Make the numbers
make sense.
Common factors, shared multiples, and a different way to write numbers.
Three useful tools. Clear working. No fuss.
Choose a math calculator
HCF Calculator
Find the largest factor your numbers share, with the working shown.
Open calculatorLCM Calculator
Find the smallest shared multiple of two or more numbers.
Open calculatorRoman Converter
From numbers to Roman numerals. And back again.
Open calculatorWhich calculator do I need?
Use the highest common factor calculator to find the largest divisor shared by your integers. Use the least common multiple calculator to find the smallest positive multiple they share. The Roman number converter translates between ordinary decimal numbers and Roman numerals.
Searching for a “highest common denominator calculator” or “largest common denominator calculator”? Those phrases are often used when someone means a common factor or divisor. For adding fractions, however, the least common denominator is a different calculation: find the LCM of the denominators. There is no highest common multiple of positive integers; their shared multiples keep increasing.