Fraction calculator guide
Fractions represent a numerator divided by a denominator. This calculator keeps the exact fractional answer while also showing its decimal equivalent.
Enter whole-number numerators and denominators, select an operation, and calculate.
How to use the fraction calculator
- Enter fractions: Provide each numerator and nonzero denominator.
- Choose an operation: Select plus, minus, multiply, or divide.
- Calculate: Review the reduced fraction and decimal.
Formula and variables
Addition and subtraction use a common denominator; multiplication and division use cross-products.
a/b + c/d = (ad + cb) / bd- a,c — Numerators
- Top numbers of the input fractions
- b,d — Denominators
- Bottom numbers; neither may be zero
Add two fractions
Calculate 1/2 + 1/4.
- First fraction
- 1/2
- Second fraction
- 1/4
- Operation
- +
- Common denominator = 8
- 4/8 + 2/8 = 6/8
- Reduce by 2
Result: 3/4 = 0.75
The calculator returns the exact reduced fraction and decimal.
Understanding your results
Simplified result
A fraction is in lowest terms when numerator and denominator share no factor greater than one.
Assumptions
- Inputs are whole numbers.
- Denominators are nonzero.
Limitations
- Mixed-number text and symbolic variables are not accepted.
- Decimal inputs should be converted to fractions first for an exact result.
Common mistakes
- Adding denominators directly when adding fractions.
- Entering a zero denominator.
- Forgetting that division by a fraction means multiplying by its reciprocal.
Practical use cases
Recipe and measurement conversions
Combine fractional quantities while retaining exact values.
Math practice
Check common-denominator and reciprocal steps.
Frequently asked questions
How do you add fractions with different denominators?
Find a common denominator, convert each fraction, add the numerators, and simplify.
Why simplify a fraction?
Lowest terms make the value easier to compare and communicate without changing its value.
Sources and review
- Fractions — NIST Digital Library of Mathematical Functions. Accessed 2026-07-14.
Reviewed 2026-07-14.