Rounding Calculator
Round a number to a chosen number of decimal places or significant figures.
Rounding, done right
Rounding replaces a number with a nearby simpler one, to a chosen level of precision. This rounds to decimal places or significant figures, handling the rules consistently so you get the correct rounded value.
Enter a number and choose how to round it.
The subtleties people miss
Rounding seems simple but has genuine subtleties. The basic rule — round half up — is familiar, but there is also a less-known convention, round half to even, used in many scientific and financial contexts to avoid a slight upward bias when rounding lots of numbers. A common error is rounding in stages, where rounding an already-rounded number compounds the error; it is better to round once, from the original. Decimal places and significant figures are also different things: two decimal places fixes the digits after the point, while two significant figures fixes the number of meaningful digits regardless of the decimal point, which matters for very large or small numbers. Getting these right keeps rounded results honest.
Common questions
What is the difference between decimal places and significant figures?
Decimal places fix the digits after the point; significant figures fix the count of meaningful digits regardless of the point, which matters for very large or small numbers.
Why avoid rounding in stages?
Because rounding an already-rounded number compounds the error. Rounding once from the original value is more accurate.
Is anything uploaded?
No. The calculation happens in your browser.