Why Excel Struggles With Large CSV Files

Excel is the app most people reach for when a CSV lands on the desktop. For a 200-row budget, that is fine. For an export with a million orders, it is the wrong shape of program.

The hard limit

A worksheet maxes out at 1,048,576 rows and 16,384 columns. If your file is bigger, Excel truncates it and often does not make that obvious.

CSVUtility’s 1 GB benchmark file had 12.49 million rows, 11.9 times that worksheet cap, and still completed indexing, search, filter, sort, data-quality, and export. That comparison is to the editable Excel grid, not Power Query or the Data Model. Full numbers are on the benchmarks page.

Long before that cap, scrolling stutters, filters take minutes, and Save turns into a progress bar you do not trust.

The silent edits

CSV is text. Excel is a calculator. On open it will often:

• Drop leading zeros in IDs, ZIP codes, and account numbers
• Turn 2024-01-12 into a serial date
• Guess delimiters and encodings, then rewrite quoting on save
• Convert long numeric strings into scientific notation

You asked it to show a table. It tried to infer a spreadsheet.

Google Sheets has a 10 million cell ceiling, including CSV imports. The same 1 GB file held 99.9 million cells, almost 10 times that limit. Sheets also needs the file in the cloud and still coerces types.

How CSVUtility treats the same file

CSVUtility is a CSV editor, not a workbook. Cells stay text until you change them. Only the cells on screen are drawn. The file is read from disk as you go, so opening a multi-gigabyte CSV does not mean creating a string for every cell. See how to open a large CSV on Mac.

On save it writes what you edited. File → Export Copy… (⌘E) is the place to pick format without overwriting the original:

• Format: CSV (comma), TSV (tab), CSV (semicolon), or PSV (pipe)
• Rows: Entire file, Current filtered view, or Selected cells
• Line endings: LF (macOS / Unix) or CRLF (Windows)
• Encoding: UTF-8, UTF-8 with BOM, UTF-16, Windows-1252, or ISO Latin-1

Defaults for those controls live in Settings → Import & Export.

Before you overwrite a large file, Automatic previous versions (Settings → Large Files & Storage) can keep a copy. File → Reveal Previous Version in Finder jumps to that copy.

When Excel is still the right choice

Use Excel when you need pivot tables, charts, or .xlsx collaboration. Export a slice with Export Copy… set to Selected cells or Current filtered view, do the analysis, and keep the source in CSVUtility so the original text stays intact.

Use a CSV editor when the file is the product: a feed, a database dump, a migration, or a log you have to clean and send back.

Try it on the file that stalled Excel

Download CSVUtility (macOS 14 or later) and open the same CSV. If you only need a conversion or a quick check, the in-browser tools run locally with no upload.