Math Calculators
Rounding Calculator

Rounding Calculator

This rounding calculator rounds off numbers to the nearest whole number, significant digit, or decimal place. You can round the decimal numbers to the nearest tenths, hundredths, or thousandths.

Rounded Number


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Table of Contents

  1. Using the rounding numbers calculator
  2. Rounding to the nearest whole number
  3. Rounding decimal numbers to significant digits
  4. How to round numbers without a calculator
  5. Making the Numbers Simpler

Rounding Calculator

Using the rounding numbers calculator

Start by entering the value that you want to round. Note that you should enter only numbers and decimal points in this space. You cannot enter any other special characters or letters. Once you have entered the value you need to round off, select the criteria for rounding.

There are two sets of options. One set has the option to round a number to a whole number or the nearest tens, hundreds, thousands, and so on, up to billions. Another set of parameters allows you to round the number to a certain number of decimal places.

Imagine a large value like 7,875,189. To simplify, you can round it to the nearest hundred thousand by entering the value and choosing 'hundred thousand' as the option.

We have the number 8 in the hundred thousandth place, and the following number in the ten thousandth place is 7, which is greater than 5. According to the rule of rounding numbers, the number in the hundred thousandth place is rounded up to the next digit, 9. The digit in the ten thousandth place (7) affects the rounding of the digit in the hundred thousandth place (8).

So, we get 7,900,000 as the final result.

Rounding to the nearest whole number

Let's say your weight is 110.45 lbs. You decide to round it to the nearest whole number or one's place. Enter the actual value into the first blank and select option one's place (whole number) in the second blank. This will give you 110 lbs, as 0.45 is closer to 0 than 1. Now you have a simple weight that is easy to remember. Rounding to the one's place is the same as rounding to the nearest whole number.

Rounding decimal numbers to significant digits

When we encounter decimal numbers containing more than two digits after the decimal point, sometimes error-free processing of these digits becomes a difficult task. This is the case when we need to get the final result of a calculation or an intermediate number for further calculations.

The value and significance of the decimal digits decrease as you move further to the right. Therefore, if our task allows less accuracy and more ease of calculation, we have the opportunity to round the decimal number to the required number of significant digits.

The rounding decimal calculator has another set of options to round to the required decimal digits, i.e., tenths, hundredths, thousandths, hundred thousandths, or even billionths. The rounding decimal system can round the decimals from one decimal digit to nine decimal digits.

This decimal rounding calculator will be handy when you are in the process of a long mathematical calculation in which you, for example, get the value 1289.58794578. You can enter this value in the first blank space and choose to round it to two decimal digits or any number of digits of your choice. Select the necessary significant digit option for it, and you will have your answer of 1289.59 immediately.

How to round numbers without a calculator

Rounding is the replacement of a number by its approximate value (with a certain accuracy) written with fewer significant digits. The modulus of the difference between the initial and the rounded number is called the rounding error.

The result of rounding is called the approximate value of the number and is specified after the ≈ ("approximately equal").

All numbers with more than one digit have more than one digit place. This is the place in the number at which a particular digit exists. For example, the number 342 has three digit places: hundreds (three hundred), tens (four tens), and units (two ones). Accordingly, you can round numbers to the tens, hundreds, thousands, and so on.

When rounding, digits in places we do not need are replaced by zeros (in fact, they are discarded), and the digit we need either increases or remains unchanged, depending on what digit falls after it. If the unneeded digit is from 0 to 4, the preceding digit remains unchanged. If the unneeded digit is from 5 to 9, 1 is added to the digit preceding it.

Take the number 31,769. It can be rounded as follows:

  • To tens. The number of tens in the number 31,769 is six. There is 9 after the 6, so the number of tens increases by one during rounding. The answer is 31,770.
  • To hundreds. The number of hundreds in the number 31,769 is seven. The digit after seven is 6, so we add one to the number of hundreds. The result is 31,800.
  • To thousands. The number of thousands is 1. This is followed by seven, so if you round the number, you would add one digit for the thousands, resulting in 32,000.

The same rules apply to rounding fractions as apply to rounding natural numbers. You need to be more careful because there are more digits in fractions, both in integers (ones, tens, hundreds, thousands, etc.) and in the fractional part (tenths, hundredths, thousandths, etc.).

For example, take the decimal fraction 55.836. It can be rounded as follows:

  • to hundredths → 55.84;
  • to tenths → 55.8;
  • to integers → 56;
  • to tens → 60.

Making the Numbers Simpler

Rounding numbers is beneficial when solving problems and when you need to roughly calculate the cost of something to see if it fits your budget.

We can recollect at least one incident where we picked an item at a store, and the price tag read $399. It takes a moment to realize that $399 is closer to $400 than $300. Again, at the billing, if the bill is $789, it takes some more thinking to realize that the bill amount is closer to $1,000 than $500.

How do we come to this conclusion? This is what rounding numbers is all about. Rounding makes numbers simpler and easier to understand. It is not only the currency values we need help rounding all the time. There are distances, weights, temperatures, and many other measurements that we can round to simpler numbers to make them easier to understand.

Rounding helps in numerous instances. For example, when you want to estimate the result of the multiplication of large numbers. Let's say you would like to know what 838 × 56 is. According to rounding rules, it is approximately 800 × 60. It turns out: 838 × 56 ≈ 800 × 60 ≈ 48,000. The exact result of the multiplication is 46,928.

Rounding is also used when absolute accuracy is not essential. For example, if someone you know from out of town asks you how many people live in your town, you're unlikely to give the number in tens and ones, even if you know it. You are more likely to say that "about four hundred thousand" or "about a million" people live there.

The whole rounding task becomes easier when you can do it on a rounding calculator. This calculator has all the rounding functions you need to round a whole number or decimal up or down. We can round the numbers to the nearest ones; tens, hundreds, thousands, and so on.

The significance of knowing the concept of rounding numbers is not only a part of mathematical or statistical calculations. It also applies to day-to-day dealings with numbers like money, distances, temperature, and other measurable quantities.