CSV Size Analyzer
Upload or paste a CSV file to see exactly what you're dealing with: raw file size in bytes, KB, and MB, row and column counts, the average, minimum, and maximum character length for every column, an estimated in-memory footprint if the file were parsed into JavaScript objects, and how many rows are exact duplicates.
Reviewed by Vincenzo Manto, Founder & Lead Developer · Last updated September 27, 2026
How it works
- 1
Paste your CSV text or upload a .csv file.
- 2
The tool parses it and computes size, shape, and column-level statistics instantly.
- 3
Review the summary cards for total size, row/column counts, and duplicates.
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Check the per-column table for average, minimum, and maximum field lengths.
Know your data before you process it
Before importing a CSV into a database, a spreadsheet, or a data pipeline, it helps to know its real shape: how many rows, how wide the columns are, and whether it's bloated with duplicate entries. This tool gives you that picture in seconds instead of writing a one-off script.
Spotting bloat and duplication early
Duplicate rows and unexpectedly long field values are common signs of a bad export or a failed deduplication step upstream. Surfacing the duplicate count and per-column length statistics up front makes it easy to catch these issues before they cause problems further down your workflow.
Frequently asked questions
How is the estimated in-memory footprint calculated?
It approximates what the data would cost in memory if parsed into an array of JavaScript objects: roughly 2 bytes per character for UTF-16 string storage, plus a fixed per-field overhead for the object structure itself. It's an estimate, not an exact V8 measurement.
How are duplicate rows detected?
A row is counted as a duplicate if every field in it exactly matches an earlier data row (the header row is never counted). Whitespace and casing differences are treated as different values.
Does file size include the header row?
Yes, the byte/KB/MB size reflects the entire raw text you provided, including the header. Row and column counts, however, describe the data rows and fields, with the header excluded from the row count.
Can this handle very large CSV files?
It can, but since everything runs in your browser, extremely large files (hundreds of MB) will be limited by your device's available memory and may take a moment to process.
Is my CSV data uploaded anywhere?
No. All parsing and analysis happen in JavaScript in your browser, and nothing is sent to a server.