# Decimal to Percentage Converter

Created by Rita Rain
Reviewed by Dominik Czernia, PhD candidate and Jack Bowater
Last updated: Dec 08, 2021

The decimal to percentage converter (a.k.a. convert decimal to percent calculator) lets you turn a decimal value into a percentage. As it calculates in both directions, it can also serve you as the percent to decimal converter.

Read the text below to learn how to convert decimal to percent and turn percent to decimal on your own.

## What are decimals? - an introduction

Hindu–Arabic numeral system (or Indo-Arabic numeral system) is the decimal positional system, nowadays the most commonly used numeral system in the world. Other systems include the binary and hexadecimal system.

Let's explain what it means. "Decimal" means the system is based on 10. "Positional notation" means we assign a different value to a symbol depending on its position. For example, digit "3" in "13" equals 3, but in "342" it equals 300.

The system is much more practical than alternatives like representing numbers with lines (that's what some ancients would do). So instead of having "|||||||||||||||" you just write "15". This way, using ten symbols (0-9), we can represent any rational number.

If we were to write a general formula for a 4-digit number, it could look like this:

a₃a₂a₁a₀ = a₃*1,000 + a₂*100 + a₁*10 + a₀*1

The symbol "a" here stands for a digit from 0 to 9. The index next to "a" denotes the digit's place (we count from 0, from right to left).

To get the number (right side of the equation), we multiply each digit by the powers of ten (1, 10, 100, ...). The indexes tell us how many zeros the powers of ten have to have. If a digit is on the "zeroth" place, we multiply by 1, on the first - by 10, on the second - 100, on the third - 1000, and so on.

We call places in the number after the powers of ten - the one's place, the ten's place, the hundred's place, and so on.

Take a look at examples:

11 = 1*10 + 1*1

23 = 2*10 + 2*1

145 = 1*100 + 4*10 + 5

43210 = 4*10000 + 3*1000 + 2*100 + 1*10 + 0*1

Now, what if you want to write down a decimal fraction?

The answer to the problem is using a decimal point - a dot (or a comma) - to separate whole numbers from fractions.

a₂a₁a₀.b₁b₂b₃ = a₂*100 + a₁*10 + a₀*1 + b₁/10 + b₂/100 + b₃/1000

To the left from dot we multiply by ten, to the right - we divide by ten.

Examples:

376.49 = 3*100 + 7*10 + 6 + 4/10 + 9/100

0.321 = 0*1 + 3/10 + 2/100 + 1/1000

## What are percents? - an introduction

Percent means "out of a hundred" (from Latin) and represents a ratio or number as a fraction of 100. We denote it with the percent sign "%":

1% = 1/100

For example, 15% is equal to 15/100 and means "fifteen out of hundred".

Examples:

• "40% of students in our school are female". The sentence implies that if the school has 100 students, 40 of them are girls.

• If you have a bowl with 100 corn flakes and you've eaten 20%, it means you've eaten 20 out of 100, so 20 flakes.

But it's not like we only talk about percents when there's 100 of something. Percents represent a ratio. Let's go through another example:

• In a forest, 60% of trees are deciduous trees. 10,000 trees grow in the forest. How many deciduous trees are there?

Remember:
1% = 1 / 100.

In this case:
60% = 60 / 100.

Once we have the fraction form, we can transform it. We know we have 10,000 trees, so we need to change the denominator:

60/100 = 60*100 / 100*100

60/100 = 6,000 / 10,000

The denominator expresses the number of all the trees, the numerator - the number of deciduous trees. Here is the answer - there are 6,000 leafy trees.

Both percents and decimals are common ways of representing fractions; let's learn how to convert between them.

🙋 We also use percent to express the relative error between the observed and true values in any measurement. To learn how to do that, check our percent error calculator.

## How to convert decimal to percent by hand?

This type of conversion is quite simple, so you should be able to do it without the decimal to percent calculator. You just need this formula:

percent = decimal * 100

To turn decimal to a percent, multiply the decimal by 100%.

## How to turn a decimal into a percent? - examples

Let's see how to turn a decimal into a percent in the below cases:

• 0.5 = 0.5 * 100%

0.5 = 50%

• 0.37 = 0.37 * 100%

0.37 = 37%

• 0.45372 = 0.45372 * 100%

0.45372 = 45.372%

Notice all you need to do is moving the decimal point two places to the right.

• 23.456 = 23.456 * 100%

23.456 = 2345.6%

You can practice with other numbers and check your answers using the decimal to percentage converter.

## How to use the decimal to percentage converter?

To use our convert decimal to percent calculator:

1. Input the decimal number you want to convert in the first field of the decimal to percentage calculator.

2. The decimal to percentage calculator will display the result below.

## How to convert percent to a decimal by hand?

To convert percent to decimal, simply divide by 100:

decimal = percent / 100

Let's say you've eaten 20% of a cake. To express this piece of cake as a decimal fraction, divide 20 by 100:

20/100 = 0.2

## How to turn a percent into a decimal? - examples

As always, a good bunch of examples will help you to understand how to turn a percent into a decimal:

• 40% = 40 / 100

40% = 0.4

• 676% = 676 / 100

676% = 6.76

• 0.022% = 0.022 / 100

0.022% = 0.00022

Again, all we're doing here is moving the decimal point two places to the left.

Come up with your own examples and check your results using this calculator as a percentage to decimal converter.

## Use our tool as a percentage to decimal converter

As we mentioned it many times before, you can use our calculator as a percentage to decimal converter:

1. Input the percentage first, in the second field of the percentage to decimal calculator.
2. Above, you'll see the decimal equivalent.

That's it! You can use our calculator quickly in two ways.

Rita Rain
Decimal
Percentage
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