Compound Interest Calculator

Discover how time and consistent contributions transform modest savings into extraordinary wealth through the mathematics of compounding.

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Compound Interest Calculator

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Projected Portfolio Value

Total Value

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Principal
Contributions
Interest Earned

Compound Interest Formula

A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) / (r/n)]

Where P is principal, r is annual rate, n is compounding frequency, t is time in years, and PMT is your regular contribution amount.

WealthMetron Insight

What is Compound Interest?

Compound interest is the process by which interest is calculated not only on your initial principal, but also on all previously accumulated interest. This creates an exponential growth curve that becomes increasingly powerful over time — what Einstein allegedly called "the eighth wonder of the world."

The critical difference between simple and compound interest is that compounding allows your earnings to generate their own earnings. A dollar earned in interest this year becomes principal that earns interest next year.

How to Read Your Results

Your projected value is split into three components: your original principal, your total contributions over time, and the interest those dollars generated. For most long-term investors, interest will eventually dwarf both — which is the entire point of starting early.

Each bar shows that component as a proportion of your final total. Watch what happens to the interest bar when you increase the time period — that is compound growth made visible.

WealthMetron Insight

The most important variable in compounding is not your return rate — it is time. A decade's head start is worth more than an extra percentage point of return over a lifetime.