1/5 as a Decimal – Complete Step-by-Step Conversion Guide

Understanding how to convert a fraction to a decimal is a fundamental math skill, and few conversions are as clean and straightforward as 1/5. Whether you are working on homework, calculating a tip, or reading a measurement, knowing that 1/5 as a decimal equals 0.2 saves time and reduces errors. This guide walks through the methods, shows related conversions, and answers common questions.

The fraction 1/5 represents one part out of five equal parts of a whole. Because the number 5 is a factor of 10, the decimal conversion terminates after just one decimal place, making it one of the easiest fractions to work with in decimal form.

What is 1/5 as a Decimal?

The decimal form of 1/5 is exactly 0.2. This is a terminating decimal, meaning it does not repeat infinitely. It is derived directly from the fraction’s numerator and denominator.

Key Insights

• 1/5 as a decimal is exactly 0.2, a terminating decimal with no repeating digits.
• Method 1 (denominator to 10): Multiply numerator and denominator by 2 to get 2/10 = 0.2.
• Method 2 (division): 1 ÷ 5 = 0.2, a method that works for any fraction.
• Students often confuse 1/5 = 0.2 with 1.5 (one point five) — they are different values.
• The same conversion applies to percentages: 1/5 = 20% by multiplying 0.2 × 100.
• Because the denominator 5 is a factor of 10, the decimal terminates after one digit.

Fact Table: 1/5 Conversion at a Glance

How to Convert 1/5 to a Decimal (Step by Step)

There are two reliable methods to convert 1/5 into a decimal. Each is explained below with clear steps.

How do you convert 1/5 into a decimal using division?

The most direct approach is to divide the numerator (1) by the denominator (5). Because 1 is smaller than 5, the result is less than 1. Place a decimal point after the 1 and add a zero, making it 10. Then divide 10 by 5, which gives 2. The result is 0.2. This division can be performed by hand using long division or with a calculator.

How to change 1/5 to a decimal using the power‑of‑10 method

If the denominator can be turned into a power of 10 (10, 100, 1000, etc.), the conversion is even simpler. Multiply both the numerator and denominator by the same number so that the denominator becomes 10. For 1/5, multiply by 2: (1 × 2)/(5 × 2) = 2/10. Then move the decimal point one place to the left: 2/10 = 0.2. This method is efficient when the denominator factors into 2 or 5.

What is 1/5 as a Percent?

To convert 1/5 to a percentage, multiply the decimal form (0.2) by 100. This gives 20%. Alternatively, you can convert the fraction directly: 1/5 = 20/100 = 20%. The percent form is frequently used in statistics, grades, and financial contexts.

Common Confusions: 1 1/5 and 1.5 as Decimals

Many learners mix up mixed numbers and decimal values. Here we clarify two frequent points of confusion.

What is 1 1/5 as a decimal?

The mixed number 1 1/5 means one whole plus one fifth. Convert the fractional part (1/5 = 0.2) and add the whole number: 1 + 0.2 = 1.2. Therefore, 1 1/5 as a decimal is 1.2. In percent form, that is 120%.

Why 1.5 is not the same as 1/5

A common error is to assume that 1.5 equals 1/5. In fact, 1.5 is one and five tenths, or 3/2. The decimal for 1/5 is 0.2, a completely different value. Always check the placement of the decimal point: one fifth is less than one, while 1.5 is greater than one.

Step-by-Step Conversion Process of 1/5 to Decimal

The following ordered list captures the long-division sequence used to convert 1/5 to decimal, as taught in many educational resources.

1. Set up the division: write 1 as the dividend and 5 as the divisor.
2. Since 5 cannot go into 1, place a decimal point after the 1 and add a zero, making the dividend 10.
3. 5 goes into 10 exactly 2 times. Write “2” after the decimal point.
4. Multiply 2 × 5 = 10 and subtract: 10 − 10 = 0.
5. The result is 0.2 with no remainder. (Source: CK-12 Flexi; also explained by Cuemath)

How Certain Is the Conversion of 1/5 to 0.2?

The mathematical relationship between 1/5 and 0.2 is absolute. However, some aspects of the broader topic remain uncertain for learners.

Why Does 1/5 Convert Easily to a Decimal?

The ease of conversion stems from the denominator 5 being a factor of 10. Fractions whose denominators have only the prime factors 2 or 5 produce terminating decimals. This is why 1/2 = 0.5, 1/4 = 0.25, and 1/5 = 0.2 all end after a short number of digits. In contrast, fractions like 1/3 or 1/7 produce repeating decimals. Understanding this pattern helps predict whether a fraction will have a terminating or repeating decimal.

Real‑world applications include dividing a restaurant bill (one‑fifth of the total), calculating a 20% tip (which is exactly 1/5 of the bill), and interpreting statistical data where proportions are expressed as decimals.

What Do Educational Sources Say About 1/5 as a Decimal?

“The decimal value of 1/5 is 0.2.”

— CK-12 Foundation (Flexi)

“1/5 as a decimal is 0.2.”

— Cuemath (pattern used across math education platforms)

Both sources present the same fact with consistent methodology, reinforcing the reliability of the conversion. Additional interactive tools are available on CalculatorSoup and Khan Academy for self‑practice.

Final Takeaway: What is 1/5 as a Decimal?

1/5 as a decimal is 0.2, a terminating decimal that also equals 20% in percentage form. The conversion is straightforward via division or the power‑of‑10 method. Once learned, this fact supports many everyday calculations and deeper fraction‑to‑decimal work. For further practice, try the Fraction to Decimal Calculator or learn How to Convert Decimals to Fractions.

Frequently Asked Questions About 1/5 as a Decimal