Rounding Calculator
Round a number to a chosen number of decimal places, significant figures, or the nearest ten, hundred or thousand.
Rounded result
How we calculated this
Worked example
3.14159 rounded to 2 decimal places is 3.14.
How it works
This tool rounds a number to a chosen number of decimal places, to a chosen number of significant figures, or to the nearest ten, hundred, thousand and so on, using the conventional "round half away from zero" rule: an exact halfway value always rounds outward, away from zero (2.5 rounds to 3, and −2.5 rounds to −3, never towards zero). Some other calculators round a negative halfway value towards zero or towards positive infinity instead, which can give −2 for −2.5; this one does not.
The calculation corrects for a well-known quirk of computer arithmetic. A value like 1.005 can be stored internally as very slightly less than 1.005, which would otherwise cause it to round down instead of up, and this correction is applied consistently regardless of how large or small the number is.
It does not offer unlimited precision: decimal places are limited to 10, and significant figures to 15, beyond which ordinary computer number storage is no longer reliably exact. Rounding to the nearest ten, hundred or thousand accepts whole-number magnitudes up to 9,007,199,254,740,991 for the same reason.
What this result means
The result is your number rounded to the number of decimal places or significant figures you chose, or to the nearest ten, hundred, thousand or larger power of ten. An exact halfway value rounds away from zero.
Examples
- 12,345 rounded to 3 significant figures: 12,300
Common mistakes
- Significant figures mode does not pad the result with trailing zeros to show precision, so 100 to 5 significant figures is still shown as 100, not 100.00.