Fraction Calculator

About the Fraction Calculator

A fraction calculator performs all arithmetic operations — addition, subtraction, multiplication, and division — on fractions and mixed numbers, and simplifies any fraction to its lowest terms. Fraction arithmetic is a fundamental mathematics skill that underpins algebra, geometry, calculus, cooking and recipe scaling, woodworking measurements, financial ratios, and probability calculations. Yet fraction arithmetic with different denominators is a step many people find genuinely confusing, making a reliable fraction calculator an essential tool for students from 4th grade through college algebra and for adults doing practical calculations involving measurements and ratios. Our free fraction calculator shows every step of the working — including how the common denominator is found, how numerators are adjusted, how the result is simplified using the GCF, and how improper fractions are converted to mixed numbers — making it both a calculating tool and a learning resource. It handles proper fractions, improper fractions, mixed numbers, negative fractions, and whole numbers in any combination.

How It Works

Addition and subtraction: find the LCD (Least Common Denominator) of both fractions, convert each fraction to an equivalent fraction with the LCD as the denominator, then add or subtract the numerators, keep the denominator. Example: 3/4 + 2/6. LCD of 4 and 6 = 12. Convert: 9/12 + 4/12 = 13/12 = 1 and 1/12. Multiplication: multiply numerators together, multiply denominators together, then simplify. 3/4 x 2/5 = 6/20. GCF(6,20) = 2. Simplified: 3/10. Division: multiply by the reciprocal (flip the second fraction, then multiply). 3/4 / 2/5 = 3/4 x 5/2 = 15/8 = 1 and 7/8. Simplification: divide numerator and denominator by their GCF. 24/36: GCF(24,36) = 12. 24/12 = 2, 36/12 = 3. Simplified: 2/3. Mixed numbers: convert to improper fraction first (whole number x denominator + numerator / denominator), perform the operation, convert back.

Tips & Best Practices

• ✓Finding LCD: the Least Common Denominator is the LCM (Least Common Multiple) of both denominators. Factor each denominator and take the highest power of each prime factor.
• ✓Cross-cancellation before multiplying saves simplification steps: in (8/15) x (5/12), cancel 5 from numerator with 15 in denominator (divide both by 5), and cancel 8 with 12 (divide both by 4). Result is 2/9 immediately — no post-multiplication simplification needed.
• ✓Mixed number to improper fraction: multiply the whole number by the denominator, add the numerator, keep the same denominator. 3 and 2/5 = (3x5 + 2)/5 = 17/5.
• ✓A fraction is fully simplified when the numerator and denominator share no common factors other than 1 — equivalently, when GCF(numerator, denominator) = 1.
• ✓Negative fractions: -3/4, 3/-4, and -(3/4) are all equivalent. The standard convention places the negative sign in front of the entire fraction, not on the denominator.
• ✓Fraction to decimal: divide the numerator by the denominator. 3/8 = 3 / 8 = 0.375. Some fractions produce repeating decimals: 1/3 = 0.333... The calculator shows both forms.
• ✓Recipe scaling with fractions: scaling a recipe that calls for 2/3 cup down to 3/4 of the recipe: 2/3 x 3/4 = 6/12 = 1/2 cup. Fraction multiplication is the standard tool for recipe scaling.
• ✓Comparing fractions: to compare 5/8 versus 7/11, convert both to the LCD (88): 55/88 versus 56/88. So 7/11 is slightly larger than 5/8 — cross-multiplication (5x11=55 vs 7x8=56) gives the same result faster.

Who Uses This Calculator

Elementary and middle school students completing fraction homework use the calculator to verify answers and understand where they went wrong when their manual calculation differs from the correct result. High school students in pre-algebra and algebra use it for problems involving rational expressions that require the same fraction arithmetic skills. Cooks and bakers scale recipes up and down using fraction multiplication and division — halving a recipe that calls for 3/4 cup means 3/4 x 1/2 = 3/8 cup. Woodworkers and craftspeople work with fractional inch measurements (3/8", 11/16") and need to add and subtract fractions to calculate cuts. Financial analysts work with ratio comparisons expressed as fractions. Physics and chemistry students perform calculations involving fractional quantities and rational numbers. Teachers create fraction worksheets and check answer keys. Anyone who last studied fractions decades ago and needs a refresher tool for a practical calculation.