Annual Compound Interest Calculator
Interest added once a year — 1 times a year. Adjust the inputs to see the year-by-year effect.
Year-by-Year Breakdown
| Year | Starting Balance | Contributions | Interest Earned | Ending Balance |
|---|---|---|---|---|
| 1 | $10,000 | $6,000 | $1,017 | $17,017 |
| 2 | $17,017 | $6,000 | $1,578 | $24,595 |
| 3 | $24,595 | $6,000 | $2,185 | $32,780 |
| 4 | $32,780 | $6,000 | $2,839 | $41,619 |
| 5 | $41,619 | $6,000 | $3,546 | $51,166 |
| 6 | $51,166 | $6,000 | $4,310 | $61,476 |
| 7 | $61,476 | $6,000 | $5,135 | $72,611 |
| 8 | $72,611 | $6,000 | $6,026 | $84,637 |
| 9 | $84,637 | $6,000 | $6,988 | $97,624 |
| 10 | $97,624 | $6,000 | $8,027 | $111,651 |
| 11 | $111,651 | $6,000 | $9,149 | $126,800 |
| 12 | $126,800 | $6,000 | $10,361 | $143,161 |
| 13 | $143,161 | $6,000 | $11,670 | $160,831 |
| 14 | $160,831 | $6,000 | $13,083 | $179,915 |
| 15 | $179,915 | $6,000 | $14,610 | $200,525 |
| 16 | $200,525 | $6,000 | $16,259 | $222,784 |
| 17 | $222,784 | $6,000 | $18,040 | $246,823 |
| 18 | $246,823 | $6,000 | $19,963 | $272,786 |
| 19 | $272,786 | $6,000 | $22,040 | $300,826 |
| 20 | $300,826 | $6,000 | $24,283 | $331,109 |
| 21 | $331,109 | $6,000 | $26,706 | $363,815 |
| 22 | $363,815 | $6,000 | $29,322 | $399,137 |
| 23 | $399,137 | $6,000 | $32,148 | $437,285 |
| 24 | $437,285 | $6,000 | $35,200 | $478,485 |
| 25 | $478,485 | $6,000 | $38,496 | $522,980 |
| 26 | $522,980 | $6,000 | $42,055 | $571,036 |
| 27 | $571,036 | $6,000 | $45,900 | $622,935 |
| 28 | $622,935 | $6,000 | $50,052 | $678,987 |
| 29 | $678,987 | $6,000 | $54,536 | $739,523 |
| 30 | $739,523 | $6,000 | $59,379 | $804,902 |
| Total | — | $190,000 | $614,902 | $804,902 |
How much does annual compounding really change?
Annual compounding is the floor, not a trap. It produces the most conservative figure of the five, which makes it a reasonable choice when you want a deliberately cautious projection.
The table below holds everything constant — $10,000 at 5% for 10 years, no contributions — and varies only the compounding cadence.
| Frequency | Times / year | Final balance | vs annual |
|---|---|---|---|
| Daily | 365 | $16,486.65 | +$197.70 |
| Weekly | 52 | $16,483.25 | +$194.31 |
| Monthly | 12 | $16,470.09 | +$181.15 |
| Quarterly | 4 | $16,436.19 | +$147.25 |
| Annual (this page) | 1 | $16,288.95 | — |
The spread across every cadence is $197.70 — under 1.2% of the balance. Raising the rate by a quarter of a point, or adding a small monthly contribution, moves the result far more than any change of frequency. Try it in the calculator above.
Where you meet annual compounding
Textbook examples, some fixed-term bonds, and most long-horizon "what if" projections quoted in the press. It is the simplest case and the easiest to check by hand.
Other compounding frequencies
Related Calculators
Frequently Asked Questions
- Interest is calculated and added to your balance once a year — 1 times a year. From the next period onward you earn interest on that interest too. Textbook examples, some fixed-term bonds, and most long-horizon "what if" projections quoted in the press. It is the simplest case and the easiest to check by hand.