The numbers · Portfolio velocity simulator · Cashflow
How fast can the snowball actually roll?
Not a formula — a simulation. Savings and cashflow pool into the next down payment, seasoned doors refinance under the site's rule, and the clock tells you which year each door lands.
Inputs
Starting cash$60,000
Savings per month$1,500
Door price (today)$250,000
Down payment25%
Mortgage rate6.50%
Monthly rent (% of price)0.80% · $2,000
Operating costs (% of rent)40%
Appreciation3.5%/yr
Target monthly income$8,000
A real month-by-month simulation, not a formula: cashflow and savings pool into the next down payment (25% + 3% closing), values appreciate monthly, and recycling refis any 18-month-seasoned door back to 75% LTV — but only when the door still cashflows at 80% occupancy after the new loan.
Net worth and monthly income, twenty years
Equity + cashIncome /mo
Two different curves on one chart: equity is the wealth line, income is the freedom line. They cross their milestones years apart — that gap is the whole discipline of holding.
Target income year
> 20 yrs
When the portfolio first pays $8,000/month
Doors by year 20
6
Door #10 doesn't land in twenty years
Refis fired
0
Each one rule-safe: post-refi DSCR positive at 80% occupancy
The verdict
On these assumptions, $8,000/month doesn't arrive inside twenty years — the portfolio tops out around $3,925/month from 6 doors. The levers that actually move this: buy at a better rent yield, or push savings while the snowball is small. Appreciation barely moves the income line — it moves the equity line.
Door #2yr 5
Door #5yr 16
Income at yr 20$3,925/mo
Net worth at yr 20$1.68M