This rounding calculator rounds a number to the place you choose, from thousands down to ten-thousandths, and compares five rounding methods side by side.
Rounding methods
- Half away from zero: the standard school method; 2.5 becomes 3 and −2.5 becomes −3.
- Half to even (banker’s rounding): a 5 rounds to the nearest even digit, so 2.5 becomes 2 and 3.5 becomes 4. It avoids bias in large data sets.
- Ceiling: always rounds up.
- Floor: always rounds down.
- Truncate: simply cuts off the extra digits.
Worked example
Rounding 3.14159 to the nearest hundredth gives 3.14, because the next digit, 1, is less than 5.
Frequently asked questions
Why do some calculators round 1.005 to 1.00?
Computers store some decimals inexactly, so 1.005 may be stored as 1.00499… This calculator shifts the decimal point as text first to avoid that problem.
What is the difference between floor and truncate?
They match for positive numbers, but differ for negatives: floor(−2.7) is −3, while truncating gives −2.