Add mixed and proper fractions
2 1/3 + 3/4 becomes 7/3 + 3/4. A denominator of 12 gives 28/12 + 9/12 = 37/12, or 3 1/12.
Calculate with exact fractions
Examples: 7/8, −2 1/3, 5. Use a normal minus sign (-) when typing.
Results
Reduced fraction
37/12
Mixed number
3 1/12
Decimal expansion
3.083333333333…
Before reduction
(7 × 4 + 3 × 3) / (3 × 4)
Signs are moved to the numerator. A minus sign on a mixed number applies to the entire amount.
Calculations and exports run locally in your browser. Your entries are not sent to a calculation service.
How to use the Fraction Calculator
- 01
Enter each operand as a whole number, a fraction such as 7/8, or a mixed number such as 2 1/3.
- 02
Choose addition, subtraction, multiplication, or division.
- 03
Inspect the reduced fraction and intermediate products. Copy or download all result forms together.
Examples
Divide by a fraction
3/5 divided by 9/10 equals 3/5 × 10/9 = 30/45 = 2/3. Its decimal repeats, so the displayed decimal ends with an ellipsis.
A negative mixed number
−2 1/3 means the negative of the entire mixed number: −7/3. It does not mean −2 plus 1/3.
Reduce by a common divisor
The calculator keeps an integer numerator and denominator and divides both by their greatest common divisor. A negative denominator is normalized so that the sign appears in the numerator. Exact integer arithmetic also works for values beyond JavaScript’s usual safe-integer range.
See the operation before reduction
Addition and subtraction use cross products over the product of the denominators. Multiplication combines numerators and denominators directly. Division multiplies by the second fraction’s reciprocal. The displayed intermediate expression is useful for spotting an input or sign mistake.
Mixed-number input conventions
Put a space between the whole number and fraction. The fractional part may be improper, such as 1 5/3, and the result is still normalized. Mixed-number fractional numerators and denominators must be nonnegative integers; use a sign before the whole number to negate the entire value.
What to know
- Each integer component accepts up to 300 digits.
- No symbolic variables, nested expressions, or Unicode fraction glyphs are parsed.
Common questions
Can a denominator be zero?
No. A fraction with denominator zero is undefined. Dividing by a fraction whose numerator is zero is also rejected.
Can I enter decimal operands?
This tool expects integer fraction notation. Express 0.25 as 1/4, or use the percentage calculator for decimal arithmetic involving rates.
Is the decimal exact?
A terminating decimal is exact when all its digits fit the display. Repeating or longer expansions are truncated after 12 places and marked with an ellipsis; the reduced fraction remains exact.