Investment Calculator
Growth of a starting amount plus regular contributions.
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Enter your numbers to see the result.
This investment calculator shows how money can grow when you invest a starting amount and keep adding to it every month. Enter your initial investment, monthly contribution, expected annual return and number of years. You’ll see the ending balance, how much came from your contributions versus earnings, the value in today’s dollars and a year-by-year table.
What is a Investment Calculator?
An investment calculator projects how money grows when returns compound over time. Most people don’t invest one lump sum and walk away; they start with something and add a little every month. That habit, called dollar-cost averaging, means you buy more shares when prices are low and fewer when they’re high.
This investment calculator handles both the starting amount and regular contributions, shows how much of the final balance came from your own money versus market growth, and converts the result into today’s dollars so you can judge what it will actually buy.
How does the Investment Calculator work?
The starting amount grows at the monthly equivalent of your expected return. Each monthly contribution is added at the start or end of the month and grows for the months that remain.
The calculator adds the two parts together and builds a year-by-year table. If you enter inflation, it also divides the ending balance by the inflation factor.
How to use the Investment Calculator step by step
- Enter your initial investment.
- Enter your monthly contribution.
- Enter an expected annual return.
- Choose the number of years and when you contribute.
- Add inflation to see today’s dollars.
- Review the balance and download the yearly table.
Investment Calculator example with real numbers
You open a brokerage account with $5,000, invest $100 every month in a broad index fund and expect a 7% average annual return over 30 years.
| Example input | Value |
|---|---|
| Initial investment | $5,000 |
| Monthly contribution | $100 |
| Expected annual return | 7% |
| Years | 30 years |
| Contribute at the | End of each month |
| Inflation (optional) | 3% |
| Example output | Value |
|---|---|
| Balance after 30 years | $162,580 |
| Total contributions | $41,000 |
| Investment earnings | $121,580 |
| Earnings share of balance | 74.8% |
| Value in today's dollars | $66,981 |
The investment calculator estimates a balance of $162,580. You contribute $41,000, and $121,580 comes from growth. After 3% inflation, that’s about $66,981 in today’s dollars.
Key features of this Investment Calculator
- Starting amount plus monthly contributions
- Start- or end-of-month timing
- Contributions vs earnings split
- Inflation-adjusted value
- Yearly table with CSV download
Who should use the Investment Calculator?
Who is this Investment Calculator for?
- New investors starting with small monthly amounts
- Parents investing for a child
- Anyone comparing savings with investing
- Teachers explaining compounding
Practical use cases
- Seeing what $100 a month becomes in 30 years
- Comparing 5% and 8% return assumptions
- Checking the impact of starting 10 years earlier
- Planning a taxable brokerage account
Key benefits
- Motivating: see compounding at work.
- Realistic: today’s-dollars view.
- Flexible: any mix of lump sum and monthly saving.
- Portable: download the table.
Tips for better results
- Use a conservative return; long-run stock market averages are not guaranteed.
- Automate contributions so they happen every month.
- Use tax-advantaged accounts like a 401(k) or IRA first if you’re eligible.
- Keep fees low; a 1% fee can cost a large share of long-term growth.
Common mistakes to avoid
- Assuming the same return every year.
- Ignoring fees and taxes.
- Stopping contributions during market drops.
- Investing money you’ll need within a few years in stocks.
Limitations of this Investment Calculator
- It assumes a constant return.
- It does not include taxes or fund fees.
- Contributions are assumed to be the same every month.
Investment Calculator vs other ways to calculate
| Tool | Lump sum | Monthly contributions | Tax treatment |
|---|---|---|---|
| Investment calculator | Yes | Yes | Not included |
| 401(k) calculator | Balance | % of salary + match | Pre-tax |
| Roth IRA calculator | Balance | Yearly limit | Tax-free growth |
| CD calculator | Yes | No | Interest taxed yearly |
Investor.gov, run by the SEC, offers a compound interest calculator with similar inputs. For workplace plans with a match, use the 401(k) calculator.
Privacy and data handling
This Investment Calculator runs entirely in your browser. The numbers you type are not sent to Qorico or stored on any server, and nothing is saved after you close the page. The Copy and Download buttons create the result on your own device. If the page has analytics turned on, it may count that a calculation happened, but it does not record the values you entered.
Investment Calculator FAQs
What is dollar-cost averaging?
Investing a fixed amount at regular intervals regardless of price. It spreads purchases over time and builds a habit.
How much will $100 a month grow?
At a 7% average annual return, $100 a month grows to about $122,000 in 30 years, of which $36,000 is your contributions.
What is the average stock market return?
Over long periods, the S&P 500 has averaged roughly 10% a year before inflation, but returns vary widely from year to year and are not guaranteed.
Is dollar-cost averaging better than lump-sum investing?
Lump-sum investing has often done better because money is invested sooner, but dollar-cost averaging reduces the risk of investing everything at a peak.
Should I use start or end of month?
If your contribution goes in right after payday, start of month is closer. The difference is small over long periods.
Does this include taxes?
No. Taxes depend on the account type: taxable, traditional or Roth.
Related tools
Sources and references
We checked the method and the current figures used in this Investment Calculator against these official and primary sources:
Written and reviewed by the Qorico Team
