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Compound Interest Calculator

Calculate how your investments grow over time with compound interest. See the power of compounding with monthly contributions and different compounding frequencies.

Accurate Results
Works Worldwide
Instant Calculations
£
£
%
Future Value
£32,063
After 10 years
Total Contributed
£22,000
Interest Earned
£10,063
Effective Annual Rate
5.12%
Accounting for compounding frequency
YearStarting BalanceContributionsInterestEnding Balance
1£10,000£1,200£545£11,745
2£11,745£1,200£634£13,578
3£13,578£1,200£728£15,506
4£15,506£1,200£826£17,533
5£17,533£1,200£930£19,663
6£19,663£1,200£1,039£21,902
7£21,902£1,200£1,154£24,255
8£24,255£1,200£1,274£26,729
9£26,729£1,200£1,401£29,329
10£29,329£1,200£1,534£32,063
How This Calculator Works

This calculator uses the compound interest formula: A = P(1 + r/n)^(nt) Where: • A = Final amount • P = Principal (initial investment) • r = Annual interest rate (decimal) • n = Number of times interest compounds per year • t = Time in years For regular contributions, we calculate the future value of an annuity and add it to the compound interest on the principal. The effective annual rate (EAR) shows the true annual return when accounting for compounding frequency.

Frequently Asked Questions

Quick Facts
Rule of 72Years to double = 72 ÷ rate
ISA allowance£20,000/year tax-free
S&P 500 avg return~10% per year
UK inflation target2%
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