Compound growth.
One month at a time.
See how your starting amount, regular saving, and time work together. Explore simple or compound interest.
Your numbers
ILLUSTRATIVE EXAMPLEPlanning estimate: every month is 1/12 of a year. Actual dates and leap years are not used. Bank maturity amounts for fixed deposits (FDs) or certificates of deposit (CDs) may differ.
USD • Amounts up to $100,000,000.00 (100 million US dollars). Up to 2 decimal places. Valid Indian or international commas are accepted. Rates 0–25%, up to 4 decimals.
Your estimated future balance
USD · International number style
Approximately 17.18 thousand US dollars
You add $13,000.00. The model adds $4,175.24 in growth.
Axis amounts use USD and are rounded. K = thousand; M = million; B = billion; T = trillion. Exact amounts are in View numbers.
Explain this
Some of the final balance is money you added. The rest is growth calculated using your assumed rate. With compound interest, earned interest is added to your money every month. After it is added, it earns interest too. Actual investment results can go down; this model cannot.
Assumptions in this picture
All scenario amounts use USD. International number style. No currency conversion.
- $1,000.00 initially + $100.00 each month for 120 months.
- 5% annual rate (before compounding); compound interest added every month.
- Planning estimate: every month is 1/12 of a year. Actual dates and leap years are not used. Bank maturity amounts for fixed deposits (FDs) or certificates of deposit (CDs) may differ.
- End-of-month deposits.
- Constant nonnegative rate. Taxes, fees, inflation, withdrawals and investment risk excluded.
View numbers
| Month | Starting + added | Growth | Balance |
|---|---|---|---|
| 0 | $1,000.00 | $0.00 | $1,000.00 |
| 12 | $2,200.00 | $79.05 | $2,279.05 |
| 24 | $3,400.00 | $223.53 | $3,623.53 |
| 36 | $4,600.00 | $436.81 | $5,036.81 |
| 48 | $5,800.00 | $722.38 | $6,522.38 |
| 60 | $7,000.00 | $1,083.97 | $8,083.97 |
| 72 | $8,200.00 | $1,525.44 | $9,725.44 |
| 84 | $9,400.00 | $2,050.90 | $11,450.90 |
| 96 | $10,600.00 | $2,664.64 | $13,264.64 |
| 108 | $11,800.00 | $3,371.17 | $15,171.17 |
| 120 | $13,000.00 | $4,175.24 | $17,175.24 |
Printing includes your result and assumptions. Open a comparison, explanation or numbers table to include it.
A picture of one set of assumptions, not a prediction or personal recommendation. See the math behind it.
Growth can build on growth.
USD example. Calculator settings do not convert this article’s amounts.
Start with $1,000, add $100 at each month-end, and assume a 5% nominal annual rate compounded monthly. After 10 years, the model gives $17,175.24: $13,000 you contributed and $4,175.24 in growth.
Simple interest earns interest on your starting money and later deposits. Compound interest also earns interest on earlier interest once it has been added. Choose to add it every month, every 3 months, every 6 months or every year, counting from the start of your scenario.
Deposits at the start of a month earn interest that month. Deposits at the end start earning interest the following month.
Understand compound interest →What this picture leaves out
Returns do not arrive in a smooth line in real life. This model uses a fixed nonnegative rate and leaves out losses, fees, taxes and inflation.
How are days counted for an FD or CD?
Counting days and compounding are separate. Interest can be calculated using actual days but added to the balance only every quarter. Indian fixed-deposit rules also differ: HDFC describes a 365/366-day year, while SBI describes completed quarters plus remaining days on a 365-day basis for reinvestment deposits.
This calculator uses equal-length months. To reproduce the maturity amount of a fixed deposit (FD) or certificate of deposit (CD), you need the deposit and maturity dates and the bank’s product rules, including rounding and tax deductions.
What happens between compounding dates?
The model uses equal-length months and estimates interest each month. The total includes interest earned during an unfinished period; that interest starts earning more interest only when the period ends. Actual account calculations and payment dates may differ.
Is the default rate a recommendation?
No. It is an editable illustration, not a current market rate or a promise.
Why does the rate label matter?
For compound interest, an annual yield already includes compounding; a nominal annual rate does not. Simple interest uses the annual rate divided by 12 and never earns interest on previous interest.