Real Estate Deal Analyzer Calculator: How to Underwrite a Rental Property

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A real estate deal analyzer is the spreadsheet that answers one question: should I buy this property? Not "does it feel like a good deal" or "what does my gut say" — but what do the numbers actually show when you run every metric a lender would check?

Most investors start with a back-of-napkin calculation: rent minus mortgage equals cash flow. That works for a rough filter, but it misses vacancy, maintenance reserves, insurance, property taxes, and the debt metrics lenders actually care about. A deal analyzer catches what napkin math misses.

The 6 Metrics Your Deal Analyzer Should Calculate

1. Net Operating Income (NOI)

NOI = Gross Rental Income - Vacancy - Operating Expenses

This is the starting point for everything. Operating expenses include property taxes, insurance, maintenance, management fees, and repairs. Mortgage payments are NOT included — NOI is a pre-financing metric.

2. Cap Rate (Capitalization Rate)

Cap Rate = NOI / Purchase Price

What the property yields before financing. Typical residential range is 5-8%. Below 4% in most markets means you are overpaying relative to the income the property generates.

3. DSCR (Debt Service Coverage Ratio)

DSCR = NOI / Annual Debt Service

Can the property's income cover the mortgage? Lenders want 1.20x or higher. Below 1.10x is a red flag — the property cannot comfortably service its debt. Most DSCR loans require 1.25x minimum.

4. Cash-on-Cash Return

Cash-on-Cash = Annual Pre-Tax Cash Flow / Total Cash Invested

Your actual return on the money you put in (down payment, closing costs, any rehab). This is the metric that tells you whether your capital is working hard enough. 8%+ is strong. Below 5% and you might as well buy an index fund.

5. Debt Yield

Debt Yield = NOI / Loan Amount

The metric commercial lenders use when DSCR looks marginal. It strips out the interest rate and amortization schedule to show pure property-level return on debt. 8%+ is safe. Below 7% and most lenders walk away.

6. IRR (Internal Rate of Return)

IRR = Time-weighted total return including cash flow + appreciation + principal paydown

The full picture over your hold period. Accounts for when cash flows arrive, not just how much. 12-15% is a good target for buy-and-hold residential. Calculating IRR by hand is painful — this is where a spreadsheet pays for itself.

What Free Calculators Miss

Free real estate calculators from BiggerPockets, Zillow, and YouTube channels typically cover NOI and Cap Rate. Some include Cash-on-Cash. Almost none include Debt Yield, IRR, or sensitivity analysis. Here is what you do not get:

When to use a free calculator: If your total investment is under $50K and it is your first or second deal, the BiggerPockets calculator is fine. Above that threshold, the math matters enough that institutional-grade metrics (DSCR, Debt Yield, sensitivity) will save you from a bad deal — or give you confidence to move on a good one.

How to Use a Deal Analyzer in 10 Minutes

A well-built deal analyzer spreadsheet should require fewer than 15 inputs. Here is the typical workflow:

  1. Property basics — Purchase price, address, property type, unit count
  2. Income — Monthly rent per unit, other income (laundry, parking, storage)
  3. Expenses — Property tax, insurance, maintenance estimate, management fee, vacancy assumption
  4. Financing — Loan amount, interest rate, amortization period, closing costs
  5. Read the verdict — NOI, DSCR, Cash-on-Cash, IRR, and GO/NO-GO appear automatically

Total time: 10 minutes if you have the listing details and a rough expense estimate. The spreadsheet does the rest.

All 6 metrics. One spreadsheet. 10 minutes.

The Deal Analyzer calculates NOI, Cap Rate, DSCR, Cash-on-Cash, Debt Yield, IRR, and gives you a GO/NO-GO verdict. Includes Lender Solver and sensitivity analysis. Lite $9 / Pro $29.

Get Lite — $9 See Pro — $29

Frequently Asked Questions

What is a good cap rate for a rental property in 2026?

In most markets, a 5–8% cap rate is considered healthy for residential rentals. Class A suburban markets often trade at 4–5% because buyers accept lower yield for lower risk. Value-add and secondary-market properties typically price at 7–9%. Below 4% in most markets means you are overpaying relative to cash flow — appreciation is doing most of the work.

What DSCR do lenders require for an investment property?

Most conventional and DSCR lenders require a minimum 1.20 DSCR — meaning the property generates 20% more income than it costs to service the debt each year. Some lenders accept 1.10 on strong-market properties. Below 1.0 means the property does not cover its own debt and virtually no institutional lender will fund it without additional collateral.

What is the difference between cash-on-cash return and IRR for real estate?

Cash-on-cash return measures annual pre-tax cash flow divided by total cash invested — it shows your current yield on the money you put in. IRR (internal rate of return) measures the time-weighted total return over your entire hold period, including appreciation, principal paydown, and all cash flows. Cash-on-cash tells you how the deal performs today. IRR tells you the full picture if you hold for 5–10 years and exit.

How do I calculate NOI for a rental property?

NOI (Net Operating Income) equals Gross Rental Income minus Vacancy minus Operating Expenses. Operating expenses include property tax, insurance, maintenance, management fees, and capital reserves — but exclude debt service and depreciation. NOI is the pre-financing income figure that buyers and lenders use to value the property and size the loan.

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