Calculators that get the conventions right
Free to use with no account. Each one states on the page which lender convention it follows, so you can tell whether its answer is the one your credit committee would get. If there is a calculation you keep rebuilding in a spreadsheet, write to support@altyst.ai and it moves up the list.
NOI calculator
Gross rent, vacancy, other income and operating expenses in; effective gross income, total expenses, net operating income and the expense ratio out, with a statement you can send line by line.
Which expenses go above the line, the management fee base, reserves under both conventions, and why a broker NOI and a lender NOI disagree.
Open the calculatorLoan sizing calculator
Size a commercial mortgage against loan to value, minimum DSCR, and minimum debt yield at the same time, and find out which of the three is holding your proceeds down.
DSCR, debt yield, LTV, the mortgage constant, interest only, and the balloon at maturity.
Open the calculatorCap rate calculator
Enter any two of NOI, price, and cap rate and it solves the third, then re-solves the value at cap rates a quarter, half, and full point away so the reciprocal is visible in dollars.
Going-in versus stabilized versus exit, which NOI belongs in the numerator, and why a cap rate cannot size the debt.
Open the calculatorDSCR calculator
Enter any two of NOI, annual debt service, and DSCR and it solves the third, turns a loan quote into the payment, and shows how far NOI can fall before 1.00x and the common covenant levels.
The cushion in dollars, going-in versus stressed coverage, interest-only flattery, and why a DSCR alone cannot size the loan.
Open the calculatorCash-on-cash calculator
Price, loan, NOI, rate, and closing costs in; equity, year-one cash flow, and the cash-on-cash out, with the return re-solved 50 and 100 basis points in each direction.
The all-in denominator, what the metric ignores, negative leverage, and the rate table in dollars of cash flow.
Open the calculatorGross rent multiplier calculator
Enter any two of price, annual gross rent and the multiplier and it solves the third, then translates the multiplier into the going-in cap rate it implies at expense loads you can move.
Annual versus monthly multipliers, the exact bridge to a cap rate, and why the same multiplier spans three points of yield.
Open the calculatorBreak-even occupancy calculator
Operating expenses, reserves and debt service against gross potential income give the occupancy where the property stops covering its costs, with the cushion in points and in dollars of rent.
What a lender means by the default ratio, why reserves belong in it, the interest-only trap, and how it relates to DSCR.
Open the calculatorDebt yield calculator
Enter any two of NOI, loan and debt yield and it solves the third, shows what each conventional floor would advance, and ties the answer back to the cap rate and the leverage.
Why lenders added a third test, the exact identity linking debt yield to cap rate and LTV, and why a low cap rate caps the advance rate whatever the coverage says.
Open the calculatorCommercial mortgage calculator
Loan, rate, amortization, term and interest-only months in; the monthly payment, the annual debt service, the mortgage constant, the balance still owed at maturity and the schedule out.
Why amortization and term are different fields, what the balloon really is, what an interest-only period costs in interest and in balance, and the payment step when it ends.
Open the calculatorIRR calculator
Equity, NOI and its growth, the payment, the hold and the net sale proceeds in; the year-by-year cash flows, the internal rate of return, the equity multiple, the payback year and the present value out.
Why there is no formula for it, why levered cash flow grows faster than rent, where a published IRR is usually overstated, and when one series has more than one answer.
Open the calculatorMultifamily underwriting model
A working ten-year acquisition model in Excel. Rent roll, T-12 normalization, an eleven-year pro forma, debt sized on three tests, returns, and three two-way sensitivity grids. Yours to edit and pass on.
2,718 live formulas across eleven tabs, nineteen internal checks, no protected sheets and no macros.
Download the modelPut a tool on your own site
Every calculator here is embeddable. One iframe, no account, no key. The framed page loads no advertising script and sets no cookie on your readers. Keep the credit line and it is yours to use, including on a commercial site.
The code, the parameters, and exactly what the frame is allowed to do.
Get the embed codeWhy these are free and ungated
A calculator behind an email form is a lead capture with a calculator attached, and it offers a bad trade: your address in exchange for arithmetic you could do in a spreadsheet. Nothing here asks for an address, and no part of the answer is held back until you sign up.
They are also not toys. The loan sizing calculator is checked case by case against the same deterministic engine that runs inside the product, and the two agree to the cent. Anything published here has to clear that bar before it goes up. Where a convention is ambiguous the page names the one it follows, because a number without its convention is not an answer yet.
What they will not do is underwrite a deal. A calculator takes numbers you already know. The product reads the offering memorandum, the rent roll, and the T-12 to work out what those numbers are, then carries them through debt, leasing, exit, and the Excel workbook.
Past the calculator
Bring the documents and get the whole model instead of one ratio.