Compound Interest Calculator

How it's calculated

A = P × (1 + r ÷ n)^(n × t)   (continuously: A = P × e^(r × t))
Monthly additions C: + C × ((1 + i)^m − 1) ÷ i, i = the equivalent monthly rate

Compound interest adds each period's interest to the balance, so later interest is earned on earlier interest. More frequent compounding raises the effective yearly rate a little. The rate is assumed constant; real savings and investment returns vary.