Compound Interest & Wealth Growth Calculator
Calculate how your initial investment and monthly contributions grow over time with compound interest.
Reviewed by: Marcus Vance, CFA • Quantitative Finance Review Board
Methodology: Verified Formula
Presets:
Future Portfolio Value
$206,088
Total Contributions
$100,000
Total Interest Earned
$106,088
Compound interest generates 51.5% of your final balance.
Scenario Comparison & Benchmark Table (Compound Interest)
Compare how scaling Initial Investment ($) affects your output (click any row to load those values into the calculator above):
| Initial Investment ($) | Future Portfolio Value | Total Contributions | Total Interest Earned |
|---|---|---|---|
| 5,000 | $189,554 | $95,000 | $94,554 |
| 7,500 | $197,821 | $97,500 | $100,321 |
| 10,000 (Baseline) | $206,088 | $100,000 | $106,088 |
| 12,500 | $214,356 | $102,500 | $111,856 |
| 15,000 | $222,623 | $105,000 | $117,623 |
| 20,000 | $239,158 | $110,000 | $129,158 |
Mathematical Formula & Step-by-Step Guide
Primary mathematical equation used by this model:
FV = P × (1 + r/12)^(12×t) + PMT × [((1 + r/12)^(12×t) - 1) / (r/12)]
- Configure your primary input (Initial Investment ($), baseline set to 10,000) using either the direct numeric box or synchronized range slider.
- Adjust the remaining parameters (Monthly Contribution ($), Annual Interest Rate (%), Investment Horizon (Years)) to mirror your exact scenario.
- Examine the primary output alongside the secondary breakdown metrics and the 6-tier benchmark comparison table below.
Primary Standards & References: Federal Reserve H.15 Selected Interest Rates, CFPB Regulation Z (Truth in Lending Appendix J), IRS Publication 590 & SEC Investor.gov Compounding Methodology
Financial models are for educational planning and scenario comparison only and do not constitute fiduciary investment, tax, or mortgage lending advice.
Financial models are for educational planning and scenario comparison only and do not constitute fiduciary investment, tax, or mortgage lending advice.
Frequently Asked Questions — Compound Interest
What mathematical formula does the Compound Interest & Wealth Growth Calculator use?
This calculator implements the verified relationship: FV = P × (1 + r/12)^(12×t) + PMT × [((1 + r/12)^(12×t) - 1) / (r/12)]. Each variable (Initial Investment ($), Monthly Contribution ($), Annual Interest Rate (%), Investment Horizon (Years)) is evaluated in real time using double-precision floating-point arithmetic so there is zero rounding drift across multi-step scenarios.
How does changing Initial Investment ($) impact the final result?
Initial Investment ($) acts as the primary driver in this model (default baseline: 10,000). Use the Reference Benchmark Table on this page to compare how scaling Initial Investment ($) from conservative to aggressive levels changes both the primary outcome and secondary ratios.
What standards and sources back this Compound Interest methodology?
Our model is audited by Marcus Vance, CFA • Quantitative Finance Review Board and calibrated against Federal Reserve H.15 Selected Interest Rates, CFPB Regulation Z (Truth in Lending Appendix J), IRS Publication 590 & SEC Investor.gov Compounding Methodology. Note: Financial models are for educational planning and scenario comparison only and do not constitute fiduciary investment, tax, or mortgage lending advice.