Estimate:If you estimate a quantity or value,you make an approximate judgment or calculation of it.
Evaluate:If you evaluate something or someone,you consider them in order to make a judgment about them,for example about how good or bad they are.
estimate 用来判断事物的量和价值,evaluate用来判断人或物的好坏.个人理解是estimate更适用于客观估计,一般都要给出量值；evaluate是主观的评估,只是判断好坏.honestly,i can not catch essential differences.thank you all the same