Round Numbers in Arrow Files Online
Round numeric columns in Arrow files to any number of decimal places directly in your browser. Set precision per column with a simple slider — no upload required.
How to round Numbers in Arrow files
- Drop your file onto the upload area. Every numeric column is listed with its type, ticked, and set to 2 decimal places.
- Untick columns you want to leave alone, such as IDs, or use the All and None links.
- Drag each column's slider to set its decimal places, from 0 to 6. Each column can have its own setting.
- Click Round, check the preview of the first 200 rows, 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
A rainfall log from regional weather stations carries GPS coordinates to five decimals and rainfall to three. A public dashboard only needs about 100 m accuracy and one decimal of rain.
Input (Arrow)
Arrow IPC file (binary, columnar) — shown as a table with its schema
| station | lat | lon | rain_mm |
|---|---|---|---|
| Kelburn | -41.28496 | 174.76785 | 12.46 |
| Ohakea | -40.20611 | 175.38872 | 0.05 |
| Paraparaumu | -40.90431 | 174.98556 | 3.349 |
| Masterton | -40.97512 | 175.63089 | NULL |
Schema: station VARCHAR, lat DOUBLE, lon DOUBLE, rain_mm DOUBLE
Settings
- lat: 3 decimal places
- lon: 3 decimal places
- rain_mm: 1 decimal place
Result
| station | lat | lon | rain_mm |
|---|---|---|---|
| Kelburn | -41.285 | 174.768 | 12.5 |
| Ohakea | -40.206 | 175.389 | 0.1 |
| Paraparaumu | -40.904 | 174.986 | 3.3 |
| Masterton | -40.975 | 175.631 | NULL |
Each column is rounded to its own number of places. Halves round away from zero, so 0.05 becomes 0.1 and -41.28496 becomes -41.285. Masterton has no reading and stays empty. The station column is text and is not listed. Rounding changes the stored value, not just the display.
Frequently Asked Questions
How are halves rounded?
Away from zero. 2.5 rounds to 3 and -2.5 rounds to -3 at 0 places. This matches Excel's ROUND, not the banker's rounding used by some programming languages.
Can I round down, round up, or truncate instead?
No. The tool only does standard rounding. For floor, ceiling or truncation, use the SQL workspace with floor(), ceil() or trunc().
Can I round to the nearest 10 or 100?
No. The slider runs from 0 to 6 decimal places. To round to tens or hundreds, use round(x, -1) or round(x, -2) in the SQL workspace.
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