Paid script
Home and car cost tools (Python script)
Three big-purchase questions in one file: what can I afford, is renting or buying better over my time horizon, and what will this car really cost.
Paid script
Home and Car Cost Python script
Buy this script on its own for $19, one time. No membership needed. It runs on your own computer and nothing you enter leaves it. Read how it works and the questions below first.
The Personal Finance Suite includes this and 3 more tools for $29. Members get this included. See the membership or sign in. Already bought it? Email me my access link.
How it works
How it works
Afford finds the largest home price that keeps housing under 28% and total debt under 36% of gross income, counting taxes, insurance and mortgage insurance. Rent versus buy compares your net worth as an owner (after selling costs) with a renter who invests the down payment and the monthly difference, and shows the year buying overtakes renting. Car adds the loan, insurance, fuel and maintenance and subtracts resale value to give the true cost per month and per mile. Every assumption can be changed with a flag.
FAQ
About this calculator
Is the affordability number a mortgage approval?
No. It uses common rules of thumb. Lenders also look at credit, savings and other factors, and local taxes and insurance vary.
Why does rent versus buy depend so much on assumptions?
Appreciation, rent growth, investment return, upkeep and how long you stay move the answer a lot. The script prints its assumptions and lets you change each one.
Is this financial or real-estate advice?
No. It is a planning tool for general information.
Is anything saved?
No. The math runs in your browser and nothing you enter is sent to us.
Is this tax or financial advice?
No. It is a calculator for general information. Check the numbers against your own records, and ask an accountant before you act on them.
Related: simple interest calculator, compound interest calculator. See all free tools. More free tools: HOA dues per unit calculator, Deadhead percentage and revenue per mile calculator, Short-term rental break-even occupancy calculator, or see all free tools.
Free
Month-End Close Checklist (PDF)
The five-day close, one page to print. Enter your email and we send a link to confirm it is yours, then the download. We may email you about new toolkits, and every email has an unsubscribe link.
General information, not tax or legal advice. How we write and check our tools.