Investment Calculator
Find the ending balance for a contribution plan.
Final Balance: $198,290.40
- Starting Amount
- $20,000.00
- Contribution
- $1,000.00 / month
- Return Rate
- 6.000%
- Final Balance
- $198,290.40
- Total Contributions
- $120,000.00
- Total Interest
- $58,290.40
- Term
- 10 years
Contributions vs interest
- Contributions$140,000.0070.6%
- Interest$58,290.4029.4%
Accumulation schedule
| Year | Date | Deposits | Interest | Ending balance |
|---|---|---|---|---|
| 1 | Nov 2027 | $12,000.00 | $1,526.53 | $33,526.53 |
| 2 | Nov 2028 | $12,000.00 | $2,338.12 | $47,864.65 |
| 3 | Nov 2029 | $12,000.00 | $3,198.41 | $63,063.06 |
| 4 | Nov 2030 | $12,000.00 | $4,110.31 | $79,173.37 |
| 5 | Nov 2031 | $12,000.00 | $5,076.93 | $96,250.30 |
| 6 | Nov 2032 | $12,000.00 | $6,101.55 | $114,351.84 |
| 7 | Nov 2033 | $12,000.00 | $7,187.64 | $133,539.48 |
| 8 | Nov 2034 | $12,000.00 | $8,338.90 | $153,878.38 |
| 9 | Nov 2035 | $12,000.00 | $9,559.23 | $175,437.61 |
| 10 | Nov 2036 | $12,000.00 | $10,852.79 | $198,290.40 |
Balance, contributions, and interest over time
- Balance
- Interest
- Contributions
What this investment calculator does
This calculator projects a savings or investment plan over time. It combines a starting amount, recurring contributions, an annual return rate, and compound interest. The five tabs let you solve for a different part of the plan: the ending balance, the contribution amount, the return rate, the starting amount, or the investment length.
The model is useful for comparing scenarios such as increasing a monthly deposit, changing the assumed return, or testing how long a goal may take. It is a planning estimate, not a prediction of market performance.
How to use this calculator
- Choose the tab for the value you want to find.
- Enter the target amount for the tabs that solve toward a goal.
- Enter the starting amount, contribution, annual return rate, and term that are known.
- Choose how often contributions are made, whether they occur at the beginning or end of each period, and how often interest compounds.
- Click Calculate.
The calculator recalculates when you switch tabs, so you can compare the five questions without re-entering the full plan.
Investment growth formula
For a lump sum with periodic compounding:
A = P × (1 + r / n)^(n × t)
P is the starting amount, r is the annual return rate, n is the number of compounding periods per year, and t is the term in years.
Contributions are added on the selected schedule. The calculator converts the annual rate into an effective monthly rate and simulates the balance month by month so that the timing of each deposit is handled consistently.
To reach a target, the calculator searches for the unknown contribution, starting amount, return rate, or number of months. The return-rate solver tests annual rates from 0% to 100%.
What each tab solves
- End Amount: the projected balance after the term.
- Contribute Amount: the monthly or annual contribution needed to reach the target.
- Return Rate: the annual return needed to reach the target with the entered contributions.
- Starting Amount: the initial balance needed today to reach the target.
- Invest Length: the time needed to reach the target with the entered contributions.
What the results include
- Final balance: the projected balance at the end of the term.
- Total contributions: the additional deposits made during the plan, excluding the starting amount.
- Total interest: the final balance minus the starting amount and total contributions.
- Accumulation schedule: yearly contributions, interest, and ending balance.
- Growth chart: balance, cumulative contributions, and cumulative interest.
Assumptions and limitations
Contributions are treated as non-negative amounts and are added at the selected point in each month or year. Annual contributions are made once per plan year. The model does not include taxes, inflation, account fees, or investment losses. Continuous compounding and less common compounding schedules are not included. A solved return rate is limited to the 0% to 100% range.
Frequently asked questions
Is the return rate guaranteed?
No. The return rate is an assumption used to project a balance. Actual investment returns vary and can be negative.
Does the calculator include taxes on investment gains?
No. Taxes, tax-deferred accounts, and tax-advantaged contribution limits are not modeled.
What is the difference between monthly and annual contributions?
A monthly contribution is added every month, while an annual contribution is added once per plan year. The contribution frequency changes the total amount deposited and the amount of time each deposit has to grow.
Why do the tabs give different answers?
Each tab holds the other inputs fixed and solves for one unknown. For example, the Return Rate tab finds the rate that reaches the target using the entered contribution, while the Contribute Amount tab finds the contribution that reaches the same target using the entered rate.
Source
References:
Disclaimer
This calculator is for informational and planning purposes only. It is not financial or investment advice. Investment returns are uncertain, and actual results may differ materially from the projection.