How this calculation works
Neither number needs to be prime. For example, 8 and 9 are coprime although both are composite.
THE FORMULA
Two numbers are coprime when gcd(a,b) = 1A worked example
14 and 25 share no prime factors, so they are coprime.
Good to know
Two composite numbers can still be coprime.
Reference: NIST DLMF, Functions of Number Theory (opens in a new tab) ↗
Read the result
Check whether the only common positive divisor is 1.
The primary result is labeled “Coprime?”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
Two composite numbers can still be coprime.
For a related exercise, try the greatest common divisor.
A few questions, answered
How can I check the default inputs by hand?
14 and 25 share no prime factors, so they are coprime.
Which rule does this calculator apply?
Two numbers are coprime when gcd(a,b) = 1