Try it live — no signup
+$363
It Flows!Cap Rate
7.9%
DSCR
1.36
Cash-on-Cash
7.5%
1% Rule
1.05%
P&I at 7.08% (PMMS 6.48% + 0.6%). Syncing…
6.48%Freddie Mac Primary Mortgage Market SurveyUpdated today
AI Deal Interpretation
InvestIn the app, Invest turns each saved analysis into a plain-English summary — verdict, strengths, risks, and what to watch — using the same metrics you already entered. The figures above update only from your sliders here; AI interpretation runs on your full analysis after you sign in.
Rental Property Calculator for Cash Flow, DSCR & Cap Rate
Know if your rental property deal works before you offer.
Run the numbers on any rental property in seconds. Calculate monthly cash flow, cap rate, DSCR, cash-on-cash return, mortgage payment, and long-term return without building a spreadsheet.
Run your first deal · Free account, full calculator in the browser.
Built by a real estate investor, for real estate investors.
Features
Built like an investment property calculator — with investor judgment
Underwrite in minutes, not spreadsheet weekends. Browse housing market data, use free single-metric calculators, or open the full rental property calculator hub for how Will It Flow stacks the workflow.
Live KPI Dashboard
Slide price, rent, and rate — cash flow and return tiles respond instantly. Smart defaults keep you moving instead of hunting assumptions.
AI Deal InterpretationInvest
Plain-English strengths, risks, and what to watch — grounded in your dashboard metrics (never a black-box recalculation).
Quick Adjust Sliders
Stress down payment, rate, and price in seconds — watch cash flow and lender screens move with you.
Rent Comps & HUD Fair Market Rents
Zip-level HUD FMR benchmarks and trends on Inputs — one tap to drop a realistic rent into the model.
Multi-Year Projections
Hold-period cash flow, equity, and total return in charts — plan exit timing without rebuilding models.
BRRRR Analysis
ARV, refi proceeds, capital back in your pocket, and post-refi cash flow — see if the recycle math actually works.
Market Intelligence
Zip-level context (laws, timelines, demographics, opportunity signals). Invest unlocks deeper rent and pricing context on Outlook.
Stress Test Scenarios
Higher rates, vacancy, and expense spikes in one tap — know where the deal breaks before you wire earnest money.
Multi-Tenant Support
Duplex and small multi per-unit economics — GRM, price per unit, and break-even occupancy that match how you underwrite.
PDF Deal Sheets
One-page export with inputs and metrics — send it to a partner, lender, or mentor without formatting a deck.
Live Mortgage Rates
Current fixed rates and recent trend on your home screen — fewer tab hops when you are pricing debt.
Cloud Save & Favorites
Star the winners, attach a photo, reload from anywhere — your underwriting library stays with you.
Personal Defaults
Set vacancy, management, loan term, and growth once — every new deal starts with your assumptions, not generic ones.
Free calculators
Sharpen one metric — then load the full deal
Use focused tools for lender and yield screens, then open the rental property calculator in Will It Flow for saved analyses, PDFs, and market context. Browse housing market data when you need comps and trends.
Lender screen
DSCR Calculator
Check debt service coverage ratio and see whether a rental deal meets common lender thresholds.
Open calculatorYield benchmark
Cap Rate Calculator
Compare unleveraged yield from net operating income and property value before financing muddies the picture.
Open calculatorCapital recycling
BRRRR Calculator
Model purchase, rehab, refinance proceeds, cash left in the deal, and post-refi cash flow.
Open calculatorPayment math
Mortgage Payment Calculator
Estimate principal, interest, taxes, insurance, HOA, and monthly payment using current rate assumptions.
Open calculatorFast deal filter
1% Rule Calculator
Quickly screen rent-to-price ratio before spending time on a full rental property analysis.
Open calculatorHow It Works
From "maybe" to numbers — fast
New to underwriting? Use our rental property analysis checklist — then plug the line items straight into Will It Flow.
Create your free account
Email signup — your analyses, defaults, and favorites stay synced.
Enter a deal
Price, rent, and a few expenses. Smart defaults fill the gaps.
See cash flow instantly
Cash flow, cap rate, DSCR, and cash-on-cash update as you adjust sliders.
Save, export, repeat
Cloud saves, PDF deal sheets, and AI Deal Interpretation on Invest when you want a second brain.
