Everything here is free and nothing is gated. No email required to use the calculators, and nothing you type is sent anywhere. They exist because the arithmetic that decides whether a deal works is not the arithmetic a listing site shows you.
The calculators
The Deal Screener
For rentals. It runs two numbers side by side: the DSCR your lender computes, which is gross rent divided by PITIA and ignores every reserve, and the cash you actually keep after vacancy, maintenance, capital expenditure and management. It also gives you break-even rent, the highest price that still clears the return you set, and the three ordinary ways a working rental stops working. When the two headline numbers disagree, that gap is the deal.
The Flip Filter
For flips. The 70% rule treats financing as free and time as weightless, and neither is true. This one prices origination points, interest across your real timeline, carry, both closings and a contingency, then shows the net, the return on the cash you actually bring, the resale price where you break even, and the highest offer that still works. On a six-month project the money and the calendar can cost more than the rehab.
The reference
The Investor Glossary
Forty terms in plain English, grouped by what they decide: market signals and supply, rates, financing a rental, seller credits and buydowns, flip financing, and rental underwriting. Beginners rarely lose money picking the wrong house. They lose it misreading a term on a term sheet.
How to use them together
Start with the glossary if a term on the calculator is unfamiliar, because a number you cannot define is a number you cannot check. Then run the property through the Deal Screener or the Flip Filter depending on what you plan to do with it. Read the bottom figures rather than the top one: break-even and the highest workable offer tell you what to write on the contract, while the headline return only tells you how the deal looks today.
The explainers behind the numbers
Each of these covers one input the calculators ask for, and why the default is what it is.
How to find months of supply for your market, and what number means buyers have the edge.
How to tell if you are really in a buyer's market, using three numbers and a two-of-three rule.
How to calculate effective rent when comparable units are offering a month free.
Why taxes and insurance jump when you buy a rental, and the two calls that catch it before you tour.
A note on what these are not
They are screening tools, not underwriting. They price the assumptions you give them, so a calculator fed an optimistic rent returns an optimistic answer with the same confidence as an honest one. Verify taxes with the county rather than the listing, get a landlord insurance quote rather than the seller's homeowner premium, and confirm loan terms with your own lender before you rely on any of it.
Educational only. Not financial, legal, or tax advice. Loan terms, operating costs, taxes and rents vary by lender, property, and location. Verify every assumption with qualified professionals before investing.
