📊 How This Calculator Works
This tool models two parallel financial paths over your chosen time horizon and compares your total estimated after-tax net worth in each scenario — not just monthly payments, but total real wealth including opportunity costs, taxes, maintenance, and the cost of your time.
For prospective buyers: (1) Renting while investing the savings vs. (2) Buying a home and building equity.
For existing owners: (1) Selling your home, investing the equity, and renting vs. (2) Staying in your home and continuing to build equity. Select "I own and I'm reconsidering" in Question 1 to activate owner mode — input labels, results, and the AI Summary all adapt to your situation.
The Core Question: After X years, are you wealthier after tax having rented + invested, or having owned? For existing owners: are you wealthier selling and investing, or staying and holding? The answer depends entirely on your specific numbers — there is no universal right answer.
🗂️ The Seven Tabs
Inputs — All input fields, the situation questionnaire, live scorecard, What-If sliders, and Email My Results. Every value updates results instantly.
Results — Side-by-side after-tax net worth, break-even timeline, monthly cost bar chart, and Price-to-Rent ratio with 60-metro reference grid.
Tax & Graph — Deduction analysis, per-bucket portfolio tax breakdown, owner home sale breakdown, and the 30-year net worth trajectory chart.
Mortgage — PITI breakdown, 8-metric summary, and full 360-month amortization table.
True Costs — All hidden ownership costs, time tax breakdown, and 30-year repair timeline.
✨ AI Summary — Personalized written analysis powered by Claude AI. Requires completing the 5-question profile. Customize tone, focus, and length before generating. Copy to clipboard or print as a branded PDF.
How It Works — This tab. Explains the math, concepts, and when each path wins.
🎯 The Situation Questionnaire
Before running numbers, a 5-question profile appears above the inputs. It asks about your current situation, how long you plan to stay (or have owned), what matters most (or what's driving you to sell), your biggest hesitation, and your risk tolerance.
The questionnaire is not a gate — you can skip it and use the calculator freely. But completing it unlocks the ✨ AI Summary. If you select "I own and I'm reconsidering," the entire app adapts: input sections become "Your Current Home & Mortgage" and "If You Sold & Rented Instead," questions shift to owner context (how long owned, hesitation about selling), and results show "Selling Wins" vs "Staying Wins."
Why it matters: The AI Summary combines your profile answers with your actual numbers to generate advice specific to your situation — not generic talking points. For owners, it frames the analysis as sell-and-rent vs. hold-and-stay.
✨ AI Summary
Once your profile is complete, the AI Summary tab generates a personalized written analysis using Claude (by Anthropic). Control three settings before generating:
Tone: Advisor · Plain English · Direct · Data-Driven
Focus: Give me a verdict · Show both sides · Address my concern · Focus on my timeline
Length: Short (2–3 paragraphs) · Standard (4–5 paragraphs) · Detailed (comprehensive)
Optional toggles add "What to watch out for" and concrete next steps. For existing owners, the AI reframes the analysis as sell-and-rent vs. hold-and-stay — not a first-time buy decision. Copy to clipboard or print as a branded PDF with your agent's contact info.
Important: The AI uses only the numbers from your inputs — it does not estimate or invent figures. This is for guidance only and does not constitute financial advice.
🎚️ What-If Sensitivity Sliders
Below the main inputs, three sliders let you explore how the verdict shifts as key assumptions change — home appreciation rate, investment return, and analysis period. Drag a slider and the scorecard updates instantly.
Important: Sliders explore scenarios without changing your saved inputs. The Reset button restores your actual numbers. Use them to answer "what if rates drop?" or "what if I stay longer?" without losing your baseline.
📍 Price-to-Rent Ratio
The Results tab auto-calculates your market's Price-to-Rent ratio (home price ÷ annual rent). The ratio tells you at a glance whether your market leans toward buying or renting:
Under 15 — Strong buy signal. Owning is cheap relative to renting.
15–20 — Neutral. Both paths are competitive.
20–25 — Renting-leaning. Prices are elevated relative to rents.
Over 25 — Strong rent signal. Buying is expensive relative to renting.
A 60-metro reference grid shows how your ratio compares to cities across the US.
🔗 Shareable URL & Saving
The 🔗 Share button in the nav encodes all 36 of your inputs as URL parameters. Copy the link and bookmark it — that link IS your saved scenario. Send it to a partner, advisor, or agent. Open it later and every field is restored exactly as you left it.
No account needed. Your inputs never leave your browser — the shareable URL is the only "save" mechanism. The AI Summary is also cached locally for 24 hours so you don't have to regenerate if you revisit.
