Investment Property Mortgage Calculator
Calculate the full picture for a rental property — mortgage payment, monthly cash flow, cap rate, cash-on-cash return, and DSCR — to see if a deal works before you put in an offer.
| Loan Details | |
| Loan Amount | — |
| Cash Required (Down + Closing + Rehab) | — |
| Monthly P&I Payment | — |
| Income | |
| Gross Rent | — |
| Vacancy Loss | — |
| Effective Gross Income | — |
| Operating Expenses | |
| Taxes + Insurance + HOA | — |
| Management Fee | — |
| Maintenance | — |
| CapEx Reserve | — |
| Total Operating Expenses | — |
| Returns | |
| Net Operating Income (annual) | — |
| Annual Debt Service | — |
| Annual Cash Flow | — |
| DSCR (Debt Service Coverage) | — |
What an Investment Property Mortgage Calculator Does
An investment property mortgage calculator combines loan amortization with rental property cash-flow analysis to give you the four numbers that decide whether a deal works: monthly cash flow, cash-on-cash return, capitalization rate (cap rate), and debt service coverage ratio (DSCR). It accounts for vacancy, management, maintenance, capital expenditure reserves, and the higher down-payment and rate requirements of investment loans — line items that a basic mortgage calculator omits but that determine real-world profitability.
Conventional Fannie Mae and Freddie Mac investment property loans require a minimum 15% down for single-family rentals (20% to qualify for the best rates) and 25% down for 2-4 unit properties, per Fannie Mae's selling guide. Investment property rates run 0.5-1.0 percentage point higher than owner-occupied, and lenders use 75% of expected rental income to qualify you (the 25% haircut accounts for vacancy and management).
Cap Rate, Cash-on-Cash, and DSCR — What Each Tells You
Cap rate is net operating income (NOI) divided by purchase price. It measures the property's return ignoring financing — useful for comparing properties. A 6-10% cap rate is healthy in most US markets in 2026; below 5% means appreciation is doing the heavy lifting; above 10% often signals a high-risk neighborhood or property condition issues.
Cash-on-cash return is annual cash flow divided by total cash invested (down payment, closing, rehab). It includes financing — so leverage amplifies it. Target 8-12% cash-on-cash for a solid deal in most markets. DSCR is NOI divided by annual debt service. DSCR loans are non-QM products underwritten on the property's cash flow rather than your personal income — most DSCR lenders require a minimum DSCR of 1.20-1.25 to approve.
Investment Property vs Primary Residence Loans
Investment loans differ from primary residence loans in five major ways: higher down payment (15-25% vs 3-20%), higher interest rates (+0.5-1.0%), stricter DTI limits, no FHA or VA option, and inclusion of 75% of projected rental income for qualification (existing rentals require a 2-year history). Some investors use DSCR loans to escape DTI limits — these qualify on property cash flow alone but charge 1-2% higher rates than conventional.
The 1031 exchange (Section 1031 of the Internal Revenue Code) allows you to defer capital gains tax when selling one investment property and buying another of equal or greater value within 180 days. See our 1031 exchange calculator for the deferred tax math, and depreciation recapture calculator for the IRS clawback when you eventually sell.
Common Pitfalls in Rental Property Math
The most common mistake is forgetting the "non-PITI" expenses: vacancy (4-8% in most markets), management (8-10% if you hire out), maintenance (5-15% depending on age), and CapEx reserves for big-ticket replacements. Beginners often calculate cash flow as just "rent minus mortgage payment" and end up with negative cash flow once a tenant moves out or the water heater fails. Use this calculator's full expense model to avoid that trap.
Last updated May 2026. Sources: fanniemae.com, irs.gov, cfpb.gov.