Rental Cash Flow Calculator for Landlords

Aptoria

Features

Product

Resources

Company

Tools

Pricing

See the demo

Free calculator

Rental cash flow calculator

See what a rental clears each month and year after the mortgage, operating costs, and set-asides for vacancy and repairs. The estimate is based on the numbers you enter.

Get early access

Watch it work

The short answer

Last updated: July 2026

Rental cash flow is what’s left after every cost: rent minus the mortgage, operating expenses (taxes, insurance, utilities, management), and set-asides for vacancy and maintenance. A positive number means the property pays you; a negative one means it costs you each month. This estimate uses the numbers you enter and excludes taxes and appreciation.

Cash-flow calculator

What a rental clears each month.

Start from the rent, subtract the mortgage, operating costs, and set-asides for vacancy and repairs — and see the monthly and yearly cash flow.

Monthly rent

Monthly mortgage payment

Monthly operating expenses

Taxes, insurance, utilities, management, HOA — anything but the mortgage and the reserves below.

Vacancy allowance

20%

Maintenance / capex reserve

25%

Input-driven result

Your inputs

Formula

Result below

Monthly cash flow

$412

Rent $2,600 − mortgage $1,400 − opex $450 − vacancy $130 − reserve $208.

Annual cash flow

$4,944

Monthly cash flow × 12.

Monthly cash-flow composition

Rent

$2,600

Mortgage

-$1,400

Operating costs

-$450

Vacancy allowance

-$130

Reserve

-$208

Cash flow

$412

Estimate based on your inputs. Not a promise of results.

Estimate only. Vacancy and reserve are set-asides you budget as a share of rent, not bills you pay every month — actual costs vary. Excludes income taxes, appreciation, and loan principal paydown.

Get early access

Watch it work

How it works

How this tool works.

Cash flow is the number that tells you whether a rental pays you or you pay it. The rent is only the starting point — the mortgage, the operating costs, and the money you should set aside for empty months and repairs all come out before anything lands in your pocket.

This calculator subtracts all of it: enter the rent, the mortgage, monthly operating expenses, and a percentage for vacancy and for a maintenance reserve, and it estimates your monthly and annual cash flow. It’s an illustration from your inputs — a negative result shows in red so a money-losing deal is obvious.

Enter the monthly rent, the monthly mortgage payment, and your monthly operating expenses (taxes, insurance, utilities, management, HOA).

Set a vacancy allowance and a maintenance/capex reserve as a percentage of rent — the honest set-asides most owners forget.

The tool computes rent − mortgage − operating expenses − rent×vacancy% − rent×reserve% for the monthly figure, then multiplies by 12 for the year.

Every output is an estimate from your inputs; a negative number means the property costs you money each month at those figures.

Make the result useful

Stress-test the monthly surplus

Monthly cash flow is most useful when every recurring owner cost is included: debt service, taxes, insurance, HOA, management, utilities, and a realistic maintenance allowance. A result that omits known costs is not conservative just because it is positive.

Then test a lower-rent or higher-expense month. The point is not to predict the future precisely; it is to learn how much room exists before a normal disruption turns the result negative.

Worked example

If rent is $2,400 and modeled costs total $2,050, baseline cash flow is $350/month. A $150 increase in owner-paid utilities reduces that cushion to $200; a $300 repair month eliminates it.

Rental property bookkeeping →

Reconcile a rental bank account →

Answers

Questions, answered plainly.

Why subtract vacancy and a reserve if I’m not paying them right now?

Because they’re real, they just don’t arrive as a monthly bill. Units sit empty between tenants, and roofs and water heaters eventually fail. Budgeting a percentage of rent for both keeps a good-looking month from hiding a cost that lands all at once later.

What counts as operating expenses here?

Everything to run the property except the mortgage and the vacancy/reserve set-asides above — property taxes, insurance, utilities you cover, management fees, and HOA dues. Keep the mortgage out of this field; it has its own input.

What does a negative cash flow mean?

It means that, at the numbers you entered, the rental doesn’t cover its own costs each month — you’d be feeding it. That isn’t automatically a bad investment (appreciation and loan paydown still build equity), but you should go in knowing it.

Does this include taxes or appreciation?

No. It stops at pre-tax operating cash flow. It doesn’t model income taxes on your profit, the equity you build as the loan is paid down, or any appreciation — treat it as the monthly cash picture, not your total return.

Keep exploring

More tools for plan cash & accounting.

DSCR calculator

Estimate the debt-service coverage ratio — income ÷ loan payments.

Open tool →

Price per square foot calculator

Estimate price per square foot and rent per square foot.

Open tool →

Straight-line depreciation calculator

Estimate annual straight-line depreciation on a rental building.

Open tool →

Built by a landlord who's done every one of these jobs by hand.

Aptoria was built by an owner-operator managing a Brooklyn portfolio — the 11pm calls, the awkward rent texts, the April receipt-pile — not by a software team guessing at the problem.

Stop sizing the problem. Let the agent run it.

Free for your first unit. The calculator gives you the number; Aptoria does the work — and you approve what matters.

Start free

Automate rent collection

Aptoria

The modern operating system for rental portfolios. Built for landlords, by people who manage units.

Product