Split CSV File

Large exports cause small problems everywhere. An email attachment is too big, a web shop imports at most 5,000 products at a time, a CRM chokes on half a million rows, or each regional manager should only see their own region. Splitting the file into smaller parts solves all of these, and this tool does it in your browser.

Three ways to split

“Rows per file” cuts the table into pieces of a fixed size, for example 1,000 rows each, with the last part holding whatever is left. “Number of files” divides the rows as evenly as possible into the number of parts you choose; if the rows do not divide exactly, the first parts get one extra row. “One file per value” groups rows by a column, such as Region or Country, and writes each group to its own file.

The header comes along

When the first row is a header, every part starts with the same header row. Each file can therefore be imported or opened on its own without guessing which column is which. The row counts shown in the file list exclude the header, so 1,000 rows per file means 1,000 data rows.

File names you can work with

Parts made by size are numbered with leading zeros, such as “orders - part 01” to “orders - part 12”, so they sort correctly in every file manager. Parts made by value are named after that value, like “orders - North”, with characters that are not allowed in file names replaced. Rows with an empty value go into a file called “(blank)”.

Choosing a size

Check the limit of the system the files are going to. Many import tools state a maximum number of rows; email providers usually cap attachments around 20 to 25 MB. As a rough guide, a CSV with ten short columns takes about 100 bytes per row, so 100,000 rows are around 10 MB. Stay a little below any hard limit.

Formats

Download the parts as CSV, TSV or Excel. With Excel, each part becomes its own .xlsx file rather than one workbook with many sheets, because that is what most uploads expect. All parts come together in one .zip file.

Large files on your device

Everything runs in your browser, so the practical limit is your device’s memory. Files of a few hundred megabytes work on most computers; on a phone, stay under roughly 50 MB. Nothing is uploaded, which also makes splitting fast.

Values stay exact

Every cell is copied exactly as it is in the original, including leading zeros, long ID numbers and dates in any format. Splitting never reinterprets your data.

Splitting by value for sharing

When each recipient should only see their own data, splitting by a column is safer than filtering by hand and emailing the whole file by mistake. Pick the column that identifies the recipient, such as Region, Account manager or School, and check the file list: each file name shows the value, and the row counts show how much each person receives. Values are matched exactly, so “North” and “north” become separate files; clean such variations first with CSV Find and Replace.

Related tools

To put parts back together, use Merge CSV Files. For workbooks with one tab per group, Split Excel Sheets saves each sheet as a file. To pick a random subset instead of splitting everything, try Sample CSV Rows.