Last updated: March 2026
How to Convert Fractions to Decimals
Converting a fraction to a decimal is straightforward: divide the numerator by the denominator. For example, 3/8 = 3 ÷ 8 = 0.375. Some fractions produce clean terminating decimals (like 1/4 = 0.25) while others produce repeating decimals (like 1/3 = 0.333...).
A fraction will produce a terminating decimal when the denominator's only prime factors are 2 and 5. Denominators like 4, 8, 10, 20, and 25 always terminate. Denominators with other prime factors (3, 7, 11, etc.) produce repeating decimals.
Common Fraction-Decimal Equivalents
Memorizing common conversions speeds up mental math: 1/2 = 0.5, 1/4 = 0.25, 3/4 = 0.75, 1/3 ≈ 0.333, 2/3 ≈ 0.667. The reference table above shows the 10 most commonly needed fraction-decimal equivalents.
For quick estimation, remember that eighths go by 0.125: 1/8 = 0.125, 2/8 = 0.25, 3/8 = 0.375, 4/8 = 0.5, 5/8 = 0.625, 6/8 = 0.75, 7/8 = 0.875. These come up frequently in cooking, construction, and everyday measurements.
Frequently Asked Questions
How do you convert a fraction to a decimal?
Divide the numerator by the denominator. For example, 3/4 = 3 ÷ 4 = 0.75. Some fractions produce repeating decimals: 1/3 = 0.333... (the 3 repeats forever). This is written as 0.3̄ with a bar over the repeating digit.
How do you convert a decimal to a fraction?
Count the decimal places and use that as the denominator power of 10. For 0.75: that's 75/100. Then simplify: GCD(75, 100) = 25, so 75÷25 / 100÷25 = 3/4. For repeating decimals like 0.333..., the fraction is 1/3.
What is 1/3 as a decimal?
1/3 = 0.33333... (repeating). This is a non-terminating, repeating decimal. It's often rounded to 0.333 or 0.33 depending on the precision needed. As a percentage, it's approximately 33.33%.
Why do some fractions produce repeating decimals?
A fraction produces a terminating decimal when its denominator (in simplest form) has only 2 and 5 as prime factors. If the denominator has any other prime factor (like 3, 7, 11), the decimal repeats. For example: 1/4 = 0.25 (terminates) but 1/6 = 0.1666... (repeats).
What is 7/8 as a decimal?
7/8 = 0.875. Since 8 = 2³ (only has 2 as a prime factor), this produces a terminating decimal. As a percentage, 7/8 = 87.5%.
How do you convert a mixed number to a decimal?
Convert the fraction part to a decimal and add it to the whole number. For example, 2¾ = 2 + 3/4 = 2 + 0.75 = 2.75. Or first convert to an improper fraction: 2¾ = 11/4, then divide: 11 ÷ 4 = 2.75.