What the calculation measures
Cash invested should include the down payment plus other acquisition cash such as closing costs and initial rehab when those are part of the investment.
How to interpret the result
Use cash-on-cash return to understand leveraged cash yield, not property appreciation or total return.
Run scenarios instead of one answer
Change the most uncertain input and compare outcomes. A calculator is most useful when it shows sensitivity, not when one estimate is treated as a guarantee.
Limits and assumptions
Tax effects, principal paydown and future sale proceeds are outside this simple cash-yield metric.