Fraction Simplifier
Simplify a fraction to lowest terms, convert it to a decimal and percentage, and find the least common denominator between two fractions.
Fraction A simplified
2/3
Decimal / percentage
0.6667 = 66.67%
Least common denominator
72
A = 48/72, B = 27/72
A fraction is simplified by dividing both numerator and denominator by their greatest common divisor (GCD) — the largest whole number that divides evenly into both. The least common denominator (LCD) is the smallest number both denominators divide into evenly, used to compare or add fractions with different denominators.
About this tool
How to use it
- Enter Fraction A's numerator and denominator.
- Optionally enter Fraction B too, if you want to find the least common denominator between the two.
- Press Simplify, or just keep typing — the results update live.
- Read the simplified fraction, its decimal and percentage equivalent, and (if you entered Fraction B) the LCD section.
Why it matters
A fraction like 24/36 is correct but not in its simplest form — 2/3 says the same thing more clearly. Finding the greatest common divisor by hand for larger numbers is slow and error-prone, and finding a least common denominator to compare or add two fractions with different denominators adds another layer of arithmetic that's easy to get wrong.
When to use it
Useful for checking arithmetic or algebra homework, for simplifying a measurement or ratio down to its clearest form, or for finding a common denominator before adding or comparing two fractions by hand.
Good to know
A fraction is simplified by dividing both numerator and denominator by their greatest common divisor (GCD) — the largest whole number that divides evenly into both. The least common denominator (LCD) of two fractions is the smallest number both denominators divide into evenly; it's computed as the product of the two denominators divided by their GCD. A negative sign is always normalized onto the numerator, so a denominator is never shown as negative.
Common questions
What does it mean to simplify a fraction?
Simplifying (or 'reducing') a fraction means dividing both the numerator and denominator by their greatest common divisor, producing an equivalent fraction with the smallest possible whole-number numerator and denominator — 24/36 and 2/3 represent the exact same value, but 2/3 is fully simplified.
What is the least common denominator (LCD) used for?
The LCD is the smallest denominator two fractions can both be rewritten with, which is needed before you can directly add, subtract, or compare fractions that start with different denominators.
Why is Fraction B optional?
Fraction A's simplification, decimal, and percentage don't require a second fraction — the LCD calculation only makes sense (and only appears) once you've entered both a numerator and denominator for Fraction B.
What happens if I enter a negative denominator?
The negative sign is automatically moved to the numerator instead, since a fraction with a negative denominator (like 3/-4) is mathematically identical to one with a negative numerator (-3/4), and the latter is the conventional way to write it.