Rental Cash Flow Calculator
Enter the monthly rent, a vacancy allowance, the monthly operating expenses and the mortgage payment. You get the effective rent, the monthly net operating income, the cash flow per month and per year, and the expense ratio. Nothing is sent anywhere.
In one sentence: Cash flow is what is left of the rent each month after vacancy, running costs and the mortgage.
Formula: effective rent = rent × (1 − vacancy %); NOI = effective rent − operating expenses; cash flow = NOI − mortgage payment; annual cash flow = × 12; expense ratio = expenses ÷ effective rent × 100.
The four deductions
Rent minus mortgage is the calculation most first-time landlords do, and it is why so many are surprised by the first year. Four things come off the rent before anything is yours. Vacancy: the unit will be empty sometimes, so a share of rent is never collected. Operating expenses: property tax, insurance, repairs and maintenance, management, any utilities or service charges you pay, and a reserve for the big items. The mortgage: principal and interest. And, outside this calculator, income tax on the profit. The result after the first three is cash flow, and it is often a small fraction of the rent.
Estimating expenses
Actual bills beat rules of thumb, but for a property you do not own yet, work from the known items (tax, insurance, management fee) and add a maintenance reserve. The expense ratio line, expenses as a share of effective rent, is a check against similar properties: a very low ratio usually means something is missing rather than that the building is cheap to run. The mortgage payment comes from the business loan calculator or your lender's quote.
From cash flow to returns
Monthly cash flow times twelve is the annual cash flow that the cash on cash return calculator divides by your cash invested, and the annual NOI line is what the cap rate calculator divides by the price. A property with negative cash flow may still be worth owning for appreciation or equity build-up, but that is a decision to make knowingly, with the monthly shortfall in front of you.
Frequently asked questions
Should I include a management fee if I manage it myself?
Yes, at the rate a manager would charge. It shows the true return and makes the day you hand it over painless.
Where do capital improvements go?
Not in monthly expenses. Treat a new kitchen or roof as investment, and keep a monthly reserve in expenses for the wear that leads to it.
Is my data stored?
No. Everything runs in your browser.