Quarterly Compound Interest Calculator
Interest added every three months — 4 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 | $1,048 | $17,048 |
| 2 | $17,048 | $6,000 | $1,629 | $24,676 |
| 3 | $24,676 | $6,000 | $2,258 | $32,934 |
| 4 | $32,934 | $6,000 | $2,938 | $41,872 |
| 5 | $41,872 | $6,000 | $3,675 | $51,547 |
| 6 | $51,547 | $6,000 | $4,473 | $62,020 |
| 7 | $62,020 | $6,000 | $5,336 | $73,356 |
| 8 | $73,356 | $6,000 | $6,270 | $85,626 |
| 9 | $85,626 | $6,000 | $7,282 | $98,908 |
| 10 | $98,908 | $6,000 | $8,377 | $113,285 |
| 11 | $113,285 | $6,000 | $9,562 | $128,846 |
| 12 | $128,846 | $6,000 | $10,845 | $145,691 |
| 13 | $145,691 | $6,000 | $12,233 | $163,924 |
| 14 | $163,924 | $6,000 | $13,736 | $183,660 |
| 15 | $183,660 | $6,000 | $15,363 | $205,023 |
| 16 | $205,023 | $6,000 | $17,124 | $228,147 |
| 17 | $228,147 | $6,000 | $19,030 | $253,177 |
| 18 | $253,177 | $6,000 | $21,093 | $280,271 |
| 19 | $280,271 | $6,000 | $23,327 | $309,597 |
| 20 | $309,597 | $6,000 | $25,744 | $341,342 |
| 21 | $341,342 | $6,000 | $28,361 | $375,702 |
| 22 | $375,702 | $6,000 | $31,193 | $412,896 |
| 23 | $412,896 | $6,000 | $34,259 | $453,155 |
| 24 | $453,155 | $6,000 | $37,578 | $496,733 |
| 25 | $496,733 | $6,000 | $41,170 | $543,904 |
| 26 | $543,904 | $6,000 | $45,059 | $594,962 |
| 27 | $594,962 | $6,000 | $49,267 | $650,230 |
| 28 | $650,230 | $6,000 | $53,823 | $710,053 |
| 29 | $710,053 | $6,000 | $58,755 | $774,807 |
| 30 | $774,807 | $6,000 | $64,092 | $844,900 |
| Total | — | $190,000 | $654,900 | $844,900 |
How much does quarterly compounding really change?
Quarterly is only marginally behind monthly. Over a decade at typical rates the gap is a fraction of a percent — not something to switch products over.
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 (this page) | 4 | $16,436.19 | +$147.25 |
| Annual | 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 quarterly compounding
Some certificates of deposit, bonds, and dividend-paying instruments settle quarterly. Company pension statements are often quoted on a quarterly basis.
Other compounding frequencies
Related Calculators
Frequently Asked Questions
- Interest is calculated and added to your balance every three months — 4 times a year. From the next period onward you earn interest on that interest too. Some certificates of deposit, bonds, and dividend-paying instruments settle quarterly. Company pension statements are often quoted on a quarterly basis.