Fraction Calculator

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Work with simple fractions, mixed numbers and decimals in basic mode, or type a whole expression with brackets in advanced mode. Every answer comes as a decimal and as a mixed fraction.

Created by the Reeliy Editorial Team. Last updated: Oct 19, 2026

Basic mode and advanced mode

The calculator has two modes, chosen with the Calculator mode switch.

Basic does one operation on two fractions. Type the first fraction, pick +, −, x, / or ^ from the drop-down list, then type the second fraction. Example: 3/4 + 1 1/2.
Advanced evaluates a whole expression, with as many terms and brackets as you like. Example: (3/4 + 1/6) / (2 - 1/3), or 2 x (1/2 + 1/3)^2.

Either way, the result is shown in two rows. Calculation result is the decimal value. Result as fraction is the same value written as a fraction, using a mixed number when the value is larger than 1.

What you can type

Input	Examples	Notes
Simple fraction	`3/4`, `7/9`	Write the numerator, a slash, then the denominator, with no spaces.
Mixed number	`2 1/3`, `4 5/8`	Type the integer, then a single space, then the fraction, as in 2 1/3.
Decimal	`1.5`, `0.75`, `0.5/1.25`	Use a dot as the decimal mark. Decimals may also sit inside a fraction.
Thousands separators	`2,500`, `1,250,000`	Commas between groups of three digits are ignored.
Negative numbers	`-1/2`, `-2 1/3`	A minus sign in front of a mixed number applies to the whole number, so −2 1/3 means −(2 + 1/3).
Pi	`pi`, `π/4`	Replaced by 3.14159265…, the ratio of a circle's circumference to its diameter.

Advanced mode reads these operator symbols: + adds, - subtracts, x or * multiplies, / or : divides, and ^ raises to a power. Round brackets group terms and override the default order of calculation.

Adding and subtracting fractions

Fractions can only be added or subtracted when they are counted in the same-sized pieces, so you first need a common denominator. The smallest one to use is the least common multiple of the two denominators, also known as the least common denominator. The LCD calculator and the LCM calculator find it for you.

a/b + c/d = (a × d + c × b) ÷ (b × d)This always works; using the least common denominator just keeps the numbers small.

Example, addition: 2/3 + 3/4. The least common denominator of 3 and 4 is 12. Rewrite 2/3 as 8/12 and 3/4 as 9/12, then add the numerators: 8 + 9 = 17. The answer is 17/12, which is the mixed number 1 5/12 or 1.416666666667 as a decimal.

Example, subtraction: 5/6 − 3/8. The least common denominator of 6 and 8 is 24. Then 5/6 = 20/24 and 3/8 = 9/24, so the difference is 11/24, or 0.458333333333. It cannot be reduced, because 11 is prime and does not divide 24.

Multiplying and dividing fractions

Multiplication needs no common denominator. Multiply the numerators together and the denominators together, then reduce. Division is multiplication by the reciprocal: flip the second fraction and multiply.

a/b × c/d = (a × c) ÷ (b × d)

a/b ÷ c/d = a/b × d/c = (a × d) ÷ (b × c)

Example, multiplication: 2/3 × 9/10 = 18/30. Both numbers share the factor 6, so this reduces to 3/5, which is 0.60.

Example, division: 3/4 ÷ 5/8 = 3/4 × 8/5 = 24/20, which reduces to 6/5, or 1 1/5 (1.20). Reducing is easiest with the greatest common divisor, and the simplify fractions calculator does it automatically.

Mixed numbers

A mixed number such as 2 1/4 is a whole number plus a fraction. Before calculating with it, rewrite it as an improper fraction: the new numerator is the integer times the bottom number plus the old top number, and the bottom number stays as it was. So 2 1/4 = (2 × 4 + 1)/4 = 9/4.

