Compound Interest Calculator
Calculate compound interest growth on savings or investments. See how your money compounds monthly, quarterly or yearly, with a full balance schedule.
How it's calculated
Balance grows by 5.5% per year, compounded monthly, plus a £200 monthly contribution. This uses a constant rate and does not account for inflation or taxes.
Frequently asked questions
How do I calculate compound interest?
Use the formula A = P(1 + r/n)^(nt), where P is your starting amount, r is the annual rate, n is how often interest compounds per year, and t is the years. This calculator does that work for you, adding any monthly contributions automatically.
What is the difference between compound and simple interest?
Simple interest is paid only on the original amount. Compound interest is paid on the original amount plus any interest already earned, so your money grows faster over time.
Related calculators
Emergency Fund Calculator
Work out how much you should keep in an emergency fund and how long it takes to build it with regular contributions.
Savings Goal Calculator
Find out how much to save each month to reach a savings goal by a target date, with or without interest.
Mortgage Calculator
Estimate monthly mortgage payments, total interest and a full amortization schedule. Compare rates, terms and down payments instantly.
Rent vs Buy Calculator
Compare renting vs buying a home over your chosen time horizon, factoring in purchase costs, maintenance, rent growth and investment returns.