Understanding your rental property’s financial performance is one of the most important steps in real estate investing. Whether you’re a first-time investor, a landlord looking to analyze a new deal, or someone exploring passive income opportunities, a rental calculator can help you make smarter, more confident decisions.

Our BiggerPockets Rental Calculator-style tool is designed to quickly calculate your monthly cash flow, annual cash flow, and cash-on-cash return based on a few simple numbers. Instead of doing manual math or relying on guesswork, this tool gives you clear and accurate investment metrics in seconds.

In this guide, you’ll learn what the calculator does, how to use it, why its metrics matter, and how real estate investors use these numbers to evaluate rental deals. You’ll also find examples and answers to frequently asked questions.

What Is a Rental Calculator?

A rental calculator is a tool that helps you analyze the financial performance of a rental property. It uses your rental income, monthly expenses, and purchase price to determine whether the property will generate profit or result in negative cash flow.

The calculator on this page estimates:

• Monthly Cash Flow
• Annual Cash Flow
• Cash-on-Cash Return (%)

These three numbers are used widely in real estate investing—especially among BiggerPockets investors—to evaluate whether a deal is worth pursuing.

Key Metrics the Calculator Provides

1. Monthly Cash Flow

Monthly cash flow represents how much profit you make each month after expenses.
Formula:
Monthly Cash Flow = Rent – Expenses

If the number is positive, the property is profitable. If it’s negative, it costs you money each month.

2. Annual Cash Flow

This is simply your monthly cash flow multiplied by 12.
Formula:
Annual Cash Flow = Monthly Cash Flow × 12

Annual cash flow helps investors estimate how much profit a property will generate over a year, which is vital for long-term planning.

3. Cash-on-Cash Return (%)

Cash-on-cash return compares the annual cash flow to the purchase price of the property.
Formula:
Cash-on-Cash Return = (Annual Cash Flow ÷ Purchase Price) × 100

A higher percentage means a more profitable investment relative to the cost.

How to Use This BiggerPockets Rental Calculator Tool

Using the tool is extremely simple. Just enter three numbers:

Step 1: Enter Monthly Rent

This is the total amount you expect to collect from tenants each month.

Step 2: Enter Monthly Expenses

Expenses may include:

• Property taxes
• Insurance
• Maintenance
• Utilities
• HOA fees
• Repairs
• Property management
• Vacancy allowance
• And more

This field represents your total monthly cost to operate the property.

Step 3: Enter Purchase Price

This is the price you paid or expect to pay for the rental property.

Step 4: Click “Calculate”

The calculator instantly displays:

• Monthly cash flow
• Annual cash flow
• Cash-on-cash return

Step 5: Use the Reset Button

If you want to run a new analysis, simply click “Reset.”

Why These Calculations Matter for Investors

Every successful investor knows that buying real estate without analyzing the numbers is a mistake. Here’s why each metric matters:

✔ Cash Flow Helps You Stay Profitable

Positive cash flow ensures you’re not losing money every month.

✔ Cash-on-Cash Return Measures Your Investment Efficiency

It tells you whether the property is worth the initial investment.

✔ Quick Decision-Making

The calculator allows you to run the numbers on multiple properties quickly and compare deals instantly.

✔ Reduces Risk

You avoid overpaying or underestimating expenses.

✔ Helps Build a Strong Real Estate Portfolio

Investors often use these metrics to grow long-term wealth.

Example Calculation

Let’s walk through an example so you can see how the calculator works.

Example Input:

• Monthly Rent: $1,800
• Monthly Expenses: $900
• Purchase Price: $150,000

Step-by-Step Result:

• Monthly Cash Flow:
  $1,800 – $900 = $900
• Annual Cash Flow:
  $900 × 12 = $10,800
• Cash-on-Cash Return:
  ($10,800 ÷ $150,000) × 100 = 7.2%

What This Means:

A 7.2% cash-on-cash return is considered reasonable in many markets, and the property provides strong monthly cash flow. An investor might consider this a solid rental opportunity.

Tips for Using the Calculator More Effectively

1. Be Realistic With Expenses

Underestimating expenses is the most common mistake new investors make. Always include maintenance, repairs, and vacancy.

2. Compare Multiple Properties

Use the calculator for any rental property you’re considering so you can choose the best one.

3. Aim for Positive Cash Flow

Unless you're pursuing appreciation, negative cash flow is usually risky.

4. Factor in Long-Term Changes

Rents can rise, but so can taxes, insurance, and maintenance costs.

5. Use the Tool Before Making an Offer

Running the numbers early helps you negotiate better and avoid bad deals.

20 Frequently Asked Questions (FAQs)

1. What does a rental calculator do?

It calculates your monthly cash flow, annual cash flow, and cash-on-cash return to show how profitable a property is.

2. Is cash flow the most important metric?

Many investors consider it the most important because it shows monthly profit, but other factors like appreciation also matter.

3. What expenses should I include?

Include taxes, insurance, maintenance, vacancy, repairs, utilities, HOA fees, and property management—anything that costs money.

4. What is a good cash-on-cash return?

Many investors target 8–12%, but it varies by market and investment strategy.

5. Can a negative cash flow property still be a good investment?

Sometimes, if long-term appreciation is strong—but it’s risky.

6. Does this calculator include mortgage payments?

No, this version calculates based on rent, expenses, and purchase price only. You can add mortgage payments under expenses if needed.

7. Should vacancy be included as an expense?

Yes. Most investors allocate 5–10% of rent for vacancy.

8. Can I use this calculator for Airbnb properties?

Yes, but make sure to calculate accurate monthly averages for rent and expenses.

9. How accurate are the results?

They’re as accurate as the numbers you enter—more precise inputs mean better results.

10. Why is cash-on-cash return important?

It measures how efficiently your money is earning a return.

11. What is annual cash flow?

It’s your monthly profit multiplied by 12.

12. Is rent the same as gross income?

Yes—monthly rent is the total amount you collect before expenses.

13. Can I use this tool for commercial rentals?

Yes, as long as you input accurate numbers.

14. What purchase price should I enter?

Use the price you paid or expect to pay for the property.

15. What if the expenses are higher than the rent?

Your cash flow will be negative, meaning the property loses money monthly.

16. What is a cash-flowing property?

It’s a property that earns positive monthly profit after expenses.

17. Can I use estimates instead of exact numbers?

Yes—estimates work fine for initial deal analysis.

18. How often should I analyze rental properties?

Any time you consider a new investment.

19. Can I use this calculator on my phone?

Yes—the tool is mobile-friendly and works on all devices.

20. Is this similar to the BiggerPockets calculator?

Yes, it follows the same concepts and analysis method used by BiggerPockets investors.

Final Thoughts

A rental property can be one of the best wealth-building investments—if you analyze the numbers correctly. Our BiggerPockets-style rental calculator gives you quick, accurate financial insights so you can make confident investment decisions.

Whether you're evaluating your first rental property or comparing multiple deals, this tool helps you understand the financial potential of any rental investment in seconds. Use it often, experiment with different scenarios, and make smarter decisions backed by real data.