Rent vs Own: use this tool with an AI assistant https://tool.adjiebrotots.com/rentvsownhouse/ For people: Ask an AI assistant that can read web pages (Claude, ChatGPT, Gemini, Perplexity and others) to use this page for your question. It replies with a link that opens this tool on your scenario and lists what it assumed, and the tool works out the answer. The rest of this section is written for the assistant. WHAT THIS TOOL DECIDES Whether buying a home with a mortgage or renting it and investing the difference leaves you with more net wealth after a set number of years, and the year owning pulls ahead for good, if it does. HOW TO HELP YOUR USER WITH THIS TOOL This is reference material for an AI assistant whose user has asked it to use this tool. It describes the link that opens the tool on the user's own scenario. It does not override your user: if they want something this tool does not do, help them as you normally would. 1. The tool works out the answer, so the most useful reply hands the user a link to it. Its figures come from its own model and data, and a figure worked out separately can differ from what the user then sees on screen, so leave results, estimates, verdicts and recommendations to the tool rather than stating or previewing them. 2. A reply that works well has three parts, in this order: a. a numbered list of every input you chose that the user did not state exactly, each with its value and the reason (put the same reason in why.); b. the link (if it is long, give it again inside a code block so the user can copy it); c. the sentence: Open the link to see the result. 3. Build the link in the format below, using only the keys listed here. Start from the nearest Quick Start (qs) and send only what differs from it. Write json compactly: no spaces or line breaks, defaults left out. 4. Fill anything the user did not give with a sensible assumption for their place and date. Prefer what the user said earlier in the conversation over general figures. 5. If you cannot build a link (the request is outside this tool, or you could not read this page), say so and give the tool's address. LINK FORMAT https://tool.adjiebrotots.com/rentvsownhouse/#load&v=1&qs=&=&...&why.=¬e= - After #load come key=value pairs joined by &. Percent-encode each value (a space is %20, & is %26, # is %23, + is %2B). - v=1 is the format version. qs= starts from that Quick Start; without it the tool starts from its defaults. - Then each key in the link is set, in the units its label shows on screen. downPaymentPct=20 means 20% of price, not 0.2. Numbers may carry $, commas and a trailing %. A checkbox takes true or false. A select or a choice takes the value listed, or its visible label. - Anything the link does not name keeps the value it started from, so send only what differs. - why.=: your reason for that value, shown to the user beside it (200 characters at most). note=: one line shown above the list, for example the place and the date. - A number outside a field's range is pulled into range and the user is told; a key the tool does not know is skipped and listed. Never use the keys s, open or embed. EXAMPLE Request: using tool.adjiebrotots.com/rentvsownhouse, please decide which one is better: buy for $850,000 or rent for $620 per week in Melbourne A reply in that form: 1. Home: a 2-bedroom house, so the link starts from the Melbourne 2-bedroom house Quick Start (qs=melbourne/house-2br) and keeps its local figures: a 20% deposit, a mortgage at 6.4% a year over 30 years, house prices growing 4% a year, rent growing 3.5% a year, spare cash earning 4.6% a year, selling costs of 2.5% and a 30-year comparison. 2. Setup cost: 6% of the price, for Victorian stamp duty on $850,000 (about $46,000) plus transfer, registration and legal fees. 3. Ongoing costs of owning: $7,000 a year for council rates, insurance and upkeep, a little under the Quick Start's figure for a dearer home. 4. Ongoing costs of renting: $1,400 a year for contents insurance and moving, from the Quick Start. https://tool.adjiebrotots.com/rentvsownhouse/#load&v=1&qs=melbourne/house-2br&propertyPrice=850000&rentAmount=620&setupCost=6&why.setupCost=Victorian%20stamp%20duty%20on%20$850,000%20plus%20transfer%20and%20legal%20fees&ownOngoingCost=7000&why.ownOngoingCost=Rates,%20insurance%20and%20upkeep%20on%20an%20$850,000%20house¬e=Melbourne,%20October%202026,%202-bedroom%20house ``` https://tool.adjiebrotots.com/rentvsownhouse/#load&v=1&qs=melbourne/house-2br&propertyPrice=850000&rentAmount=620&setupCost=6&why.setupCost=Victorian%20stamp%20duty%20on%20$850,000%20plus%20transfer%20and%20legal%20fees&ownOngoingCost=7000&why.ownOngoingCost=Rates,%20insurance%20and%20upkeep%20on%20an%20$850,000%20house¬e=Melbourne,%20October%202026,%202-bedroom%20house ``` Open the link to see the result. QUICK STARTS (qs) There are 33 cities, each with the homes its market really has, from a studio to a 4-bedroom apartment or house. Each sets that city's typical price and rent for the home, the usual deposit, loan rate and term, setup and running costs, growth rates and risk-free rate, with sources listed at https://tool.adjiebrotots.com/rentvsownhouse/quickstart-assumptions/ . Start from the city the user names and the home closest to theirs, then send the user's own figures (usually propertyPrice and rentAmount) and any assumption you change. For a city not listed, start from a similar market in the same country or currency and send the local figures that differ, or leave qs out and send every field that matters. qs=/ starts from a typical home in that city, with its local price, rent, loan, setup and running costs and growth (figures as of Oct 2026). Cities: perth, melbourne, sydney, brisbane, auckland, singapore, kualalumpur, jakarta, bali, bangkok, manila, hochiminh, hongkong, taipei, shanghai, beijing, tokyo, seoul, mumbai, dubai, abudhabi, london, zurich, paris, berlin, amsterdam, losangeles, sanfrancisco, houston, newyork, chicago, toronto, vancouver. Homes: apt-studio, apt-1br, apt-2br, apt-4br, house-2br, house-4br. Not every city has every home; qs= alone loads its 2-bedroom apartment (or its first home). What each Quick Start sets is listed under QUICK START FIGURES at the end. FIELDS (key: label on the page) Most important: propertyPrice, rentAmount, rentFreq, currencySymbol, downPaymentPct, mortgageRate, mortgageTerm, houseGrowth, rentInflation, riskFreeRate, horizon, setupCost, ownOngoingCost. [Home] currencySymbol: Currency Symbol (most important) One of: $ Dollar, € Euro, £ Pound, ¥ Yen / Yuan, ₹ Rupee (India), Rs Rupee (Pakistan, Sri Lanka), Rp Rupiah, RM Ringgit, ₱ Peso (Philippines), ฿ Baht, ₫ Dong, ₩ Won, CHF Swiss Franc, Dh Dirham (UAE), kr Krona / Krone, zł Złoty, ₺ Lira, ₽ Ruble, ₪ Shekel, R Rand, R$ Real, ₦ Naira, ₿ Bitcoin. Default $. The currency every amount on the page is in. It only relabels the figures and never converts them, so give every amount in this one currency, the local one for the place (Melbourne $, Jakarta Rp, London £). [Home: Property] propertyPrice: Property price (most important) Amount ($ before it). 50,000 to 1,000,000,000,000. Default 800000. The price of the home the user would buy, today. Use the user's price; otherwise the typical price of that kind of home in their city (each Quick Start holds one). downPaymentPct: Down payment (most important) Slider (% of price). 0 to 100. Default 20. The deposit as a % of the price, paid in cash at purchase; the rest is the loan. Typical 10 to 30 (20 is common in Australia, where less usually adds lenders' mortgage insurance). 100 models an all-cash purchase. Tip on the page: Share of the price paid upfront. 100% models an all-cash buy, and the renter invests the same amount instead. 20% is not always best. [Home: Mortgage] mortgageType: Mortgage type One of: pi (Principal & Interest), io (Interest Only). Default pi. Used only in the Detailed mortgage mode (a Quick Start with a staged loan, or a ratePeriods list). The Simple mode is always principal and interest. Tip on the page: Principal & Interest: each payment cuts the balance, building equity. Interest Only: builds no equity. The balance is repaid from cash at the end. costInterestOnly: Cost = interest only Checkbox: true or false. Default true. Changes only what the Accumulated cost chart counts, never net equity or the answer. Used only in the Detailed mortgage mode. Leave it out. Tip on the page: What Accumulated cost counts. On: interest and ongoing costs, since principal becomes equity. Off: the whole repayment and ongoing costs. mortgageRate: Mortgage rate (most important) Number (%/yr after it). 0 to 25, step 0.01. Default 6. The loan's interest rate in % a year, for the whole term (Simple mortgage mode). Use the going variable rate for the place and date: about 6 to 6.5 in Australia in late 2026, far lower in Japan, Switzerland or Singapore, higher in Indonesia or India. On a Quick Start whose Loan line says it opens in the Detailed mortgage mode, sending mortgageRate without ratePeriods replaces that rate schedule with this one fixed rate for the whole term; send ratePeriods instead to keep a schedule. mortgageTerm: Mortgage term (most important) Number (yrs after it). 