Greatest common factor
GCF = 6
Formula: GCF(a, b) = GCF(b, a mod b)
12: 1, 2, 3, 4, 6, 12
18: 1, 2, 3, 6, 9, 18
Find the greatest common factor quickly and use it to simplify fractions and compare shared factors.
Runs in your browser · No data stored · No signup
Find the greatest common factor quickly and use it to simplify fractions and compare shared factors.
Greatest common factor
GCF = 6
Formula: GCF(a, b) = GCF(b, a mod b)
12: 1, 2, 3, 4, 6, 12
18: 1, 2, 3, 6, 9, 18
Find the greatest common factor of two or more integers using the Euclidean algorithm and factor-method explanations. Runs locally in your browser when supported—no upload required for normal use. Designed for quick everyday tasks with clear, copy-friendly output.
Load GCF Calculator on EverydayTools—no account required.
Type, paste, or upload depending on what the tool accepts.
Results update in your browser for typical use cases.
Copy the output or use download/export when available.
Common real-world scenarios where this tool saves time.
Find the greatest common factor quickly and use it to simplify fractions and compare shared factors.
Use when you want results without uploading files—local browser processing when the tool supports it.
Open GCF Calculator in any modern browser for quick checks with copy-friendly output.
How this EverydayTools page compares for typical use.
| Aspect | EverydayTools | Typical alternative |
|---|---|---|
| Cost | Free | Paid apps or trials |
| Privacy | Browser-local when supported | Often requires cloud upload |
| Signup | Not required | Often required |
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The GCF (GCD) is the largest positive integer that divides every input number without remainder. Example: GCF(12, 18) = 6.
GCF is the largest shared divisor; LCM is the smallest shared multiple. Use GCF to simplify fractions; LCM helps find common denominators.
Find the greatest common factor quickly and use it to simplify fractions and compare shared factors.
GCF Calculator (/gcf-calculator) runs in your browser when supported—inputs are not uploaded to EverydayTools servers.
Yes—GCF Calculator is designed for modern mobile and desktop browsers without installing an app.
GCF Calculator keeps typical inputs on your device—nothing is uploaded to EverydayTools servers for core calculations.
More free tools for the same workflow.
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Reviewed by EverydayTools Editorial Team on 2026-05-28.