Investment Calculator

Calculate investment growth with compound interest and monthly contributions. Project future value of stocks, bonds, mutual funds, and retirement accounts. See your wealth accumulate over 5, 10, or 30 years.

$
$
%
years
Final Balance
$300,851
after {20} years
Total Contributions
$130,000
Total Interest Earned
$170,851
Growth Breakdown
Contributions (43.2%)Interest (56.8%)
View Year-by-Year Breakdown
YearStart BalanceContributionsInterestEnd Balance
1$10,000$6,000$919$16,919
2$16,919$6,000$1,419$24,339
3$24,339$6,000$1,956$32,294
4$32,294$6,000$2,531$40,825
5$40,825$6,000$3,148$49,973
6$49,973$6,000$3,809$59,782
7$59,782$6,000$4,518$70,299
8$70,299$6,000$5,278$81,578
9$81,578$6,000$6,094$93,671
10$93,671$6,000$6,968$106,639
11$106,639$6,000$7,905$120,544
12$120,544$6,000$8,910$135,455
13$135,455$6,000$9,988$151,443
14$151,443$6,000$11,144$168,587
15$168,587$6,000$12,383$186,971
16$186,971$6,000$13,712$206,683
17$206,683$6,000$15,137$227,820
18$227,820$6,000$16,665$250,486
19$250,486$6,000$18,304$274,790
20$274,790$6,000$20,061$300,851

How to Use the Investment Calculator

  1. 1

    Enter your starting amount

    Type in your initial investment, which is the lump sum you already have or plan to invest right away. This figure serves as the base for all future compounding calculations.
  2. 2

    Set monthly contributions

    Enter the amount you plan to add each month. Even small regular contributions create a powerful compounding effect over time, often exceeding the returns on your initial deposit alone.
  3. 3

    Choose your return rate and time horizon

    Select an expected annual return rate based on your asset mix. A diversified stock portfolio historically averages 7-10% before inflation. Then set the number of years you plan to stay invested.
  4. 4

    Review your projection

    Click calculate to see your projected final balance, total contributions, and total interest earned. Use the year-by-year breakdown table to track how compounding accelerates growth in later years.

Who Benefits from an Investment Calculator?

1

Retirement planners

Estimate whether your current savings rate will meet your retirement goal. Adjust contributions and return assumptions to find the combination that gets you to financial independence on schedule.
2

New investors

See firsthand how starting early, even with small amounts, dramatically outperforms larger contributions made later. The calculator makes the math behind dollar-cost averaging concrete and motivating.
3

Parents saving for education

Project how a 529 plan or regular brokerage account will grow over 10-18 years so you can gauge whether you are on track to cover tuition costs.
4

Side-income earners

Freelancers and gig workers with variable income can model different monthly contribution levels to find a sustainable investing habit that still builds meaningful wealth.

Why Use Investment Calculator?

Understanding how your money grows through compound interest is essential for long-term financial planning. This investment calculator shows you exactly how your initial investment and regular contributions will accumulate over time. Whether you're planning for retirement, saving for a major purchase, or simply wanting to grow your wealth, seeing the projected growth helps you stay motivated and make informed decisions about your investment strategy.

The investment calculator is a free projection tool that models how a lump-sum deposit and recurring contributions grow through compound interest over any time horizon. Enter your initial investment, monthly contribution, expected annual return, and investment period, and the calculator instantly produces a final balance, total interest earned, and a detailed year-by-year breakdown. It supports multiple compounding frequencies, from daily to annual, so you can compare scenarios side by side.

Compound interest is the single most important force in long-term wealth building. Albert Einstein reportedly called it the eighth wonder of the world, and for good reason: a $500 monthly contribution at 8% annual return grows to over $745,000 in 30 years, even though you only contribute $180,000 out of pocket. The remaining $565,000 comes entirely from compounding. This calculator lets you experiment with those numbers so you can set realistic goals. If you want to dig deeper into the compounding math itself, try the Compound Interest Calculator, or use the Retirement Calculator to factor in withdrawal phases and Social Security.

Once you have a growth target, pair this tool with the ROI Calculator to evaluate individual opportunities, the Savings Calculator to plan your emergency fund, or the Net Worth Calculator to track your full financial picture over time.

How It Compares

Most investment calculators available online either hide results behind sign-up walls or push you toward specific brokerage accounts. This calculator runs entirely in your browser with no server uploads, no account required, and no ads interrupting your workflow. You get instant results with a full year-by-year breakdown table, something many competing tools reserve for premium tiers.

Compared to spreadsheet-based projections, the calculator eliminates formula errors and lets you adjust variables in real time. Compared to robo-advisor projections, it gives you complete control over return assumptions without anchoring you to a single platform's asset allocation. If you need more specialized projections, the FIRE Calculator models early-retirement timelines, and the Dividend Calculator focuses specifically on income-producing portfolios.

Investment Calculator Tips

1
Use a conservative return rate (6-7%) for long-term projections to avoid overestimating future wealth.
2
Increase your monthly contribution by even 1% each year; the cumulative effect over decades is substantial.
3
Compare monthly vs. annual compounding to see that frequency matters less than contribution consistency.
4
Run the calculator with zero initial investment to see how powerful regular contributions alone can be.
5
Model the impact of inflation by subtracting 2-3% from your expected return rate to see growth in today's dollars.

Frequently Asked Questions

1

What is compound interest?

Compound interest is interest earned on both your initial investment and previously earned interest. Over time, this 'interest on interest' creates exponential growth. The more frequently interest compounds, the faster your money grows.
2

What's a realistic annual return rate?

Historical stock market returns average about 7-10% annually after inflation. Bonds typically return 3-5%. A diversified portfolio might expect 6-8%. Higher returns usually come with higher risk.
3

How does compound frequency affect returns?

More frequent compounding results in slightly higher returns. Monthly compounding earns more than annual compounding at the same rate. However, the difference is usually small compared to the impact of time and contribution amounts.
4

Should I contribute at the beginning or end of the period?

Contributing at the beginning of each period gives your money more time to compound, resulting in slightly higher returns. However, for most people, the important thing is consistency rather than timing.
5

How do taxes affect investment growth?

This calculator shows pre-tax growth. Actual returns depend on account type (taxable vs. tax-advantaged like 401k/IRA) and your tax bracket. Tax-advantaged accounts let your money compound without annual tax drag.

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