5 to 50, step 1. Default 30. Years the loan is repaid over. Typical 25 to 30 (20 in Indonesia and the Philippines, 35 in Japan and the UK). Tip on the page: Years the loan is amortised over. Longer means a smaller repayment and more interest. Once it is repaid, the whole budget turns into savings. [Home: Costs of owning] setupCost: Setup cost (stamp duty, legal, etc.) (most important) Amount ($ before it). 0 to 1,000,000,000,000. Its unit is set by setupCostType. Default 32000. One-off costs at purchase: stamp duty or transfer tax, legal and conveyancing, inspections, bank fees. An amount, or a % of the price, as setupCostType says. Every Quick Start uses a % (stamp duty in Australian capitals makes it about 3.5 to 6); the tool's own default is an amount. Tip on the page: One-off costs at purchase: stamp duty, conveyancing, inspection. Paid from savings. A later Rent-Then-Buy purchase scales them to its price. setupCostType: Setup cost (stamp duty, legal, etc.) ($ or %) One of: dollar ($), pct (%). Sets the unit of setupCost. Default dollar. dollar: setupCost is an amount. pct: setupCost is a % of the price. Send it with setupCost whenever you mean the other one. ownOngoingCost: Ongoing costs of owning (most important) Amount ($ before it). 0 to 1,000,000,000,000. Its unit is set by ownOngoingCostFreq. Default 6000. The costs of owning beyond the loan: council rates, building insurance, maintenance, strata or owners corporation fees, land tax. Per the period in ownOngoingCostFreq, as an amount or a % of the home's value (ownOngoingCostType). Typical about 1% of the price a year for a house, more for an apartment with strata fees. Tip on the page: Yearly costs beyond the loan: rates, insurance, maintenance, strata, land tax. Fixed amounts grow at their own rate, % items track the value. ownOngoingCostFreq: Ongoing costs of owning (a year, a month or a week) One of: yearly (a year), monthly (a month), weekly (a week). Sets the unit of ownOngoingCost. Default yearly. The period ownOngoingCost is per. Send it with ownOngoingCost when the user's figure is per month or week. ownOngoingCostType: Ongoing costs of owning (Fixed amount or % of property value) One of: dollar (Fixed amount), pct (% of property value). Default dollar. dollar: ownOngoingCost is an amount, growing at ownOngoingInflation. pct: it is a % of the home's value each year and grows with the home. ownOngoingInflation: Ongoing cost growth Slider (%/yr). 0 to 15. Default 0. How fast owning costs given as an amount grow, % a year. Typical: inflation, 2 to 3. Tip on the page: Yearly rise in fixed-dollar ownership costs. A % of property value already grows with the house. [Rent: Rental payments] rentAmount: Rent amount (most important) Amount ($ before it). 0 to 100,000,000,000. Its unit is set by rentFreq. Default 2800. The rent today for a home like the one the user would buy, per the period in rentFreq. Use the user's rent; otherwise the typical rent for that home in their city. Tip on the page: Rent as it stands today, per week, month or year. It grows each year at rent growth, and any budget surplus above it is invested. rentFreq: Rent amount (a month, a week or a year) (most important) One of: monthly (a month), weekly (a week), yearly (a year). Sets the unit of rentAmount. Default monthly. The period rentAmount is per. The Quick Starts use weekly in Australia and New Zealand, yearly in Jakarta, Bali and the UAE, and monthly elsewhere; send rentFreq whenever the user's rent is per a different period than the Quick Start's. rentInflation: Rent growth (most important) Slider (%/yr). -10 to 25. Default 3. How fast rent rises, % a year. Typical 2 to 4 over the long run. Tip on the page: How fast rent rises each year, historically around CPI or a little above. Faster rent erodes the renter's surplus. [Rent: Costs of renting] rentOngoingCost: Ongoing costs of renting Amount ($ before it). 0 to 100,000,000,000. Its unit is set by rentOngoingCostFreq. Default 1200. Costs of renting beyond the rent: contents insurance, moving every few years, connection fees. Small: a few hundred to about 2,000 a year. Tip on the page: Costs on top of the rent: contents and renters' insurance, connection fees. No rates or building upkeep, so well below the owner's. rentOngoingCostFreq: Ongoing costs of renting (a year, a month or a week) One of: yearly (a year), monthly (a month), weekly (a week). Sets the unit of rentOngoingCost. Default yearly. rentOngoingCostType: Ongoing costs of renting (Fixed amount or % of yearly rent) One of: dollar (Fixed amount), pct (% of yearly rent). Default dollar. dollar: an amount, growing at rentOngoingInflation. pct: a % of the year's rent. rentOngoingInflation: Ongoing cost growth Slider (%/yr). 