Example: 2 1/4 + 1 2/3. Convert both: 2 1/4 = 9/4 and 1 2/3 = 5/3. The least common denominator is 12, so the sum is 27/12 + 20/12 = 47/12, which is 3 11/12. In basic mode, type 2 1/4, choose +, then type 1 2/3. The calculator does the conversions itself.

Powers, roots and pi

The ^ operator raises the first value to the power of the second. A whole-number power of a fraction raises both parts: (3/5)² = 9/25 = 0.36, and a negative power flips the fraction, so (1/2)⁻² = 4.

A power written as a fraction is a root. An exponent of 1/2 is a square root, 1/3 a cube root and so on. In advanced mode 9^1/2 is read as 9 to the power 1/2 and gives 3. See also the exponent calculator for decimal and negative powers.

When the true answer is irrational, a fraction can only approximate it. The square root of 2 is shown as 1.414213562373, with the fraction 1 408/985, which equals 1.41421320 and is off by less than one part in a million. Likewise, π/2 + 1 gives 2.570796326795 and the fraction 2 129/226. Trust the decimal for precision and treat the fraction as a convenient short form.

A negative number raised to a fractional power, such as −8 to the power 1/3, has no real result in this calculator, so no answer is shown.

Order of operations in advanced mode

Expressions follow the standard order: brackets first, then exponents, then multiplication and division from left to right, then addition and subtraction from left to right.

Example: (1/2 + 1/3) * 6 - 2 : 4. The bracket gives 1/2 + 1/3 = 5/6. Multiplying by 6 gives 5. Next, 2 ÷ 4 = 0.5. Finally 5 − 0.5 = 4.5, shown as 4.50 and as the fraction 4 1/2.

Division chains run from left to right, so 8/2/2 is (8 ÷ 2) ÷ 2 = 2, not 8 ÷ (2 ÷ 2) = 8. Add brackets whenever you mean the second reading.

Common mistakes

Adding the numerators and the denominators. 1/2 + 1/3 is not 2/5. Find a common denominator first: 3/6 + 2/6 = 5/6.
Forgetting to flip when dividing. Dividing by 5/8 means multiplying by 8/5.
Typing a mixed number without the space. 21/3 is the fraction 21/3 = 7, whereas 2 1/3 is two and a third.
Misreading the minus sign. −2 1/3 is minus two and a third, not −2 + 1/3.
Rounding in the middle of a calculation. Keep fractions exact until the last step, then convert to a decimal. Use the fraction to decimal calculator, the fraction to percent calculator or the decimal to fraction calculator to move between forms.

Frequently asked questions

How do I enter a mixed number such as 2 1/3?

Type the whole number, one space, then the fraction: 2 1/3. Without the space the calculator reads 21/3 as an ordinary fraction. A leading minus sign applies to the whole mixed number.

How do I add fractions with different denominators?

Rewrite both with a common denominator, add the numerators and keep the denominator, then simplify. For 2/3 + 3/4, use 12: 8/12 + 9/12 = 17/12 = 1 5/12. The calculator does all of this when you press Calculate.

Why does the fraction differ slightly from the decimal?

When the exact value cannot be written as a short fraction, which happens with square roots and with pi, the calculator gives a close fraction that is within about one part in a million of the true value. The decimal is more precise.

Can I use decimals and pi in the same calculation?

Yes. Decimals such as 1.5 work in both modes, including inside a fraction like 0.5/1.25, and you can write pi or π anywhere a number is allowed.

How do I take the square root of a fraction?

Raise it to the power 1/2. In basic mode, enter the fraction, choose ^ and type 1/2 as the second fraction. In advanced mode, write the fraction in brackets followed by ^1/2, for example (9/16)^1/2, which gives 3/4.

Cite this calculator and page

If you use this page in your work, you can cite it as:

Reeliy Editorial Team. (2026). Fraction Calculator. Reeliy. https://reeliy.com/calculators/fractions-calculator“Fraction Calculator.” Reeliy, 2026, https://reeliy.com/calculators/fractions-calculator.