How to open a CSV file that is too large for Excel
What to do when Excel says a CSV did not load completely.
Excel shows a warning that the file did not load completely, or it opens a CSV and the bottom rows are simply missing. You have hit Excel's row limit. The data is all still in the file; Excel just cannot show it.
The limits
| Program | Limit |
|---|---|
| Excel | 1,048,576 rows and 16,384 columns per sheet |
| Google Sheets | 10 million cells per spreadsheet, so fewer rows for wide tables |
| Apple Numbers | 1,000,000 rows per table |
Long before those limits, large files make spreadsheets slow. A few hundred thousand rows with many columns can already be painful to scroll, sort or filter.
Option 1: split the file into parts
The simplest fix. The split CSV tool cuts the file into parts with a set number of rows each, and copies the header row to the top of every part, so each one opens and works on its own. For Excel, 250,000 to 500,000 rows per part stays comfortably fast. Rows are never cut in half, even if they contain line breaks inside quoted text.
Option 2: keep only the columns you need
Many exports have dozens of columns and you need three. Removing the rest shrinks the file dramatically and often brings it under Excel's comfort zone. Extract columns keeps the columns you name, in the order you list them.
Option 3: import with Power Query
Excel's Data, From Text/CSV option loads the file through Power Query, which can filter rows before they reach the sheet, or load the data into the Data Model, which is not bound by the sheet's row limit. That is the right route if you need pivot tables across the full data set.
Option 4: use a tool made for big data
For millions of rows analysed regularly, a database or a data tool is a better home than a spreadsheet: a SQL database, Python with pandas, or a dedicated CSV viewer. For a one-off look, splitting is faster than learning a new tool.
Putting parts back together
Once you have cleaned or filtered the parts, merge CSV joins them into one file again, keeping a single header row.
Why do it in the browser
Large CSVs are usually exports of customers, orders or transactions. The tools linked here process the file in your browser's memory and never upload it. Files of a few hundred megabytes are fine on a laptop; on a phone, very large files may run out of memory.