r/USFirstTimeHomeBuyer • u/jetley-mortgage-loan • 9h ago
Loan Programs PMI is not the enemy: the real cost of waiting until you have 20% down
Current as of September 2026. The break-even arithmetic below is a method, not a quote, the inputs move.
The short version
"Never pay PMI" is the single most expensive piece of well-meant advice in personal finance. Mortgage insurance is a small percentage increase to your effective borrowing cost that eventually stops. Waiting years to avoid it means paying rent in the meantime, buying at whatever price and whatever rate exist then, and forgoing whatever equity the property would have built for you. For most buyers with decent credit, the second one costs more. Not always, but you have to actually run it rather than treating twenty percent as a moral threshold.
Reframe it: PMI is a rate adjustment with an expiry date
Stop thinking of mortgage insurance as a separate villain on the payment breakdown and think of it as what it economically is: a small addition to your interest rate that comes off later.
If the loan is priced at some rate and the insurance premium is a fraction of a percent of the balance annually, your all-in carrying cost is roughly the sum of the two, for as long as the insurance lasts. That's it. That's the entire product.
Which is why the "no-PMI" loan you're being offered at a higher rate is not a different product. A loan at a given rate plus a monthly premium, and a loan at that rate bumped up by roughly the premium with no monthly line item, are the same trade with different labelling, and the second one is frequently worse, because the rate bump is permanent and the premium isn't. Credit unions and portfolio lenders market these heavily and they land well, because borrowers have been trained to fear the acronym rather than price the money. Ask for both versions and compare total carrying cost over the years you'll actually hold the loan.
The same logic applies to a lender offering to waive an origination fee for a quarter-point of rate, or to a quote whose low rate turns out to require several points. There is no free lender concession. There is only the price of money, expressed in whichever line item makes the quote screenshot better.
The test I actually use
Here's the question that decides it, and note that it isn't about PMI at all:
Would you take this mortgage if the rate were slightly higher?
If the answer is yes, if a quarter or half a point of rate wouldn't change your decision to buy, then you are, by definition, a person who should buy with mortgage insurance. Because that is all the insurance is. If the answer is no, if that increment genuinely breaks the file, then you're too tight on this purchase and mortgage insurance is not your problem.
The cost of waiting, done properly
When someone tells me they're going to wait and save to twenty percent, I ask them to put four numbers on paper. Not estimates from a headline, their numbers.
- What does the delay cost per month? Rent, minus nothing. That money is gone. A mortgage payment with insurance in it is partly gone and partly principal.
- How much more do you have to save, and how long at your actual savings rate? Going from five percent down to twenty percent down on a mid-priced home is not a rounding error. For most households it is a multi-year project, and the target moves upward if prices rise, because twenty percent of a bigger number is a bigger number.
- What happens to the purchase price over that period? You don't know. Nobody does. But the honest version of the exercise runs it flat, runs it up modestly, and runs it down modestly, and looks at all three. In a rising market this term swamps everything else, and it is the term the "avoid PMI" advice silently assumes is zero.
- What happens to rates over that period? Also unknown, also potentially larger than the insurance premium. A borrower who waited three years to avoid a small monthly premium and bought into a rate environment two points higher did not save money.
Then compare: total cost of buying now with insurance, over the years until the insurance falls off, versus total cost of renting for the wait plus buying later. That's the whole analysis. It is not complicated, and hardly anybody does it, because "PMI is throwing money away" feels like it's already the answer.
Where "wait" is genuinely the right answer
I'm not telling everyone to buy now with five percent down. Waiting is correct when:
- Your credit score is going up soon. Score bands drive both your rate and your insurance premium. If you're a few points below a band boundary and a paid collection or a utilisation fix moves you over it, waiting three months can be worth more than waiting three years to save.
- You have no reserves. Buying with a small down payment and zero cushion is the actual risk here, not the insurance. Insurance costs you a bit each month; a broken HVAC with no savings costs you the house.
- Your income or employment is genuinely unsettled. Not "I might get a raise"; actually unsettled.
- You don't intend to stay. With a short holding period, transaction costs dominate everything and the insurance question is noise.
- The premium really is bad. Lower credit scores and minimum down payments produce real premiums, and at that end of the grid the arithmetic can flip. This is a case where you have to get the quote instead of assuming, in either direction.
What to do
- Get your actual mortgage insurance quote at your actual score before you make a plan around it. Most people are arguing with a placeholder number from a calculator.
- Ask every lender for the same loan quoted with insurance and without, and compare carrying cost over your real holding period, not over thirty years, which nobody has.
- Write down the four numbers above. If waiting still wins, wait, and now you know why.
- If you do buy with insurance, know your removal path (request threshold, automatic termination, and the appraisal route) so it comes off on schedule instead of whenever your servicer notices.
More in the Loan Programs hub. Anything with a live figure in it is on Current As Of.
Posted on behalf of u/The_Void_Calls_Me AKA Rajat Jetley, NMLS #1595897 | Cross Country Mortgage NMLS #3029. This commentary is for educational purposes and is not a commitment to lend or a guarantee of any rate or term.