排列與組合計算器

使用方法

1. 1
   填寫各項

   輸入數字或選擇所需選項。

2. 2
   檢視結果

   更改任何值時，答案會立即更新。

3. 3
   使用結果

   複製結果或記下來。不會向任何地方傳送任何內容。

About this tool

Enter n, the number of items, and r, how many you choose. You get nPr (permutations), nCr (combinations), n factorial, and the counts when repeats are allowed. Handy for probability, schedules and lottery questions.

When to use it

Work out nPr, nCr and factorials.

Tips

Order matters for permutations, not for combinations.

Privacy

Everything runs in your browser, so your data is not uploaded or stored.

Choosing the right one

Use permutations when the order matters, such as a race podium or a PIN. Use combinations when it does not, such as choosing a committee. nCr is always smaller than or equal to nPr.

計算示例

With the boxes at their starting values (n (total items): 10; r (items chosen): 3), the tool shows: n factorial (n!): 3,628,800; Permutations with repetition (nʳ): 1,000; Combinations with repetition: 220; Permutations nPr: 720; Combinations nCr: 120. Change any box to see your own numbers. The result updates as you type, and nothing leaves your browser.

獲得最佳結果的提示

在相信結果之前先檢查每一個輸入項，因為一個錯誤的數字就會改變整個答案。請使用工資單、賬單、證書或合同上的準確數字，並記下計算日期。稅率、門檻和規則會不時變化，因此對於稅費和法律事務，請將結果視為估算，並與本頁註明的官方來源核對。您可以嘗試任意多個方案；不會儲存或傳送任何內容，重新整理頁面會清空輸入。