HCF (Highest Common Factor), also called GCD (Greatest Common Divisor), is the largest number that divides all given numbers evenly. Example: HCF(12,18) = 6. Calculated using the Euclidean algorithm.
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🔢 HCF / GCD Calculator
Calculate the Highest Common Factor (GCD) of any set of numbers instantly. Uses the efficient Euclidean algorithm. Free for students.
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Free HCF/GCD calculator using the Euclidean algorithm. No sign-up needed.
🤔 How Does This Work?
Uses the Euclidean algorithm: GCD(a,b) = GCD(b, a mod b)
Extends to multiple numbers by iterating pairwise
❓ Frequently Asked Questions
What is HCF/GCD used for?▼
HCF is used to simplify fractions to lowest terms, solve problems about dividing items into equal groups, and in cryptography (RSA encryption relies on properties of GCD).
What is the Euclidean algorithm?▼
An efficient ancient method (300 BC) to find GCD: repeatedly replace the larger number with the remainder of dividing it by the smaller number, until the remainder is 0. The last non-zero remainder is the GCD.
HCF is used to simplify fractions to lowest terms, solve problems about dividing items into equal groups, and in cryptography (RSA encryption relies on properties of GCD).
What is the Euclidean algorithm?▼
An efficient ancient method (300 BC) to find GCD: repeatedly replace the larger number with the remainder of dividing it by the smaller number, until the remainder is 0. The last non-zero remainder is the GCD.