换手率也称周转率，指在一定时间内市场中股票转手买卖的频率，其数值为某只股票的累计成交量与其流通股本之间的比率，是反映股票流通性强弱的指标之一，可以有效地帮助投资者识别一只股票的活跃度。

换手率的英文可以用turnover rate或turnover ratio来表示：

The turnover ratio of a stock is a measure of sellers versus buyers of a particular stock. It is calculated by dividing the daily volume of a stock by the "float" of a stock, which is the number of shares available for sale by the general trading public.

换手率=某一段时期内的成交量/流通股本x100%

例如，某只股票在一个月内成交了2000万股，而该股票的流通股为1亿股，则该投票在者个月的换手率为20%。在中国，股票分为可在二级市场流通的社会公众股和不可在二级市场流通的国家股和法人股两个部分，一般只可对可流通部分的股票计算换手率，以更真实和准确地反映出股票的流通性。

此外，turnover rate在企业中，还可以表示人员流动率：

Turnover rate is defined as the percentage of employees who left a company over a certain period of time. It's often described in relation to employee retention rate, which measures the number of employees retained from the beginning of a set period until the end.