Future Net Worth Simulator — Spend vs Invest
Compare two real compound-interest projections: keep spending vs start investing · free, no signup
See Future Net Worth Simulator — Spend vs Invest in action
Future Net Worth Simulator
Enter your current savings, a number of years to project, a monthly amount you currently spend, the amount you'd invest instead, and an assumed annual return rate. This tool runs the standard future-value-of-an-annuity compound interest formula, compounded monthly, to show two real side-by-side paths: your money left as-is versus invested.
The assumed return rate is clearly labeled and adjustable — this is an illustrative projection based on a stated assumption, not a guarantee, and is not investment advice.
Key features
Real compound-interest formula
Standard future-value-of-an-annuity math, compounded monthly.
Two paths side by side
Spend vs invest, both shown with their totals.
Adjustable assumed return
Change the rate to model different scenarios.
Fully transparent
The formula and assumption are stated plainly.
How to use it
- Enter your current savings.
- Enter years to project.
- Enter the monthly amount you'd invest instead of spending.
- Set an assumed annual return rate and see both paths.
Worked example
Example
$2,000 saved, $400/month invested at 7%/year for 20 years grows to roughly $210,000, versus the $2,000 alone if never invested.
Who uses this tool
Anyone deciding whether to start investing
See the real math behind consistent investing.
Students learning compound interest
A hands-on formula demonstration.
Financial content creators
A transparent, shareable projection tool.
Tips for the best results
- Use a conservative, realistic return assumption rather than an optimistic one.
- Re-run the simulation with a few different rates to see a range of outcomes.
- Remember this is a projection, not a guarantee — real markets fluctuate.
Common mistakes to avoid
- Assuming the projected number is guaranteed — it depends entirely on the assumed return actually happening.
- Forgetting to account for inflation, which this simple model does not separately subtract.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
Is the projected return guaranteed?
No, it's based on the annual return rate you assume; real investment returns vary and are not guaranteed.
What formula does this use?
The standard future value of a monthly annuity plus compounded principal, compounded monthly at your assumed annual rate.
Does this account for inflation?
No, it's a nominal projection; consider using a lower 'real' return rate to roughly account for inflation.
Is this investment advice?
No, it's an illustrative calculator, not personalized investment, tax or financial advice.
Can I model $0 monthly investment?
Yes, that shows how your current savings alone would grow with no further contribution.
Is my data stored?
No, everything is calculated locally in your browser.