Free calculators and unit converters for general and everyday use.
Our online tools will provide quick answers to your calculation and conversion needs. On this page, you can calculate compound interest with daily/ weekly/ monthly/ quarterly/ half-yearly/ yearly compounding. You can also use this calculator to solve for compounded rate of return, time period and principal.
A = P(1+r/n)nt
CI = A-P
CI = Compounded interest
A = Final amount
P = Principal
t = Time period in years
n = Number of compounding periods per year
r = Interest rate per annum in percentage
You can solve for any variable in compound interest calculation by rearranging the formula as showing in the following examples:-
1. What is the compound interest of 75000 at 7.9% per annum compounded semi-annually in 3 years?
Ans. A = P(1+r/n)nt
We have P=75000, n=2, t=3, r=7.9/100
A = 75000(1 + (7.9 / 100) / 2)6 = 94625.51
Interest = A - P = 94625.51 - 75000 = 19625.51
2. In how many years will a amount double itself at 10% interest rate compounded quarterly?
Ans. t = (log(A/P) / log(1+r/n)) / n
We have n=4, r=10/100, A=2, P=1
t = log(2) / log(1 + 0.1 / 4) / 4 = 7.2 years
3. If interest is compounded daily, find the rate at which an amount doubles itself in 5 years?
Ans. r = ((A/P)1/nt - 1) × n
r = (21/(365×5) - 1) × 365 = 0.1386 = 13.86% per annum