Tools / Napkin Math Calculator

Napkin Math Calculator

Quick pro forma underwriting for multifamily and small commercial assets. Drop in a handful of inputs and get a clean read on NOI, cap rate, and cash flow.

Snapshot

Monthly NOI N/A

Cap Rate N/A

Monthly Cash Flow N/A

Total Cash Required N/A

All figures are estimates based on inputs below.

Income

Rent and other income

Income cadence

Unit count

Rent per unit (monthly)

Other income (monthly)

Expenses

Operating expenses

Percent inputs use gross potential rent (GPR).

Expense mode

Vacancy

$ %

Management fee

$ %

Maintenance reserve

$ %

Capex reserve

$ %

Property taxes

$ %

Insurance

$ %

Owner-paid utilities

$ %

Other operating

$ %

Financing

Debt and acquisition

Purchase price

Down payment

$ %

Interest rate

Term

yrs

Closing costs

$ %

Improvement costs

$ %

How this works

The calculator applies vacancy to gross rent, then subtracts operating expenses to get NOI. Debt inputs estimate payment-driven cash flow and return metrics. This is a fast underwriting tool, not a replacement for a full pro forma.