Question: how to calculate compound interest with a calculator?
Answer: Calculate Accrued Amount (Principal + Interest) A = P(1 + r)t
Calculate Principal Amount, solve for P. P = A / (1 + r)t
Calculate rate of interest in decimal, solve for r. r = (A/P)1/t - 1.
Calculate rate of interest in percent. ... 
Calculate time, solve for t.