Rounding Calculator: Round to the Nearest Tenth, Hundredth, Whole Number and More
Round any number to the nearest thousand down to the nearest ten-billionth, by the half-up rule taught in school, the round-half-to-even rule NIST uses, or rounded up, rounded down or truncated.
To round, look at the first digit you are dropping. Below 5, the kept digit stays the same; 5 or more, it goes up by one. 3.14159 to the nearest hundredth is 3.14, and 2.675 is 2.68. When the dropped part is exactly a 5 with nothing after it, the half-to-even rule rounds to the even digit instead, so 2.5 becomes 2.
This calculator rounds the number you type exactly as written, in your browser. Rounding rules for prices, grades or lab reports can be set by a law, a contract or an instructor, so check which rule applies before relying on a rounded figure.
Rounded
3.14
3.14159 rounded to the nearest hundredths
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About the Rounding Calculator
Rounding keeps a number to a chosen place and drops the rest. The place can be anything from the thousands down to the ten-billionths, and the result is padded with zeros when your number has fewer decimals, so 3.1 to the nearest thousandth shows as 3.100. The default rule is round half up, the one commonly taught in school: a dropped 5 or more raises the kept digit, so 1450 to the nearest hundred is 1500, and a negative tie moves away from zero, so -2.5 becomes -3. The other common rule handles exact ties differently. NIST Special Publication 811, Appendix B.7.1, says that when the dropped digits are a 5 followed only by zeros, the kept digit stays if it is even and goes up if it is odd. That gives 2 for 2.5, 4 for 3.5 and 1400 for 1450. Three more rules ignore the halfway point: round up (the ceiling), round down (the floor) and truncate, which drops the digits and moves toward zero. All of it is done on the digits you type, not on floating-point numbers, so 2.675 rounds to 2.68 and not to the 2.67 a spreadsheet can sometimes show.
Frequently asked questions
Why does 2.675 sometimes round to 2.67?+
Many programming languages store decimals in binary floating point, and 2.675 cannot be written exactly that way, so it is held as a value just below 2.675 and rounds down. This calculator works on the digits as written, so 2.675 to the nearest hundredth is 2.68 under round half up, and 2.68 under half to even too, since the kept 7 is odd and goes up to 8.
What is the difference between rounding down and truncating?+
For positive numbers they agree: 3.29 rounded down or truncated to tenths is 3.2. For negative numbers they differ. Rounding down moves toward negative infinity, so -3.21 becomes -3.3, while truncating simply drops the digits and moves toward zero, so -3.29 becomes -3.2.
When should I use round half to even?+
Use it when you round many values and then add them, as in lab data, statistics or some accounting. Rounding every tie up adds a small upward bias to a total; sending ties to the even digit splits them up and down. For homework, follow the rule your teacher or textbook specifies.
How do I round to the nearest whole number?+
Choose whole number as the place. 7.4 rounds to 7 and 7.6 rounds to 8. An exact half such as 7.5 goes to 8 under round half up and also to 8 under half to even, since 8 is even; 6.5 goes to 7 under half up but to 6 under half to even.
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