To edit a big CSV file online, import it into a Datablist collection, check the column types, make your changes, and export a new CSV. You can search, filter, edit cells, and merge duplicates in the same workspace.
Keep the original file and validate the exported copy. With large files, a successful import matters as much as the edit: check the number of imported records and preserve identifiers such as postcodes or account IDs as text.
Spreadsheet tools have row, cell, and memory limits that can prevent a large CSV from opening. The number of columns and the length of each value also affect how much memory the file needs.
In this guide, you will learn:
- How to import, edit, and export a large CSV in Datablist
- How to work in smaller files when your dataset exceeds the import limit
View vs Edit CSV files
This guide focuses on editing rows and exporting a changed file. Datablist can also search and filter the imported data. If you only need to find a value, you may not need a full editing workflow.
A free alternative to big data tools is to use the Terminal on Linux and macOS. Check our guide: How to search in a big CSV file using Linux or macOS Terminal.
Edit large CSV files online with Datablist
Datablist is an online data editor. It opens CSV files directly in your browser without third-party software. Datablist works by using the database feature provided by modern web browsers (check our documentation to learn more).
The Free plan supports up to 1 million items per collection. Paid plans support larger imports; check the limit shown in the import assistant and compare the current plans before loading your file. Browser memory, available storage, and the size of individual values also affect how practical a large import will be.
Step 1: Create a collection and import your CSV file
Note
Datablist CSV editor requires signing up to open big CSV files. Please create an account before continuing.
To import your CSV file into Datablist, create an empty collection and use the Import CSV/Excel assistant to load your file.
Select the CSV columns you want to import and confirm the detected data types. Datablist reads the first lines of your file and detects the data type for each column. Data types are important for sorting and filtering your collection later on.
Check the preview data, and click Import to launch the import process.
Notes
Import time depends on your file, browser, and device. Keep the tab open and check the progress. If you stop an import before it finishes, check how many rows were imported before continuing.
Step 2: Edit your big CSV file online
During import, Datablist parses the CSV into collection items. Large local collections use browser storage, which persists across page reloads but can be lost if you clear site data. Keep your original CSV and export a copy after editing. Read how local storage and cloud synchronization differ. If Datablist reports that it cannot save in browser storage, follow the storage-error recovery steps before clearing site data.
With Datablist, you can filter your CSV file with one or several conditions and use "full-text" search.
💡 Search and filter performance depends on the collection and your device. Narrow the view before editing, then check whether your export should contain the filtered rows or the whole collection.
Edit items
Edit your items with a spreadsheet-like interface. Press Enter on a cell to edit its content. For datetime values, a calendar is available. And big texts are editable in a large textarea.
An item detail drawer opens when you click on the expand button on the left of your item line.
Merge duplicate items
Datablist comes with some advanced editing features to manage your data. One of them is the duplicate items finder.
The deduplication algorithm compares the values from one or many properties and lists all duplicate items. On the duplicates listing, you can merge all non-conflicting duplicate items automatically. A merging assistant is available to merge the remaining conflicting items. Read our guides to learn how to deduplicate a CSV file or how to merge duplicate rows from an Excel file.
If a column contains lists of emails, tags, or IDs, expand the values into separate rows before you deduplicate or export the file.
Merge items
Items merging is available directly in the data listing view. Select the items you want to merge and click Merge items.
All selected items are compared and the item with the most data is elected as the "Primary Item". Then, non-conflicting values from other items are set in the primary item empty properties. When confirming the merging, all but the primary item are deleted. The primary item is kept with the combined values.
Step 3: Export your edited CSV data
Once you have finished your modifications, you can keep your data on Datablist or export it into a CSV or Excel file.
Options are available to configure your export:
- Properties to export - Collection Properties can be hidden from the data listing. When at least one property is hidden, the exporter let you decide if the export must include all or only the visible properties.
- The export format - CSV or Excel.
- Column Delimiter - For CSV format, an option to select between "Comma" or "Semicolon" is available for the column delimiter.
Important
Excel cells have a 32,767-character limit, and each worksheet has a row limit (see Excel limits). I recommend CSV for collections that exceed an Excel worksheet's row limit.
Check the exported CSV
Before replacing the source file, reopen a copy of your export and check:
- The record count matches the scope you chose: all items, selected items, or filtered items.
- Identifiers still have their leading zeros and long values are intact.
- A few edited rows contain the expected changes, while unrelated rows are unchanged.
- The delimiter and column order suit the system receiving the file.
For example, if you filtered 2,000 contacts from a 200,000-row list to fix a company name, decide whether you need those 2,000 contacts or the complete updated list. Those are different exports.
For bigger CSV files
Split your CSV files and merge results
If your CSV exceeds the import limit for your plan, split it into files below that limit and use separate collections. Check the imported record count for every part so you do not mistake a partial import for the whole dataset. Edit each part, export it, then combine the results if needed.
Splitting changes the scope of your checks. A duplicate may appear in two different parts. If your goal is deduplication, account for duplicates across files rather than assuming each cleaned part makes the combined result unique.
To split a big CSV file, use Datablist's free CSV Splitter. It can split by row count, file size, column values, rules, or date ranges.
Important
To import your smaller CSV files into Datablist, they must have a header row. It's important you configure your CSV splitter to copy the header row into each split file.
Follow the tutorial above to edit your small CSV files.
Then use another online tool to merge back all your CSV files into one. ExtendsClass offers a good tool to merge CSV online.
For Mac and Linux users
The last option for Mac and Linux users is Visidata.
Visidata is a free tool and uses the terminal to show and interact with your CSV file. It can be scary for non-technical users... But if you want to impress yourself, give it a go!
FAQ
What is Google Sheets row limit?
Google's current file limits list up to 20 million cells or 100 MB for spreadsheets created in or converted to Google Sheets. A cell limit is not a fixed row limit: the available rows depend on the number of columns and other sheets in the workbook.
For example, 20 columns across 500,000 data rows already use about 10 million cells before allowing for headers or other sheets. Passing the cell limit does not guarantee that every calculation or edit will be fast on your device.
What is Airtable row limit?
Airtable limits records across all tables in a base. Its current workspace limits list 1,000 records on Free, 50,000 on Team, and 125,000 on Business. Enterprise Scale limits differ. Check your plan before choosing it for a large CSV.
What is Microsoft Excel row limit?
According to Microsoft Support, an Excel worksheet supports 1,048,576 rows, including any header row.
Also, each cell can't contain more than 32,767 characters.
Should I use Apple Numbers for a large CSV?
Check your Numbers version and test a copy of the file before using it for a large edit. An import can exceed an application's limits or be impractical to edit even when it opens. Compare the imported count with the source file before saving changes.
Do you have sample CSV files to test Datablist?
Sure! Visit our sample CSV Files page to download CSV files with data up to 2 million records.