Convert Case in Arrow Files Online
Convert text columns to UPPERCASE, lowercase, or Title Case in Arrow files directly in your browser. Apply case conversion to any or all text columns at once — no upload required.
How to convert Case in Arrow files
- Drop your file onto the upload area. Every text column is ticked by default and the first 200 rows are shown.
- Choose the case type: UPPERCASE, lowercase or Title Case. One case type applies to every ticked column in a run.
- Adjust the columns under Apply to columns. Only text columns are listed. The All and None links tick or clear them all.
- Click Convert Case, check the preview, and download the file in the same format.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
Newsletter sign-ups were merged from two web forms, and email addresses arrive in mixed case. The mailing tool treats Jo.Bloggs@Example.COM and jo.bloggs@example.com as different contacts.
Input (Arrow)
Arrow IPC file (binary, columnar) — shown as a table with its schema
| country | visits | |
|---|---|---|
| Jo.Bloggs@Example.COM | NZ | 3 |
| mika.k@example.fi | fi | 1 |
| ANNA.W@EXAMPLE.DE | DE | 7 |
| r.osei@example.gh | GH | 2 |
Schema: email VARCHAR, country VARCHAR, visits BIGINT
Settings
- Case type: lowercase
- Apply to columns: email only (country unticked; visits is a number and is not listed)
Result
| country | visits | |
|---|---|---|
| jo.bloggs@example.com | NZ | 3 |
| mika.k@example.fi | fi | 1 |
| anna.w@example.de | DE | 7 |
| r.osei@example.gh | GH | 2 |
Only the email column changes. Addresses that were already lowercase are left as they were. The country column was unticked, so "fi" is still lowercase. A second run with UPPERCASE and only country ticked would fix it. The visits column is a number and passes through unchanged.
Frequently Asked Questions
Can I apply different cases to different columns?
Not in one run. Each run applies one case type to all ticked columns. Run the tool again on the downloaded file with the other columns ticked.
Which columns can I convert?
Text columns only, and those are the only ones listed. Number, date and boolean columns have no letters to convert, so they are left unchanged.
Does it trim spaces or fix accents?
No. It only changes letter case. Accented letters are converted correctly, for example é to É, but spaces and punctuation are left alone. Use Trim Whitespace for spaces.
Related Tools
Deduplicate CSV Files Online
Remove duplicate rows from CSV files instantly in your browser. No upload, no server — 100% private.
Trim Whitespace in CSV Files Online
Trim leading and trailing whitespace from all text columns in CSV files, directly in your browser. No upload required.
Count Values in CSV Files Online
Group and count rows by any column in CSV files directly in your browser. Sort by frequency or value to find the most common entries — no upload required.
Convert Case in CSV Files Online
Convert text columns to UPPERCASE, lowercase, or Title Case in CSV files directly in your browser. Apply case conversion to any or all text columns at once — no upload required.
Convert Case in Excel Files Online
Convert text columns to UPPERCASE, lowercase, or Title Case in Excel files directly in your browser. Apply case conversion to any or all text columns at once — no upload required.
Convert Case in Parquet Files Online
Convert text columns to UPPERCASE, lowercase, or Title Case in Parquet files directly in your browser. Apply case conversion to any or all text columns at once — no upload required.
Convert Case in JSON Files Online
Convert text columns to UPPERCASE, lowercase, or Title Case in JSON files directly in your browser. Apply case conversion to any or all text columns at once — no upload required.
Arrow Viewer Online
View and inspect Arrow files directly in your browser. Browse rows, check column names and data types — no upload required, your data stays on your device.