Round Numbers in JSON Files Online
Round numeric columns in JSON files to any number of decimal places directly in your browser. Set precision per column with a simple slider — no upload required.
About this tool
Round numeric columns in a JSON file to any number of decimal places — or to the nearest 10, 100, or 1 000 — directly in your browser. Choose from standard rounding, floor, ceil, or truncate. Select as many columns as you need and download the result. Nothing leaves your device.
Frequently Asked Questions
What rounding methods does the JSON round numbers tool support?
The tool supports standard rounding (round half away from zero), floor (always round down), ceil (always round up), and truncate (strip decimal places without rounding). Each method can be applied to any numeric column independently.
How many decimal places can I round to in a JSON file?
Any number from 0 (whole numbers) to 15. Set a negative value to round to the nearest 10, 100, or 1 000 — for example -2 rounds 1 234 to 1 200. Useful for normalising financial figures or sensor readings.
Does rounding affect non-numeric columns in a JSON file?
No. Only the numeric columns you select are rounded. All other columns pass through unchanged with their original data types preserved.
Is my data private?
Yes — completely. Your file is never uploaded to any server. Everything runs locally in your browser using WebAssembly — processing happens entirely inside your tab. Once you close the tab, nothing is retained.
What is the maximum file size?
The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines handle 500 MB to 1 GB comfortably.
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