examples

Analyzing a semicolon-delimited CSV

Input

id;name;score
1;Ada;95
2;Grace;72

Output

Delimiter: semicolon ( ; ), Rows: 3, Columns: 3, Raw size: 30 bytes, Gzip size: (real measured bytes)

Every candidate delimiter is tried, but only semicolon produces three rows that all share the header's 3-column count, so it's selected.

Best Practices & Notes

Best Practices

Check the detected delimiter before running other CSV tools on the same input, if it's wrong, most parsing tools in this category accept an explicit delimiter override.
Compare raw vs. gzip size to judge whether compressing this particular CSV is worth the trouble.
Re-run after editing a CSV in CSV Editor to see how your changes affected size and shape.

Developer Notes

analyzeCsvSize() detects the delimiter by parsing the input once per candidate in [",", ";", "\t", "|"] via parseCsvGrid, scoring each by how many resulting rows match the header row's column count (ties broken by preferring more columns), then re-parses once with the winning delimiter for the final row/column counts; gzip size comes from the same CompressionStream("gzip")-via-ReadableStream/Response pipeline used in csv-compressor.ts, just reporting arrayBuffer().byteLength instead of returning the bytes themselves.

CSV Size Analyzer Use Cases

Deciding whether a CSV is worth gzip-compressing before storing or sending it
Detecting an unlabeled or ambiguous CSV's delimiter before running it through other CSV tools
Getting a quick row/column/size snapshot of a CSV without opening it in a spreadsheet program

Common Mistakes

Assuming the reported gzip size applies if you later split the CSV into multiple files, each chunk carries its own gzip overhead and repeated header.
Trusting delimiter detection blindly on a one- or two-row CSV, very small inputs give the scoring less to work with.

Tips

If the detected delimiter looks wrong, check for a CSV with only one column, single-column data can't distinguish between delimiter candidates well.
Use CSV Compressor right after this if the gzip size shown here looks worth it.

CSV Size Analyzer