⚡ Quick-Fill Listing Bar
The collapsed bar just above the input accordions lets you enter a listing price, down payment %, rate, and HOA — then click Apply. It pre-fills the four most common fields at once and shows a live P&I preview. Useful when you're evaluating a specific property from a listing.
📐 The Math — Pre-Tax
Renter/Seller Wealth = Future value of lump sum + Future value of monthly investments
FV = P×(1+r)^n + PMT×[(1+r)^n – 1]/r
For buyers: P = down payment + closing costs (money freed up by renting). For owners who sell: P = equity minus selling fees (net proceeds invested on Day 1).
Owner Wealth (buyer mode) = Future home value × (1 – sell%) – Remaining balance – Closing costs
Owner Wealth (stay mode) = Future home value × (1 – sell%) – Remaining balance (no closing costs — you already own)
Owner NW = FV_home×(1–sell%) – balance – closing (buyer) or – 0 (owner)
🧾 The Math — After-Tax
Renter after-tax NW depends on how the portfolio is split across three buckets:
Taxable: (value – gains×LTCG_rate)
Roth: value (zero tax ever)
Traditional: (value – value×eff_rate) + contrib_savings
Owner after-tax NW applies the primary residence capital gains exclusion first ($250K single / $500K married), then taxes any remaining gain at the long-term rate. The mortgage interest deduction benefit (if itemizing beats standard) is added back.
⚠️ The #1 Rule: You Must Actually Invest
Every financial advantage of renting — or selling and renting — hinges on one thing: you must actually invest the money. Almost nobody does it consistently.
The brutal math: If you rent and spend instead of invest, you build zero equity and zero wealth. Homeownership forces savings. Renting only wins if you replicate that discipline — automatically, every month, without exception. For owners considering selling: if you'd spend the equity rather than invest it, staying wins every time.
Set up auto-transfer on rent day. Use broad index funds. Treat it like a utility bill.
🧾 Tax Analysis — Deductions
The calculator automatically determines whether itemizing beats the standard deduction ($14,600 single / $29,200 married in 2024). It uses whichever is larger for your specific inputs.
Post-TCJA reality: Since 2018, most homeowners — especially those with mortgages under ~$400K — are better off with the standard deduction. The calculator shows which wins for your exact numbers.
🏠 Primary Residence CGE
Up to $250,000 of home appreciation is tax-free when you sell (single), or $500,000 if married filing jointly — as long as you lived there as your primary residence for 2 of the last 5 years.
Why this matters: On a $400K home at 3.5%/yr, after 10 years the gain is ~$163K — fully excluded. The exclusion often makes the owner's capital gains tax bill zero, and is a major reason buying can win after-tax even when it loses pre-tax.
📊 Portfolio Tax Buckets
Taxable brokerage: Gains taxed at long-term capital gains rate (0%, 15%, or 20%) at sale.
Roth IRA / Roth 401k: After-tax contributions. All growth and withdrawals completely tax-free.
Traditional 401k / IRA: Pre-tax contributions save at your marginal rate now. Withdrawals taxed at effective rate in retirement.
Strategy note: A portfolio 70%+ Roth significantly improves the renter's after-tax outcome — sometimes enough to swing the verdict.
📉 When Buying / Staying Wins
For buyers: Owning tends to generate greater after-tax wealth when: you stay 7+ years, your market appreciates strongly, itemizing is worthwhile, your investment discipline is weak, and/or the primary residence CGE shelters most of your gain.
For owners considering selling: Staying wins when: you have a low locked-in mortgage rate, strong local appreciation, significant CGE shelter remaining, and/or you wouldn't realistically invest the sale proceeds with discipline.
🏢 When Renting / Selling Wins
For buyers: Renting + investing tends to win when: you may move within 5–7 years, price-to-rent ratios are high, your portfolio is mostly Roth, and you actually invest the difference every month without exception.
For owners considering selling: Selling wins when: your equity is large and could earn strong returns in the market, carrying costs (taxes, insurance, maintenance) are high relative to rent, and/or your home's appreciation potential is modest. The key assumption: you must invest 100% of the net proceeds and maintain monthly investment discipline.
Non-financial factors matter too: This calculator measures money, not happiness. Ownership offers stability and roots. Renting offers flexibility and zero maintenance burden. Only you can weigh these.
🔧 The 1% Maintenance Rule
Budget 1% of home value per year for maintenance. Older homes: 2–3%. Covers HVAC ($3–15K), roof ($8–25K), water heater ($1–3K), appliances, plumbing, and landscaping. The rule smooths lumpy real-world costs into a consistent annual average.
The sneaky reality: Most years you spend very little. Then one year the furnace AND the roof AND the water heater fail. Budget as though it will happen — because over 30 years, it always does.