Sponsored
Compound Interest Calculator
Free compound interest calculator. Enter your starting amount, monthly contributions, annual interest rate, compounding frequency, and time period to see your final balance, total contributions, total interest earned, and a year-by-year breakdown.
Initial deposit / principal
Added each month (can be 0)
Expected annual return
1 to 50 years
Final Amount
£144,572.72
Total Contributions
£58,000.00
Total Interest Earned
£86,572.72
Effective annual rate: 7.229%
Year-by-Year Breakdown
| Year | Balance | Contributions | Interest |
|---|---|---|---|
| 1 | £13,201.42 | £2,400.00 | £801.42 |
| 2 | £16,634.27 | £2,400.00 | £1,032.85 |
| 3 | £20,315.28 | £2,400.00 | £1,281.01 |
| 4 | £24,262.39 | £2,400.00 | £1,547.11 |
| 5 | £28,494.83 | £2,400.00 | £1,832.45 |
| 6 | £33,033.24 | £2,400.00 | £2,138.41 |
| 7 | £37,899.74 | £2,400.00 | £2,466.49 |
| 8 | £43,118.03 | £2,400.00 | £2,818.29 |
| 9 | £48,713.55 | £2,400.00 | £3,195.52 |
| 10 | £54,713.58 | £2,400.00 | £3,600.02 |
| 11 | £61,147.34 | £2,400.00 | £4,033.77 |
| 12 | £68,046.20 | £2,400.00 | £4,498.86 |
| 13 | £75,443.79 | £2,400.00 | £4,997.58 |
| 14 | £83,376.14 | £2,400.00 | £5,532.35 |
| 15 | £91,881.93 | £2,400.00 | £6,105.79 |
| 16 | £101,002.60 | £2,400.00 | £6,720.67 |
| 17 | £110,782.60 | £2,400.00 | £7,380.00 |
| 18 | £121,269.60 | £2,400.00 | £8,087.00 |
| 19 | £132,514.70 | £2,400.00 | £8,845.11 |
| 20 | £144,572.72 | £2,400.00 | £9,658.02 |
Sponsored
Frequently Asked Questions
What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which is calculated only on the principal, compound interest grows exponentially over time. The more frequently interest compounds and the longer you hold an investment, the more your money grows.
How often should interest compound?
Daily compounding produces slightly more growth than monthly, which produces more than annual compounding. For a 7% rate over 20 years, the difference between daily and annual compounding is roughly 0.2% in total return. Monthly compounding is the most common for savings accounts and investments.
What is the Rule of 72?
The Rule of 72 is a quick mental shortcut to estimate how long it takes an investment to double. Divide 72 by the annual interest rate: at 6%, money doubles in about 12 years (72 / 6 = 12). At 9%, it doubles in about 8 years. It works best for rates between 4% and 15%.
How much should I save per month?
It depends on your goal, time horizon, and expected return. As a rough guide, if you want to reach a target amount, use this calculator in reverse: enter your target as the final goal and adjust the monthly contribution until the result matches. Starting early makes a far bigger difference than the amount you contribute.
Learn More
Get a free tool tip every week
One practical tip, one featured tool, every Tuesday. Takes 90 seconds to read. No spam, unsubscribe any time.