system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: the difference between variance and standard deviation

Thanks to everyone for the guidance. It may not seem like much to some of you, but it has been a huge help to someone who is getting off the ground in this area.
gpt
Standard deviation is the square root of variance.

Variance is used in calculations because it makes a lot of maths easier - a lot of things like error propagation are done in quadrature (i.e. on the square of the values). 

Standard deviation has the big advantage that it's got the same units as the original data so you can more easily interpret what it means.