Compound Interest Calculator UK: Monthly Savings Growth
Free UK compound interest calculator: see what a lump sum plus monthly saving grows to, how much is interest, and its value after inflation, year by year.
Compound interest means your interest starts earning interest of its own, so a pot grows slowly at first and then faster each year. Whether the money sits in a savings app, a Cash ISA or a Stocks and Shares ISA, time in the account usually does more than a slightly better rate. Enter a starting sum, what you add each month and an annual rate to see the final balance, how much of it is growth, the year your growth overtakes what you paid in, and what the pot is worth in today's money.
See how your money compounds
How we calculate: the annual rate is treated as an AER, so we convert it to the equivalent monthly rate and compound every month. That gives the same result as an account paying the stated AER, whether it credits interest monthly or yearly. Figures are before tax. Savings interest outside an ISA can be taxable once it passes your Personal Savings Allowance, and investment returns are not guaranteed and can be negative. This is an illustration, not financial advice.
