What is this? This calculator models a private lending strategy: your capital funds short-term real estate notes (5-year, fully amortized) that pay monthly principal and interest. Every payment is reinvested into new notes — the "snowball" — until your portfolio is large enough to pay you a steady monthly income and keep itself running by continuously redeploying the surplus into fresh notes.
How to use it as an investor:
How to use it as an investor:
- Set how much you're starting with, any monthly contribution, and the note terms you expect.
- Choose your investment horizon — how many years you're giving this strategy.
- Set the monthly income you eventually want to collect (set it to $0 to see pure growth with no withdrawals).
- The calculator finds the earliest year your income can start and be sustained every single month through the end of your horizon — verified month-by-month so the portfolio never runs dry.
Capital and notes
The engine of the strategy: how much you put in, what you add along the way, and the terms your notes earn.
Starting capital
Total amount you invest on day one. It is immediately deployed into as many notes as possible.
$30K$265K$500K
Monthly contribution
Extra cash you add every month during the snowball phase. Contributions stop the day your income starts.
$0$5K$10K
Note size
Face value of each individual note. Cash is redeployed into a new note as soon as this amount accumulates.
$30K$40K$50K
Interest rate
Annual rate each note pays. All notes are 5-year fully amortized — principal and interest come back monthly.
12%14%16%
Goal and timeline
Your personal plan: how long you'll run the strategy, the income you want, and where idle cash sits in between.
Investment horizon
Total years you'll run the strategy — snowball years plus income years combined.
5 yrs12 yrs20 yrs
Target monthly income
The amount you want to collect every month once the portfolio can sustain it. Set to $0 to see pure compounding with no withdrawals.
$0$10K$20K
Money market rate
Yield earned by cash sitting between note purchases — it's never idle.
0.5%2.75%5%
Your plan in one sentence
🎯 Total income goal
★ Sustainable crossover point
Portfolio value
Everything in dollars on one scale · blue = money working in notes · green = cash between deployments
S&P 500 off
Active notes
How many notes are working for you at any moment — on its own scale so it's easy to read
Monthly cash flow
Orange = income you keep · blue = reinvested into new notes · dashed = your target
Cumulative income collected
Year-by-year
Crossover verified by forward simulation: income only starts at the earliest month from which the target can be paid every single remaining month — cash never negative, notes never zero. Monthly contributions apply during the snowball phase only. All notes 5-year fully amortized. S&P 500 comparison at 11.2% CAGR (20-year historical average through 2026, dividends reinvested); S&P scenario includes the same monthly contributions for a fair comparison. This is an illustrative model, not investment advice. Past performance does not guarantee future results.