EcoEng

Calculates Economy Engineering useful stuff by the formulas:
Given i = interest, n = # of installments, e = initial installment and p = following installments value:
interest accrued = (1+i)^n

A/G = (1/i) - (n/(interestAccrued - 1))
Va/Vf = 1 / interestAccrued
Va/A = ((interestAccrued - 1)/(i * interestAccrued));

Va = Va/A * installmentValue; + initial installment

Same as the paid version. Paid version has no extra feature, only supports the developer.