Investments
Compound Interest calculator
See how your money snowballs with consistent contributions.
Your inputs
$
$
%
Results
Future value
$548,915
Total contributions
$160,000
Interest earned
$388,915
Growth multiple
3.43x
Breakdown
Total: $548,915
Where your future value comes from
0%25%50%75%100%
- Initial deposit$10,0001.8%
- Your contributions$150,00027.3%
- Interest earned$388,91570.9%
Decision Engine
Should you go for this?
Compounding will meaningfully build wealth.
Strong Growth
Financial fit score100/100
Return rate
8.00%
≥ 7% ideal
Horizon
25 yrs
≥ 20 ideal
Final value
$548,915
Working in your favor
- 8.00% matches historical stock market returns.
- Long horizon lets compounding do the heavy lifting.
AI Insight
Personalized analysis from your numbers
Tap Generate for an AI-written breakdown of what your numbers mean, plus tailored next steps.
Share link
About this calculator
What the Compound Interest calculator does
The Compound Interest Calculator projects how an initial deposit plus consistent monthly contributions grow when returns are reinvested over time.
How to use it
- Enter your details: Initial deposit, Monthly contribution, Annual return, Years to grow.
- Results update instantly as you type — no submit button needed.
- Tap an info icon next to any field for guidance on what to enter.
- Use the Share button to save a permalink that restores your exact inputs.
- Tap Generate on the AI Insight card for a personalized written breakdown.
Tips & context
- Time matters more than amount — starting 10 years earlier often beats doubling contributions later.
- The S&P 500's long-run real return is roughly 7%; nominal averages 8–10%.
- Inflation erodes future value; subtract ~3% from your assumed return for a real-purchasing-power view.
Formula
FV = P(1+r)ⁿ + PMT · ((1+r)ⁿ − 1) / r, where r is the monthly return and n is months.
FAQ
Frequently asked
Is the return guaranteed?+
No — market returns vary year to year. Use this as a planning projection, not a promise.
Are taxes modeled?+
No. Tax-advantaged accounts (401k, IRA, Roth) shelter most of this growth.