Enter your data into a single column or row
Click an empty cell where you want the result
Type `=STDEV.S(range)` for a sample standard deviation
Type `=STDEV.P(range)` for a population standard deviation
Replace `range` with your data range, such as `A1:A10`
Press Enter
Use `=STDEV.S(A1:A10)` for sample data
Use `=STDEV.P(A1:A10)` for all data in the population
In newer Excel versions, `STDEV.S` and `STDEV.P` are the standard functions
In older Excel versions, use `=STDEV(range)` for sample standard deviation
Check that the selected cells contain only the numbers you want included