排列与组合计算器

使用方法

1. 1
   填写各项

   输入数字或选择所需选项。

2. 2
   查看结果

   更改任何值时，答案会立即更新。

3. 3
   使用结果

   复制结果或记下来。不会向任何地方发送任何内容。

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.

计算示例

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.

获得最佳结果的提示

在相信结果之前先检查每一个输入项，因为一个错误的数字就会改变整个答案。请使用工资单、账单、证书或合同上的准确数字，并记下计算日期。税率、门槛和规则会不时变化，因此对于税费和法律事务，请将结果视为估算，并与本页注明的官方来源核对。您可以尝试任意多个方案；不会保存或发送任何内容，刷新页面会清空输入。