Fraction Calculator
Add, subtract, multiply, and divide fractions.
Runs locally in your browser
Your inputs are processed locally in your browser and are not uploaded or stored by us.
Add, subtract, multiply, and divide fractions using exact integer arithmetic.
How to calculate fractions
- Enter the numerator and denominator for the first fraction.
- Select your mathematical operation (+, −, ×, ÷).
- Enter the numerator and denominator for the second fraction.
- The calculator will compute the exact mathematical result and simplify it to its lowest terms.
Fraction Arithmetic Formulas
Addition: a/b + c/d = (ad + bc) / bd
Subtraction: a/b − c/d = (ad − bc) / bd
Multiplication: a/b × c/d = ac / bd
Division: a/b ÷ c/d = ad / bc
The calculator computes the raw fractional result using these exact formulas, then simplifies the answer by dividing both the numerator and denominator by their greatest common divisor.
Adding 1/2 and 1/3
Fraction 11 / 2
Operation+
Fraction 21 / 3
= (1×3 + 1×2) / (2×3)
= (3 + 2) / 6
Result: 5 / 6
Notes
- The calculator preserves exact integer relationships within JavaScript’s safe-integer range.
- Fraction calculations use safe integer arithmetic. If an intermediate integer operation would exceed JavaScript’s safe-integer range, the calculator rejects the calculation rather than silently returning an approximate fraction.
- Denominators cannot be zero, and dividing by a zero fraction is invalid.
- Negative fractions are supported. A negative denominator is automatically normalized so the negative sign appears on the numerator.
- Your inputs are processed locally in your browser and are not uploaded or stored by us.