Why can you not add denominators when adding fractions?
The denominator indicates the size or total number of equal parts that make up a whole. Adding denominators changes the size of the units rather than counting how many units you have. For example, 1/4 + 1/4 means two fourth-sized pieces, which equals 2/4 (or 1/2), not 2/8 (which is 1/4).
What is the fastest way to add fractions with different denominators?
The fastest method is cross-multiplication: multiply the top of the first by the bottom of the second, add the product of the top of the second and bottom of the first, and place the result over the product of both denominators.
Can this tool add mixed numbers?
To add mixed numbers using this tool, convert the mixed numbers into improper fractions first (Multiply whole number by denominator, add numerator). Enter the improper fractions into the input fields.
How do you simplify the sum after adding?
Find the Greatest Common Divisor (GCD) of the sum numerator and denominator. Divide both numbers by that GCD.
Does order matter when adding fractions?
No. Addition of fractions is commutative, meaning (a/b) + (c/d) produces the exact same sum as (c/d) + (a/b).
How accurate is the result?
Results use JavaScript's 64-bit floating point — accurate to 15+ significant digits for most calculations.
Can I enter decimal numbers?
Yes, decimals are fully supported.
Is it free?
Yes, completely free.
Does it show the formula?
Yes, the formula is displayed on the page.
Can I use it on mobile?
Yes, the calculator is fully responsive.
Does it save my inputs?
No data is stored — all calculations are done locally in your browser.
What if I get an error?
Check for invalid inputs such as division by zero or negative square roots.