Key Metrics
Cash flow first — then cap rate, DSCR, and hold math
Standard definitions, tied to your inputs. Walk the line items with our rental property analysis checklist. Isolate cap rate or DSCR assumptions with the free tools below.
Monthly Cash Flow
Income - Expenses - Mortgage$487
Positive
What hits your account after vacancy, OpEx, and debt service. The headline number before you chase IRR.
Cash-on-Cash Return
Annual Cash Flow / Total Cash Invested12.3%
Excellent
Return on the cash you actually wired — down payment, closing, rehab. The yield on real dollars out the door.
Cap Rate
NOI / Total Acquisition Cost7.2%
Strong
Unlevered yield so you can compare deals on price and income, independent of your loan structure.
DSCR
Net Operating Income / Annual Debt Service1.34
Solid
Stabilized NOI versus annual debt service — the coverage story DSCR lenders underwrite to.
IRR
IRR / Total Return Analysis14.2%
Strong
Annualized return across every inflow, outflow, and exit equity — the pro cross-deal comparison metric inside the app.
1% Rule Quick Screen
Monthly Rent / Purchase Price0.91%
Close
Fast filter before you spend hours on diligence — pair with the 1% rule calculator when you want the napkin math isolated.
Full stack in the app
BRRRR, small multi, depreciation, equity buildup, and hold-period charts — one login, no rebuild.
Core Analysis
- Monthly Cash Flow
- Cap Rate
- Cash-on-Cash Return
- DSCR
- NOI
- EGI
- Vacancy Loss
- PMI (with auto-drop)
- Break-Even Rent
- 1% Rule
Returns & Hold Period
- IRR
- CAGR
- Total ROI
- Equity Buildup
- Cumulative Cash Flow
- Depreciation (27.5yr straight-line)
BRRRR Analysis
- After-Repair Value
- Refinance Loan (75% LTV)
- Capital Returned
- Cash Left in Deal
- Post-Refi Cash Flow
- Post-Refi Cash-on-Cash
Multi-Family
- Gross Rent Multiplier (GRM)
- Operating Expense Ratio (OER)
- Price Per Unit
- Rent Per Unit
- Break-Even Occupancy
Stress Test Scenarios — Rates, vacancy, and expense shocks in one tap.
Market Intelligence — Zip-level rent, pricing, laws, and opportunity signals on Invest.
Frequently Asked Questions
Quick answers about Will It Flow. For deep dives, use the calculator directory or full FAQ page.
Is Will It Flow free to use?
Yes. Sign up and use the web app free. When native iOS and Android ship, those apps will be free to download too.
What is DSCR and why does it matter for rental property?
DSCR (Debt Service Coverage Ratio) is NOI divided by annual debt service — lenders use it to see whether rent clears the loan with cushion (often 1.25+). Will It Flow computes it from your inputs automatically. For threshold what-ifs, use the free DSCR calculator.
Does Will It Flow work for multi-family properties?
Yes — duplexes through small multis get per-unit economics: GRM, price per unit, break-even occupancy, and rent per unit alongside portfolio-level cash flow.
How is Will It Flow different from a spreadsheet?
Inputs drive every KPI in real time — no broken formulas or version files. You also get live mortgage rates, optional BRRRR and stress paths, cloud saves, PDF deal sheets, and (on Invest) AI Deal Interpretation that reads the metrics you already generated.
What metrics does the rental property calculator include?
Core screens include monthly cash flow, cap rate, DSCR, cash-on-cash, break-even rent, the 1% rule, and multi-year equity and return charts. The full inventory is in-app; free standalone tools live on the calculators hub.
Does Will It Flow include rent comps or market data?
HUD Fair Market Rent benchmarks by zip and bedroom show on Inputs with one-tap apply. Invest adds Market Intelligence on Outlook — laws, timelines, rent and pricing context, and opportunity signals by zip.
What is AI Deal Interpretation?
An Invest-only dashboard action: one tap produces a plain-English verdict, strengths, risks, and watchouts from the numbers Will It Flow already calculated — the model does not recompute your deal. Unchanged deals load cached summaries instantly.
Stop guessing. Start underwriting.
Free web app — optional Invest for PDFs, BRRRR depth, and AI Deal Interpretation. Mobile apps: join the waitlist below.
Works on desktop and mobile browsers. Create a free account and start analyzing in seconds.
Have an idea? Vote on what we build next on the community feature board.