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Compound Interest Calculator

The Power of Quiet Compounding

Wealth isn’t built in a day; it’s built in the margins of decades. This engine separates your hard work from the market’s heavy lifting. Visualize the exact moment your portfolio momentum starts working harder than you do—a moment we call the “Momentum Flip.”

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Important Warning: If you are currently battling high-interest debt, compound interest is your enemy, not your friend. Do not begin an aggressive investment plan yet. Go to the Debt Snowball Calculator to clear the runway first.

Variables

Timeline

Age

Retire

Start

Current Balance

Income & Flow

Salary

Monthly Contrib.

Contrib. Increase

Increase Duration

Assumptions

Return

Inflation

Drawdown Strategy

Monthly Withdrawal

WEALTH LEAK

Don't Let Debt Kill Your Gains

Your 8% investment returns don't matter if you're paying 20% interest on credit cards. Plug the hole in your bucket first.

Launch Debt Destroyer →

EXPENSE OPTIMIZER

Slash Your Housing Cost

Every dollar saved on your mortgage is a dollar that can compound here. See if you can lower your monthly overhead.

Calculate Savings →

5 Years

10 Years

20 Years

Retire Age
$0

Growth trajectory

Financial Momentum

Critical tipping points where your money starts doing the heavy lifting.

The First $100k is the Hardest

Watch how the time between each $100k milestone shrinks as compound interest takes over.

Wealth Legacy

Legacy @ 90

Assets projected at age 90. Optimize your wealth transfer today.

Yearly Breakdown

Age	Start	Contribution	Withdrawal	Growth	End

How to Read Your Trajectory

The chart above isn’t just a projection; it’s a visualization of your future financial freedom. Here is how to interpret the data:

The Total Balance (The Top Curve): This represents the combined value of your wealth—every dollar you’ve contributed plus every dollar the market has earned for you.
The Interest Earned (The Shaded Area): This is your “Free Money.” Notice how this area expands vertically over time. This is the visual representation of compounding—your money doing the heavy lifting so you don’t have to.
The Principal (The Base Layer): This represents your “Sweat Equity”—the actual dollars you have deposited from your salary.

Finding Your “Freedom Dates” (The Milestone Tab)

While the chart shows the curve, the Milestones Tab provides your specific coordinates for freedom. Toggle to the Milestones view to find two critical dates:

The Momentum Flip (Interest > Contributions): Look for the age when your annual interest earnings exceed your annual contributions. This is the moment your portfolio becomes a self-sustaining engine.
The Independence Point (Interest > Salary): Look for the age when your annual interest matches your current take-home pay. This is the mathematical definition of financial independence—where your assets can officially “replace” your labor.

Two Ways to Win (Strategic Playbooks)

Strategy 1: Coast FIRE

The Move

Aggressively front-load investments in your 20s and 30s.

The Result

You reach a “Critical Mass” where you can stop contributing entirely. The existing pile is large enough to carry you to retirement.

Best For

High earners who want to “downshift” their career in their 40s.

Strategy 2: The Accelerator

The Move

Commit to saving 50% of every future raise. You won’t feel the pinch because your paycheck still grows, but your savings rate skyrockets.

The Result

This method fights “Lifestyle Creep” and can shave 10–15 years off your working life.

Best For

Employees expecting consistent salary growth.

The Cost of Waiting

Time is the heaviest variable in this equation. Delaying your investment journey by just 5 years doesn’t just push retirement back—it deletes the final (and largest) compounding cycles.

The Math: Investing $500/month at 8% starting at age 25 yields $1.7 million by age 65.
The Delay: Waiting until age 30 drops that total to $1.1 million.
The Reality: That 5-year hesitation cost you $600,000.

Note: These figures are for illustrative purposes. Your actual results will vary based on your specific contributions, market returns, and the timing of your investments.

Frequently Asked Questions

How does compound interest differ from simple interest?

Simple interest is calculated only on the principal amount (the original deposit). Compound interest is calculated on the principal plus the accumulated interest from previous periods. This creates an exponential growth curve over time. This tool visualizes that curve, differentiating between the "Total Contributions" (money you put in) and the "Hypothetical Growth" (interest earned on interest).

Is the "Hypothetical Growth" rate guaranteed?

No. The growth rate input into this calculator is a variable for estimation purposes only. Actual market returns fluctuate based on economic conditions, asset allocation, and inflation. This tool projects a constant rate of return to illustrate the mathematical power of time and consistency, but it does not predict future market performance or guarantee a specific profit.

Why does the frequency of contributions matter?

The frequency at which funds are added and compounded impacts the final total. This calculator assumes monthly contributions to reflect standard investing behavior (e.g., monthly 401k or IRA deposits). Contributing smaller amounts frequently often yields better long-term results than larger, infrequent lump sums due to the mechanics of compounding—the sooner the money is invested, the longer it has to generate returns on itself.