← Back to BlogMay 20268 minDan White
Rental Cash Flow Calculator — Free Tool for Investors
Positive cash flow means the property pays you every month. Negative cash flow means you pay it. The only way to know which side you are on is to run the actual numbers — not gut feelings, not the seller's projections.
Market Context
Live Market Data
Washington, DC Housing Market
Cool Market
Data through Mar 2026
Median Sale Price
$590,000
+0.8% YoY
Median Days on Market
44 days
lower = faster market
Sale-to-List Ratio
99.7%
buyers' market
Homes Sold
4,457
last reported month
Source: Redfin Data Center. Updated monthly. Data reflects Washington, DC residential sales.
redfin.comCash Flow Formula
Monthly Cash Flow = (Gross Rent − Vacancy − Expenses) − Mortgage
Every Expense That Reduces Cash Flow
- Vacancy allowance: 5–8% of gross rent — budget it even in tight markets
- Property taxes: Use the actual annual bill divided by 12
- Insurance: Landlord policy, typically $80–$180/month
- Property management: 8–12% of collected rent if not self-managing
- Maintenance: 5–10% of gross rent annually for average-age property
- CapEx reserves: 5–8% of gross rent for major replacements
- HOA: If applicable — often overlooked
Calculate Your Rental Cash Flow Free
Freddie runs monthly and annual cash flow projections with every expense category included — free in one conversation.
Calculate My Cash Flow Free →Why the 50% Rule Isn't Enough
The 50% rule estimates half your gross rent covers operating expenses. It's useful for a 30-second screen. But a real cash flow analysis uses your actual tax bill, an insurance quote, your specific PM rate, and a realistic vacancy assumption for that market. The 50% rule will get you close — a real analysis tells you if you actually make money.
Dan White is a licensed Virginia real estate agent at Pearson Smith Realty and founder of FreeDealCalc.com. He has been investing in real estate for 20+ years.