How to Find Standard Deviation on Calculator
This free how to find standard deviation on calculator gives you an answer in a couple of seconds, and shows the full working underneath so you can check it rather than take it on trust. Change any value and the result updates immediately. Nothing is stored, nothing is sent anywhere, and there is no sign-up.
Standard deviation
2.1381
- Count
- 8
- Mean
- 5
- Median
- 4.5
- Variance
- 4.5714
- Range
- 2 to 9
- Outlier bounds (1.5 × IQR)
- 1.75 to 7.75
How this is calculated
- 1
Find the mean
x̄ = Σx ÷ n
x̄ = 40 ÷ 8
= 5
- 2
Sum the squared deviations
SS = Σ(x − x̄)²
SS = Σ(x − 5)²
= 32
- 3
Divide by n − 1 to get the variance
s² = SS ÷ (n − 1)
s² = 32 ÷ 7
= 4.5714
- 4
Take the square root
s = √s²
s = √4.5714
= 2.1381
How to use this how to find standard deviation on calculator
- Fill in your values. Every field starts with a sensible default, so you can change one number at a time and watch what it does to the result.
- Read the result. The headline figure sits in the pink box, with supporting numbers listed below it.
- Check the working. The breakdown shows each formula and the same formula with your numbers substituted in, so you can follow the method or reproduce it by hand.