GCD (HCF) Calculator
Finds the highest common factor.
Result
- Greatest common divisor
- 12
How to use the gcd (hcf) calculator
- Enter the numbers (separated by commas).
- The results update as you type, or press Calculate.
- Read the greatest common divisor first, then the supporting figures below it.
Formula
Euclid's algorithm: gcd(a, b) = gcd(b, a mod b).
Worked example
For example, with these inputs:
- Numbers (separated by commas): 24, 36, 60
the calculator returns:
- Greatest common divisor: 12
Background
Calculators are best used to check working rather than replace it, especially for exams where method marks count. Work the problem by hand first, then confirm with the calculator.
A quick mental estimate before calculating is a powerful check. If a room's floor area comes out at 4,000 square metres or a percentage comes out above 100% when it should not, you know to look again.
Frequently asked questions
How does the gcd (hcf) calculator work?
It applies this formula: Euclid's algorithm: gcd(a, b) = gcd(b, a mod b).
Can I use any units?
Yes, as long as every input uses the same unit. The answer will be in that unit (squared for areas, cubed for volumes).