Round Decimals in a CSV
Round the numeric columns of a CSV to any number of decimal places, with the rounding mode you choose — half-up, half-even (banker's), ceil, floor, or truncate. Runs entirely in your browser; nothing is uploaded.
Round the numbers in a CSV, your way
Paste a CSV and this tool rounds its numeric cells to the number of decimal places you choose — locally in your browser, nothing is uploaded. Pick which rounding mode you want and, optionally, which columns to touch:
- Decimal places — keep 0 to 10 places.
- Rounding mode — how ties (a trailing
5) and every other digit are handled:- Half up — round halves away from zero (classical / spreadsheet
ROUND):2.5 → 3,-2.5 → -3. - Half down — round halves toward zero:
2.5 → 2. - Half to even — banker's rounding, which reduces bias:
0.5 → 0,1.5 → 2,2.5 → 2. - Ceil — always round up (toward +∞).
- Floor — always round down (toward −∞).
- Truncate — just drop the extra digits (toward zero).
- Half up — round halves away from zero (classical / spreadsheet
- Columns — leave blank to round every numeric column, or list columns by
header name and/or 1-based number (e.g.
price, 3). - Fixed formatting — turn on pad to a fixed number of decimals to always show
the full width, so
3becomes3.00at 2 places.
A first-row header is kept exactly as-is, and any non-numeric cell (text, a
$ price, a % value) passes through unchanged.
Worked example
With 2 decimal places, half up, and columns left blank, this input:
name,price,qty
Apple,1.005,3.14159
Pear,2.5,10
becomes:
name,price,qty
Apple,1.01,3.14
Pear,2.5,10
1.005 rounds to 1.01, 3.14159 to 3.14, and 2.5 / 10 already fit in two
places so they're unchanged. The name column is text, so it's left alone.
Why 1.005 rounds to 1.01 here (and not in a spreadsheet)
Most tools multiply by 100 and round, but 1.005 can't be stored exactly in
binary — it becomes 1.00499999…, so the naive result is 1.00. This tool rounds
on the decimal digits you typed, so 1.005 at two places gives the 1.01 you
expect.
FAQ
What's the difference between "half up" and "banker's" rounding?
Half up (the default) rounds a trailing 5 away from zero, so 0.5 → 1,
1.5 → 2, 2.5 → 3. Half to even (banker's) rounds a trailing 5 to the
nearest even digit, so 0.5 → 0, 1.5 → 2, 2.5 → 2. Banker's rounding is
common in finance and statistics because always rounding halves upward biases a
running total; sending them to the nearest even value cancels out over many rows.
How do I round only some columns?
Put the columns you want in the Columns box, separated by commas. You can mix
header names and 1-based numbers — price, 3 rounds the column named
price and the third column. Leave the box blank to round every numeric column.
Columns you don't list are copied through untouched.
What happens to text, blank, or currency cells?
Anything that isn't a plain number is left exactly as-is. A header row (when First
row is a header is on), a name like Apple, a blank cell, and a formatted value
like $12.99 or 4.7% all pass through unchanged — only clean numeric cells get
rounded.
Can I keep trailing zeros so every value has the same width?
Yes. Turn on Pad to a fixed number of decimals and every rounded cell shows
exactly the number of places you chose — 3 becomes 3.00 and 2.5 becomes
2.50 at two places. With it off, results are shown naturally, dropping trailing
zeros (2.50 → 2.5).
Can it read tab- or semicolon-separated files?
Yes. Set the Delimiter to match your file — a single character, or one of
comma / tab / semicolon / pipe. The output uses the same delimiter, and
quoted fields that contain the delimiter are parsed correctly.
Limits & edge cases
- Decimal places range from 0 to 10.
- Rounding operates on the digits you paste for plain decimals; values written in
scientific notation (
1.5e3) are rounded via floating point, which can differ in the last place for extreme inputs. - Numbers with thousands separators or symbols (
1,234.50,$9.99,50%) are treated as non-numeric and left unchanged — the comma is also a CSV delimiter, so strip separators before rounding. -0never appears: a value that rounds to zero is written as a plain0.- Everything runs in memory in your browser, so very large files are bounded by the memory available to the page.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool round-decimals "name,price,qty
Apple,1.005,3.14159
Pear,2.5,10"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/round-decimals/?data=name%2Cprice%2Cqty%0AApple%2C1.005%2C3.14159%0APear%2C2.5%2C10&decimals=2&mode=half_up&columns=price%2C%203&header=true&delimiter=%2C&trailing_zeros=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.