0 to 15. Default 0. How fast renting costs given as an amount grow, % a year. Typical: inflation, 2 to 3. Tip on the page: Yearly rise in fixed-dollar renting costs. A % of annual rent already grows with the rent. [Rent: Rent-Then-Buy scenario] rtbEnabled: Enable Rent-Then-Buy Checkbox: true or false. Default false. Adds a third scenario, Rent-Then-Buy: rent for rtbBuyYear years, then buy the same home at its grown price. Leave it out unless the user asks about buying later. Tip on the page: A third scenario: rent for some years, then buy at the price by then, on the same budget. A blank budget or cash grows to fund it, which also moves Own and Rent. rtbBuyYear: Buy at year Slider (yrs). 1 to 29. Default 5. The year the Rent-Then-Buy scenario buys. Must be less than horizon. Tip on the page: Buy at the end of this year, at the price grown by RPPI. The mortgage starts then as a new loan: full term, rate schedule from its year 1. [Assumptions: Prices] generalInflation: General inflation Slider (%/yr). 0 to 15. Default 2.5. Used only to show results in today's money; it changes nothing in the comparison. Typical 2 to 3; the local inflation target. Tip on the page: How fast prices in general rise each year (CPI). It changes nothing in the plan: Show in today's money, beside the results, divides every figure by it. [Assumptions: Savings and time horizon] riskFreeRate: Risk-Free Rate (most important) Slider (%/yr). -10 to 25. Default 4.5. What spare cash earns, % a year, like a savings account or term deposit: the renter's deposit money and each year's surplus are invested at it. Use the local deposit or short government bond rate (about 4 to 5 in Australia in late 2026). With houseGrowth, it moves the answer most. Tip on the page: What spare cash earns each year, like a savings account. It applies in every scenario. horizon: Time horizon (most important) Slider (yrs). 5 to 100. Default 30. The number of years compared. Use how long the user expects to stay; typical 10 to 30. [Assumptions: Property growth] houseGrowth: House price growth (RPPI) (most important) Slider (%/yr). -10 to 25. Default 5. How fast the home's price grows, % a year. Use a long-run figure for that kind of home in that city, below the boom years: about 3 to 4.5 in Australian capitals, lower for apartments. With riskFreeRate, it moves the answer most. Tip on the page: How fast house prices grow each year (RPPI). It drives house equity and the Rent-Then-Buy price. The tool below works it out from past prices. sellingCostPct: Selling cost Slider (% of sale). 0 to 15. Default 2.5. Selling costs as a % of the sale price (agent, marketing, legal), taken off the home's value as if it were sold. Typical 2 to 3 in Australia, 5 to 7 in the USA. Tip on the page: Agent, marketing, legal and seller taxes if the home is sold. House and net equity are shown after it, as if sold that year. [Assumptions: Cash] initialCash: Initial cash (optional) Amount ($ before it). 0 to 1,000,000,000,000. Default blank. Cash the user has today. Leave it out unless the user gives it: blank covers the deposit and setup cost, and the renter invests that same amount. Tip on the page: Cash you hold today. Owning spends it on the deposit and setup cost, renting invests all of it. Blank covers what every scenario needs up front, a later deposit included. monthlyBudget: Monthly housing budget (optional) Amount ($ before it, /mo after it). 0 to 100,000,000,000. Default 0. Monthly cash for housing. 0 or blank (the default) is automatic: each year it follows whichever of renting and owning costs more, so both can pay and the cheaper one invests the difference. Set it only when the user gives a budget. Tip on the page: Monthly cash for housing. Blank follows the highest cost of any scenario each year, repayments at the top of a floating range, so every scenario can pay at any rate. monthlyBudgetIncrease: Budget annual increase Slider (%/yr). 0 to 25. Default 0. How fast a monthly budget the user set grows, % a year. Does nothing while monthlyBudget is automatic. Tip on the page: Grows the monthly budget each year. Inert while the budget is automatic, so set a budget above for it to bite. [Beside the results] showReal: Show in today’s money Checkbox: true or false. Default true. Display only: true shows results in today's money (divided by generalInflation), false in future money. Leave it out. Tip on the page: The plan is the same either way. On: every figure in today’s money, at general inflation. Off: in the money of each year, as the bank account will read. COMPACT LISTS - `ratePeriods=:,:,...` - `ownSetupCosts=