🔢 Math Calculator
GCF Calculator
Find the Greatest Common Factor (GCF) of two or more numbers instantly. Shows step-by-step solutions using both the Euclidean algorithm and prime factorization methods.
GCF (Greatest Common Factor)
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Enter 2 or more numbers. Example: 12, 18, 24
GCF of all numbers
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Find both GCF and LCM of two numbers simultaneously
GCF
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LCM
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Relationship: GCF × LCM
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📖 How to Use the GCF Calculator
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Two Numbers tab — enter any two whole numbers to find their GCF instantly with full working.
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Multiple Numbers tab — enter 3 or more comma-separated numbers to find the GCF of the entire set.
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GCF & LCM tab — find both the Greatest Common Factor and Least Common Multiple at the same time.
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Tap Show Steps to see the full Euclidean algorithm and prime factorization methods.
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Copy the result with one tap or Reset to start a fresh calculation.
⚡ Why Use Our GCF Calculator?
GCF
3 Modes
Two numbers, multiple numbers, and combined GCF + LCM.
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Step-by-Step
Full Euclidean algorithm and prime factorization shown.
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Real-Time
Results update instantly as you type numbers.
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Mobile-Friendly
Works on all phones, tablets, and desktops.
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Multiple Numbers
Find GCF of 3, 4, 5 or more numbers at once.
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100% Free
No sign-up — completely free forever.
❓ Frequently Asked Questions
The GCF (also called GCD or HCF) is the largest positive integer that divides all the given numbers without leaving a remainder. For example, the GCF of 48 and 18 is 6, because 6 is the largest number that divides both evenly.
Divide the larger number by the smaller. Take the remainder and divide the previous smaller number by it. Repeat until remainder is 0. The last non-zero remainder is the GCF. Example: GCF(48,18) → 48÷18=2 R12 → 18÷12=1 R6 → 12÷6=2 R0 → GCF=6.
For any two numbers a and b: GCF(a,b) × LCM(a,b) = a × b. This means once you know the GCF, you can find the LCM using: LCM = (a × b) ÷ GCF. Use our GCF & LCM tab to see both values at once.