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Model buying a house or car

How do I model buying a house or a car in a scenario?

How-to
3 min
Verified · Jul 17, 2026

When you want to see what a home or vehicle purchase would do to your money, the Scenario Tester has two shortcuts: Buy a House and Buy a Vehicle. Each one asks for a few numbers and then adds three linked items to your scenario at once — an asset for what you're buying, an amortized loan for what you'd borrow, and a monthly payment bill.

An amortized loan is one you pay off in equal monthly payments over a set number of months, with each payment covering part interest and part principal.

Before you start

  • Purchase bundles live inside the Scenario Tester, which is free for the account owner and their spouse.
  • Open or create a scenario first — the bundle adds its items to whatever scenario is active. See Test a what-if scenario.

Steps

  1. In the Scenario Tester, open or create a scenario.
  2. In the right panel, Add to Scenario, click Buy a House or Buy a Vehicle.
  3. Enter a Name (for example, "FL House" or "New Truck").
  4. Enter the Purchase Price and the Down Payment.
  5. Set the Interest Rate. It starts at 6.5% for a house and 7.0% for a vehicle — change it to your rate.
  6. Set the term — Term (years) for a house (starts at 30) or Term (months) for a vehicle (starts at 60).
  7. Check the This will add to your scenario preview — it shows the asset, the loan, and the estimated monthly payment. Click Add House or Add Vehicle.

What the bundle creates

For a house named "FL House", the bundle adds:

  • Asset — FL House: its value equals the purchase price.
  • Debt — FL House Mortgage: the loan amount, which is the purchase price minus the down payment.
  • Bill — FL House Payment: the amortized monthly payment, set to Monthly and marked as a need.

A vehicle bundle works the same way, except the debt is named "… Loan" instead of "… Mortgage". The monthly payment comes from a standard amortized-loan formula using your price, down payment, interest rate, and term. You can check the same math with the Loan Payment Calculator.

Good to know

  • The three items stay grouped. Edit the bundle to change any number and all three items are rebuilt. Remove the bundle and all three go away together — you can't edit or delete the asset, loan, or payment on their own.
  • Only two bundles exist. Buy a House and Buy a Vehicle are the only purchase templates. For anything else, add items individually with Add Item.
  • Bundles cover the basics only. They use purchase price, down payment, interest rate, and term. There are no fields for closing costs, PMI, HOA fees, taxes, insurance, or a trade-in — add a separate bill if you want to include those.
  • It's still point-in-time. Like the rest of the Scenario Tester, a purchase bundle compares your money today against today with the purchase applied. It doesn't project the loan's payoff over the years — the retirement projection handles long-term loan payoff instead.

FAQ

What does a purchase bundle create?

Three linked items at once — an asset for the purchase price, a debt for the loan (purchase price minus down payment), and a monthly payment bill marked as a need. They're grouped so you can edit or remove them together.

How is the monthly payment figured?

From a standard amortized-loan formula using your purchase price, down payment, interest rate, and term. An amortized loan is one you pay off in equal monthly payments over a set number of months.

Are there bundles for anything besides a house or a car?

No. The only two purchase bundles are Buy a House and Buy a Vehicle. For anything else, add items one at a time with Add Item.

Can I set closing costs, PMI, or a trade-in?

Not in a bundle. A bundle uses purchase price, down payment, interest rate, and term only. You can add a separate bill or adjust the numbers to approximate other costs.

Does this actually buy anything or change my real data?

No. A bundle only adds hypothetical items to the scenario for comparison. Your real assets, debts, and bills are untouched.

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PiggySize is a planning tool, not a financial advisor. Help articles are educational — projections and examples are estimates based on the numbers you enter, not financial, tax, or investment advice.