Run the numbers on any popular rent-versus-buy calculator and you'll get a tidy answer: buy if you plan to stay five years, rent if you don't.
The problem is that those tools quietly bury the assumptions doing all the heavy lifting.
Zillow's calculator, for instance, defaults to a 3% annual home appreciation rate.
In a market where national home prices fell year-over-year as recently as 2023, that default isn't a forecast — it's a sales pitch.
Change that single number to 1% and a five-year breakeven can stretch past a decade.
Most calculators use 1% of the home's value per year, which sounds reasonable until you own a house.
A $400,000 home means $4,000 annually, or about $333 a month.
Those aren't monthly line items, so renters comparing a $2,200 rent check to a $1,900 mortgage payment never see them coming.
Then there's the opportunity cost nobody models.
A 20% down payment on that $400,000 house is $80,000.
Parked in a high-yield savings account at 4.5%, that's $300 a month in interest — money that vanishes the moment it becomes equity in a house you can't spend.
The portals that run the calculators also sell ads to lenders and agents.
That's not a conspiracy, it's just business.
But it means the tool isn't neutral, and treating it like a neutral referee is how people end up house-poor.
Build your own spreadsheet with three scenarios — pessimistic, realistic, optimistic — and run each one.
Include property taxes (which reset after purchase in many states), insurance, HOA dues, closing costs on both ends, and the realtor's 5-6% cut when you sell.
Most importantly, stress-test the timeline.
If you'd need to move for a job, a breakup, or a sick parent within three years, the transaction costs alone — often 8-10% of the purchase price — will eat any equity you built.
In many markets, buying and holding for a decade still builds wealth that renting can't match, especially with a fixed-rate mortgage in a world of rising rents.
The point is that the answer should come from your numbers, not a widget's defaults.
The next time a calculator spits out a confident verdict in three seconds, ask what it assumed to get there.
If the tool won't show you its work, you're not reading an analysis.
Final Thoughts
You're reading marketing with a decimal point.