Enter two whole numbers. For example, 12 and 18 give GCD 6 and LCM 36.
Whole numbers only (1, 2, 3 …)
Whole numbers only (1, 2, 3 …)
Result
LCM 36 · GCD 6
GCD of 12 and 18 is 6; LCM is 36.
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| What | Formula | Example |
|---|---|---|
| GCD | Euclid’s method | GCD(12, 18) = 6 |
| LCM | a × b ÷ GCD | 12 × 18 ÷ 6 = 36 |
12 and 18: GCD 6, LCM 36.
5 and 7: GCD 1, LCM 35.
LCM aligns denominators when adding fractions; GCD simplifies them. LCM also tells when repeating events coincide.
GCD is the largest number dividing both; LCM is the smallest multiple of both. For 12 and 18, GCD is 6 and LCM is 36.
LCM = (a × b) ÷ GCD. GCD comes from Euclid's method with remainders.
No — enter positive whole numbers only.
For two primes the GCD is 1 and the LCM is their product. For 5 and 7: GCD 1, LCM 35.
Divide the numerator and denominator by the GCD. For 12/18 the GCD is 6, so it simplifies to 2/3.
lcm gcd finder · least common multiple
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