GCF for 12, 18 and 30

"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
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What's the Greatest Common Factor (GCF) of 12, 18 and 30?

Answer

GCF of 12, 18 and 30 is
6

Common factors: 1, 2, 3, 6

6 divides all three: 12 ÷ 6 = 2, 18 ÷ 6 = 3, 30 ÷ 6 = 5 — and 2, 3 and 5 have no factor but 1 common to all of them, so no larger number divides all three.

12 = 22 × 3

18 = 2 × 32

30 = 2 × 3 × 5

Prime121830Lowest power
222222
333233
5——5—

— = power 0: the prime is not a factor of this number, so it cannot be in the GCF.

GCF = 2 × 3 = 6

See Also

GCF Table

1st2nd3rdGCF
1215183
1216182
1217181
1218186
1218191
1218202
1218213
1218222
1218231
1218246
1218251
1218262
1218273
1218282
1218291
1218306
1218311
1218322
1218333
1218342
1218351
1218366
1218371
1218382
1218393
1218402
1218411
1218426
1218431
1218442

FAQ

What's the Greatest Common Factor (GCF) of 12, 18 and 30?

GCF of 12, 18 and 30 is 6

What prime factors do 12, 18 and 30 share?

All three factorizations contain 2 × 3, and multiplying those shared primes gives 6 — exactly the greatest common factor.

Can you get the GCF of 12, 18 and 30 two numbers at a time?

Yes. The GCF of 12 and 18 is 6, and the GCF of 6 and 30 is 6 — the same answer, because the greatest common factor is associative and does not depend on the order of the three numbers.

How does the GCF simplify the ratio 12 : 18 : 30?

Divide every term by the GCF 6: 12 ÷ 6 = 2, 18 ÷ 6 = 3 and 30 ÷ 6 = 5. So 12 : 18 : 30 in lowest terms is 2 : 3 : 5, and no whole number other than 1 divides all three of those.