How MB CALC works
MB CALC turns a few facts about your property into a modeled journey — and shows you the assumptions it used along the way. You can change any of them and watch what happens.
The flow
- Enter your property facts. Value, mortgage balance, rate and term, taxes, insurance, HOA if any, current market rent, and your current reserve balance.
- See the Starting Assumptions. The defaults MB CALC would use for growth, vacancy, maintenance, management, inflation, and a modeled S&P return.
- Accept them, or change them. Nothing is hidden; changed values are flagged.
- See the journey. Owner Support, Reserve Requirement, the Projected Turning Point, and the Production Phase that follows.
- Ask “What has to happen?” See the rent, costs, and reserve position at the Turning Point, so you can judge whether the assumptions are plausible.
- Run a Reality Check. Test less-favorable assumptions — lower rent growth, higher vacancy, higher maintenance or insurance, lower appreciation or return.
- Open the audit trail. A year-by-year table behind the summary, so every number can be traced.
The words MB CALC uses
| Term | Working meaning |
|---|---|
| Owner Support | Outside capital required to cover modeled negative rental cash flow. |
| Reserve Requirement | The greater of six months of gross monthly rent, or six months × 1.33 × monthly PITI + HOA. |
| Turning Point | The first modeled point when rental cash flow is at least zero and required reserves are fully funded. |
| Production Phase | The period after the Turning Point when positive cash flow maintains reserves and creates excess investable production. |
| Payback Point | The point when cumulative positive property production equals prior rental operating Owner Support. |
| Future Dollars | Nominal dollars in the future model year. |
| Today’s Dollars | Future amounts adjusted back to present purchasing power using the selected inflation assumption. |
| Starting Assumptions | Editable MB CALC defaults used to begin a scenario; not predictions. |
What MB CALC will never do
- Label a property GOOD, BAD, BUY, SELL, KEEP, WINNER, or LOSER.
- Call an assumption an expected outcome or a guarantee.
- Let appreciation or equity stand in for cash flow.
- Show an impressive future number without the assumptions that produced it.
- Blend cash flow, principal reduction, and appreciation into one headline figure.
MB CALC does not predict the future. It measures the consequences of assumptions.