Rounding Numbers Calculator

[ 13 Votes ]

The Rounding Numbers Calculator will calculate:

  1. The value of a given number when rounded to the nearest thousandth, hundredth, tenth, unit, ten, hundred, thousand, ten-thousand, hundred-thousand, million, ten-million, 100-million, billion, trillion, quadrillion and quintillion.

Rounding Numbers Calculator
Results (detailed calculations and formula below)
Orinigal number (n) =
to the nearest thousandth ≈
to the nearest hundredth ≈
to the nearest tenth ≈
to the nearest unit ≈
to the nearest ten ≈
to the nearest hundred ≈
to the nearest thousand ≈
to the nearest ten-thousand ≈
to the nearest hundred-thousand ≈
to the nearest million ≈
to the nearest ten-million ≈
to the nearest 100-million ≈
to the nearest billion ≈
to the nearest 10 billion ≈
to the nearest 100 billion ≈
to the nearest trillion ≈
to the nearest 10 trillion ≈
to the nearest 100 trillion ≈
to the nearest quadrillion ≈
to the nearest 10 quadrillion ≈
to the nearest 100 quadrillion ≈
to the nearest quintillion ≈
Rounding Numbers Calculator Input Values

Please note that the formula for each calculation along with detailed calculations is shown further below this page. As you enter the specific factors of each rounding numbers calculation, the Rounding Numbers Calculator will automatically calculate the results and update the formula elements with each element of the rounding numbers calculation. You can then email or print this rounding numbers calculation as required for later use.

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[ 13 Votes ]
Rounding Numbers. This image shows the properties and rounding numbers formula for the Rounding Numbers

Theoretical description

Rounding numbers means adjusting the digits (up or down) to make rough calculations easier. The result will be an estimated answer rather than a precise one. We use the symbol () to express rounding.

The easiest rounding is that to the nearest ten. In this case, the rounded value usually has one zero at the end, but in some cases it may has more than one. For example, we write 28 ≈ 30, 51 ≈ 50, 97 ≈ 100, etc.

The rule for rounding to the nearest ten

"If the ones (units) digit is 4 or less, the tens value does not change after rounding to the nearest 10; otherwise it increases by 1", as shown in the above examples.

In rounding to the nearest 100, the result will have at least 2 zeroes at the end but in specific cases it may have more. For example, 89 ≈ 100, 532 ≈ 500, 958 ≈ 1000, and so on.

The rule for rounding to the nearest hundred

"If the tens digit is 4 or less, the hundreds value does not change after rounding to the nearest 100; otherwise it increases by 1", as shown in the above examples.

In rounding to the nearest 1000, the result will have at least 3 zeroes at the end but in specific cases it may have more. For example, 569 ≈ 1000, 2132 ≈ 2000, 9758 ≈ 10,000, and so on.

The rule for rounding to the nearest thousand

"If the hundreds digit is 4 or less, the thousands value does not change after rounding to the nearest 1000; otherwise it increases by 1", as shown in the above examples.

We can extend the same approach for the rounding to the nearest ten thousand, hundred thousand and so on. In all cases, we have to consider the value on the left of the first digit that becomes zero after rounding and then apply the above rule.

We can also apply rounding to non-whole numbers as well. Thus, to round a number to the nearest unit, we must consider the tenth digit. If it is 4 or less, the units value remain unchanged, otherwise it increases by 1. For example, 324.5 ≈ 325, 57.198 ≈ 57, etc.

Likewise, in rounding to the nearest tenth, we must check the value of hundredths and apply the aforementioned rule, i.e. 3.574 ≈ 3.6 and so on.

Approximations Math Tutorials associated with the Rounding Numbers Calculator

The following Math tutorials are provided within the Approximations section of our Free Math Tutorials. Each Approximations tutorial includes detailed Approximations formula and example of how to calculate and resolve specific Approximations questions and problems. At the end of each Approximations tutorial you will find Approximations revision questions with a hidden answer that reveal when clicked. This allows you to learn about Approximations and test your knowledge of Math by answering the revision questions on Approximations.