Add Calculated Columns, Group By and Extract Text in a CSV Online
Do the everyday spreadsheet formulas without a spreadsheet: calculate, group, extract and clean in a few clicks.
Data Transformation now includes seven more steps. A calculated column adds, subtracts, multiplies or divides a column by a number or another column, or gives a percentage. Round numbers works on any columns.
Extract part of text pulls the first number, an email, a URL or digits into a new column, or uses your own pattern. Pad with zeros makes fixed-width IDs such as 00042. Clean text collapses spaces, removes accents and hidden characters, or keeps only letters or digits.
Group and summarize counts rows, or sums, averages or finds the smallest or largest value, per group. Keep first or last rows trims a long file. Everything runs in your browser, and you can export the steps as code.
Related tool pages
- Export Data Cleaning Steps as SQL, pandas or PySpark Code: Clean or join a CSV in your browser, then export the steps as DuckDB SQL, pandas, PySpark or a dbt model. Free and private.
- Delete Columns from a CSV File: Remove one or more columns from a CSV or Excel file and download the result. Free, in your browser, and your file is never uploaded.
- Reorder Columns in a CSV File: Drag columns into a new order, or send a column to the start or the end, in a CSV or Excel file. Free, in your browser, nothing is uploaded.
- Remove Empty Rows and Columns from CSV: Remove rows with empty cells, rows that are completely empty, or columns with no values from a CSV or Excel file. Free, in your browser.
- Find and Replace in a CSV File: Find and replace text in a column of a CSV or Excel file, then download the result. Free, in your browser, and nothing is uploaded.
- Change Date Format in a CSV File: Change the date format of a column in a CSV or Excel file, for example 09/03/2026 to 2026-03-09, or get only the year or month. Free, in your browser.
Also try
How to use the Data Transformation: step by step
- Open Data Transformation and load a file.
- Add a step such as Calculated column or Group and summarize.
- Fill in the columns and check the preview.
- Download the result or export the code.
When to use the Data Transformation
- Totals per customer, region or month
- Computing price times quantity
- Pulling emails or order numbers out of notes
- Making IDs a fixed width for an import
Example
Input: plans.csv + customers.csv, key = id
Output: id, first_name, plan, amount
Frequently asked questions
Which transformations are available?
Join with a second file (inner, left, right, full), trim spaces, concatenate columns, change case, find and replace, split a column, rename, remove columns, reorder columns, remove empty rows or columns, filter rows, remove duplicates, sort and fill empty cells.
Can I run several steps?
Yes. Steps run from top to bottom and each one sees the result of the one before. You can reorder or remove them.
Can I join two files or combine columns?
Yes. Data Transformation lets you join two CSV or Excel files on a key (inner, left, right or full), and trim spaces, concatenate columns, change case, find and replace, split, rename, filter, sort, remove duplicates and fill empty cells. You choose the steps, check the result and download it. Your files stay in your browser.
Can I export my transformations as code?
Yes. After you add and fill in your steps, open Export recipe as code under the result. Choose DuckDB SQL, Python (pandas), PySpark or a dbt model, then copy or download the code. It is a readable starting point: run it on a small sample first and adapt it for your own pipeline. The DuckDB SQL is checked against the real DuckDB engine for every step.
Tip: Chain steps: add a calculated total, then group by customer and sum it.