Compound interest calculator
Project compound growth with deposits at each compounding period end.
Formula
Bnext = B × (1 + annual% / 100 / periods) + deposit
Initial capital = 1,000 · Nominal annual return (%) = 5 · Years = 20 · Periods per year = 12 · Deposit per period = 100
How to use
- Choose the number of compounding periods per year.
- Enter initial capital, deposit per period and years.
- Review balance, interest and year-end totals.
Examples
- 1000 at 10%, annual compounding, 2 years: 1210.
- 1000 plus 100/month for 2 years at 0%: 3400.
Growth schedule
Annual totals
| Year | Contribution | Interest | Closing balance |
|---|---|---|---|
| 1 | 1,200.00 | 79.05 | 2,279.05 |
| 2 | 1,200.00 | 144.49 | 3,623.53 |
| 3 | 1,200.00 | 213.27 | 5,036.81 |
| 4 | 1,200.00 | 285.58 | 6,522.38 |
| 5 | 1,200.00 | 361.58 | 8,083.97 |
| 6 | 1,200.00 | 441.48 | 9,725.44 |
| 7 | 1,200.00 | 525.46 | 11,450.90 |
| 8 | 1,200.00 | 613.74 | 13,264.64 |
| 9 | 1,200.00 | 706.53 | 15,171.17 |
| 10 | 1,200.00 | 804.07 | 17,175.24 |
| 11 | 1,200.00 | 906.60 | 19,281.84 |
| 12 | 1,200.00 | 1,014.38 | 21,496.22 |
| 13 | 1,200.00 | 1,127.67 | 23,823.89 |
| 14 | 1,200.00 | 1,246.76 | 26,270.66 |
| 15 | 1,200.00 | 1,371.94 | 28,842.60 |
| 16 | 1,200.00 | 1,503.53 | 31,546.13 |
| 17 | 1,200.00 | 1,641.85 | 34,387.97 |
| 18 | 1,200.00 | 1,787.24 | 37,375.21 |
| 19 | 1,200.00 | 1,940.07 | 40,515.28 |
| 20 | 1,200.00 | 2,100.72 | 43,816.01 |
Period details
| Period | Contribution | Interest | Closing balance |
|---|---|---|---|
| 1 | 100.00 | 4.17 | 1,104.17 |
| 2 | 100.00 | 4.60 | 1,208.77 |
| 3 | 100.00 | 5.04 | 1,313.80 |
| 4 | 100.00 | 5.47 | 1,419.28 |
| 5 | 100.00 | 5.91 | 1,525.19 |
| 6 | 100.00 | 6.35 | 1,631.55 |
| 7 | 100.00 | 6.80 | 1,738.34 |
| 8 | 100.00 | 7.24 | 1,845.59 |
| 9 | 100.00 | 7.69 | 1,953.28 |
| 10 | 100.00 | 8.14 | 2,061.42 |
| 11 | 100.00 | 8.59 | 2,170.01 |
| 12 | 100.00 | 9.04 | 2,279.05 |
Frequently asked questions
When are contributions added?
At the end of each compounding period, after interest.
Is the rate guaranteed?
No. It is your constant nominal annual assumption; market returns vary.
Are tax, fees and inflation included?
No. All amounts use one currency, before tax, fees and inflation.
Sources
Updated: