Enter your data in a single column or row
Use the formula `=STDEV.S(range)/SQRT(COUNT(range))` for a sample standard error
Replace `range` with your actual cell range, such as `A1:A10`
Use `=STDEV.P(range)/SQRT(COUNT(range))` if you need the population standard error
Press Enter to get the result
If needed, calculate the sample size with `=COUNT(range)`
If needed, calculate the standard deviation with `=STDEV.S(range)`