CalcQuick · Interest
Compound Interest Calculator with Contributions
Enter the starting principal, annual rate and time period. Keep monthly contributions at zero for the original lump-sum calculation, or add regular deposits and choose when they are made.
Reviewed and updated:Year-by-Year Breakdown
| Year | Contributions | Interest | Balance |
|---|---|---|---|
| 1 | $10,000.00 | $500.00 | $10,500.00 |
| 2 | $10,000.00 | $1,025.00 | $11,025.00 |
| 3 | $10,000.00 | $1,576.25 | $11,576.25 |
| 4 | $10,000.00 | $2,155.06 | $12,155.06 |
| 5 | $10,000.00 | $2,762.82 | $12,762.82 |
| 6 | $10,000.00 | $3,400.96 | $13,400.96 |
| 7 | $10,000.00 | $4,071.00 | $14,071.00 |
| 8 | $10,000.00 | $4,774.55 | $14,774.55 |
| 9 | $10,000.00 | $5,513.28 | $15,513.28 |
| 10 | $10,000.00 | $6,288.95 | $16,288.95 |
01
How to use this calculator
- Enter your values using the units shown.
- Review the result, which updates instantly.
- Check the formula and assumptions before using the number for a decision.
02
Formula and assumptions
Simple interest: A = P(1 + rt). Compound interest: A = P(1 + r/n)^(nt). Monthly deposits use the equivalent monthly rate for the selected compounding frequency; continuous compounding uses e^(rt).
03
Worked example
$10,000 at 5% for 10 years, compounded monthly with no further deposits, grows to about $16,470. Adding $100 at each month-end raises the projection to about $31,998.
CalcQuick
Sources and scope
These references support the formula or category guidance. CalcQuick remains responsible for the calculator implementation.
- Investor.gov Compound Interest CalculatorU.S. Securities and Exchange Commission
FAQ
Frequently asked questions
What does compounding frequency change?
It controls how often interest is added. At the same nominal annual rate, more frequent compounding gives a slightly higher result.
When is the monthly contribution added?
You can choose the beginning or end of each month. Beginning-of-month contributions receive one additional month of growth.
What does the Interest column in the yearly table show?
It shows the balance minus the starting principal and all contributions made through that year.