MB CALC Starting Assumptions
MB CALC needs to make assumptions about the future to model your property. These are not predictions. They are simply the starting assumptions used for a calculation. Every one of them can be changed, and changing them changes the result.
| Assumption | Version 1 starting value | Editable |
|---|---|---|
| Rent growth | 5% annually | Yes |
| Property appreciation | 4% annually | Yes |
| Property tax growth | 2% annually | Yes |
| Insurance growth | 3% annually | Yes |
| HOA growth | 3% annually | Yes |
| Vacancy | 5% of gross scheduled rent | Yes |
| Rental maintenance | 10% of gross scheduled rent | Yes |
| Property management | 10% of gross scheduled rent | Yes |
| Owner-occupied maintenance allowance | 1% annually | Yes |
| S&P 500 modeled return | 9% annually | Yes |
| Inflation | 3% annually | Yes |
| Retirement portfolio withdrawal | 3% annually | Yes |
Under the starting vacancy, maintenance, and management values, those three together equal 25% of gross scheduled rent — often summarized as “Gross Rent × 75% − P&I − Taxes − Insurance − HOA.” The percentages stay adjustable; the model uses whatever you select.
Not predictions
MB CALC does not predict the future. It measures the consequences of assumptions.
A 9% modeled S&P return is a hypothetical input for education, not an expected or guaranteed return. Actual investment returns fluctuate and may be negative.