Investment Calculator.

See how your investments grow over time with compound interest and regular contributions.

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1 yr 20 years 40 yrs

Displays future balance in today's purchasing power (assuming 3% average inflation).

Include 401(k) matching in your calculation.

How Compound Interest Works

Compound interest is interest earned on both your initial principal and previously earned interest. The formula is: A = P(1 + r/n)^(nt)

The key factors are: time (the longer, the better), rate of return (higher returns compound faster), and regular contributions (even small monthly additions make a big difference over decades).

For example, investing $10,000 with $500 monthly contributions at 8% annual return over 20 years grows to approximately $344,000 — that's $130,000 in contributions and $214,000 in interest earned.

By regularly contributing to an investment account, you ensure that both your principal and the interest earned grow exponentially.

Frequently Asked Questions

How does compound interest work?

Compound interest is interest calculated on your initial principal plus all of the accumulated interest from previous periods. Over time, compounding causes your investment balance to grow exponentially as you earn return on top of return.

What is the rule of 72?

The Rule of 72 is a quick mental formula used to estimate how long it will take for an investment to double in value at a fixed rate of return. Simply divide 72 by your annual interest rate (e.g., at a 6% return, it takes 12 years).

Why MyPaycheckCalculator is Better

If you are looking for a private, faster Investment Growth Calculator or search for a secure SmartAsset investment calculator alternative, we offer a modern, uncluttered alternative. Here is how our utility compares to legacy traditional options:

Recommended

MyPaycheckCalculator Advantage

  • Model savings growth and compound yields instantly on one page.
  • Completely private: your investment calculations run strictly local.
  • Clean UX with smooth, layout-stable compound interest visual outputs.

Legacy Calculator Drawbacks

  • Drives users toward high-commission financial advisory matchmaking programs.
  • Monitors personal savings and compound asset projections using marketing cookies.
  • Overloads investment calculations with slow advertising script widgets.