Binary Fraction Converter
Our free binary calculator solves binary fraction problems. Get worked examples, visual aids, and downloadable results.
Reviewed by Manoj Kumar, Mathematics Educator
Formula
Decimal to Binary: Multiply fraction by 2, record integer part, repeat with remainder
To convert a decimal fraction to binary, repeatedly multiply the fractional part by 2. Each multiplication produces a binary digit (0 or 1) and a new fractional remainder. The process continues until the remainder is zero (terminating) or a pattern repeats (repeating fraction).
Worked Examples
Example 1: Converting 0.625 to Binary
Problem:Convert the decimal fraction 0.625 to its binary representation.
Solution:Using repeated multiplication by 2:\nStep 1: 0.625 x 2 = 1.25 -> bit = 1, remainder = 0.25\nStep 2: 0.25 x 2 = 0.5 -> bit = 0, remainder = 0.5\nStep 3: 0.5 x 2 = 1.0 -> bit = 1, remainder = 0.0\n\nResult: 0.101 in binary\nVerification: 1/2 + 0/4 + 1/8 = 0.5 + 0 + 0.125 = 0.625
Result:0.625 (decimal) = 0.101 (binary) = 5/8 as a fraction
Example 2: Converting 0.1 to Binary (Repeating)
Problem:Convert decimal 0.1 to binary and observe the repeating pattern.
Solution:Using repeated multiplication:\n0.1 x 2 = 0.2 -> 0\n0.2 x 2 = 0.4 -> 0\n0.4 x 2 = 0.8 -> 0\n0.8 x 2 = 1.6 -> 1\n0.6 x 2 = 1.2 -> 1\n0.2 x 2 = 0.4 -> 0 (pattern repeats)\n\nResult: 0.000110011001100... (repeating 0011)
Result:0.1 (decimal) = 0.0(0011) repeating in binary - cannot be exactly represented
Frequently Asked Questions
What is a binary fraction?
A binary fraction represents numbers between integers using powers of 2 with negative exponents, similar to how decimal fractions use powers of 10. After the binary point, the first position represents one-half (2 to the power of negative 1), the second represents one-quarter (2 to the negative 2), the third represents one-eighth, and so on. For example, binary 0.101 means 1 times one-half plus 0 times one-quarter plus 1 times one-eighth, which equals 0.5 plus 0 plus 0.125, giving 0.625 in decimal. Binary fractions are fundamental to how computers store and process non-integer numbers in all scientific, financial, and graphical computations.
How do you convert a decimal fraction to binary?
Converting a decimal fraction to binary uses the repeated multiplication method. Take the fractional part and multiply by 2. The integer part of the result becomes the next binary digit, and the fractional part carries forward. Repeat until the fractional part becomes zero or you reach the desired precision. For example, converting 0.375: multiply 0.375 by 2 to get 0.75 (bit is 0), multiply 0.75 by 2 to get 1.5 (bit is 1), multiply 0.5 by 2 to get 1.0 (bit is 1). The result is 0.011 in binary. This method works because each multiplication by 2 shifts the binary point one position to the right, revealing the next binary digit.
Why do some decimal fractions become repeating in binary?
A decimal fraction produces a terminating binary representation only if its denominator (when expressed as a fraction in lowest terms) is a power of 2. The fraction one-tenth (0.1) has a denominator of 10, which factors as 2 times 5. Since 5 is not a power of 2, one-tenth cannot be exactly represented in binary and produces the infinitely repeating pattern 0.0001100110011 repeating. This is analogous to how one-third (whose denominator 3 is not a power of 10) repeats infinitely in decimal as 0.333 repeating. This fundamental limitation affects all binary computing systems and is the root cause of floating-point rounding errors that programmers must carefully manage.
How do computers handle binary fractions internally?
Computers represent binary fractions using the IEEE 754 floating-point standard, which divides a number into three components: a sign bit, an exponent, and a mantissa (significand). For 32-bit single precision, there is 1 sign bit, 8 exponent bits, and 23 mantissa bits. For 64-bit double precision, there is 1 sign bit, 11 exponent bits, and 52 mantissa bits. The number is stored in scientific notation form as 1.mantissa times 2 to the exponent. This allows representation of very large and very small numbers but with limited precision. The mantissa determines the number of significant digits, which is about 7 for single and 15 to 17 for double precision.
References
Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy