FAQ
What is the difference between permutation and combination?
Permutation considers order, combination does not. For example, selecting 2 from A, B, C: permutations are AB, BA, AC, CA, BC, CB (6 total); combinations are AB, AC, BC (3 total). Formula: P(n,r)=n!/(n-r)!, C(n,r)=n!/(r!(n-r)!)
What is permutation with repetition?
Permutation with repetition allows the same element to be selected multiple times. The formula is n^r. For example, a 4-digit PIN has 10⁴=10,000 possible combinations. This is useful for password and key space calculations.
What is a factorial n!?
Factorial n! = n×(n-1)×(n-2)×...×2×1. For example, 5!=120. By convention, 0!=1. Factorials grow extremely fast: 20!≈2.4×10¹⁸. This tool uses BigInt for large number calculations.
Where are permutations and combinations used?
Common use cases: 1) Probability theory event counting; 2) Cryptography key space calculation; 3) Lottery probability; 4) Scheduling and roster planning; 5) Tournament arrangements; 6) Sampling survey design.
❓ Frequently Asked Questions
Does Permutation & Combination Calculator upload my data to a server?
No. Permutation & Combination Calculator uses client-side processing — everything runs in your browser. Your data never leaves your device, and the tool works even without an internet connection.
Is my data safe when using Permutation & Combination Calculator?
Absolutely. All processing happens locally in your browser. No data is sent to any server, so there's zero risk of data leaks. Your information stays completely under your control.
Is Permutation & Combination Calculator free to use?
Yes, Permutation & Combination Calculator is completely free to use. No registration or login required — all features are available immediately.
Can I use Permutation & Combination Calculator on my phone?
Yes. Permutation & Combination Calculator is fully responsive and works on phones, tablets, and desktops. The interface adapts automatically to your screen size.