Why paying 20% down and a 5% one-time payment is better than 25% down - Reddit scenario
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By Editorial team
A user on r/Mortgages asked whether they should pay 25% down at closing or put 20% down and pay 5% of the purchase price as an additional one-time payment at the first monthly payment. These options appear to be exactly the same to the borrower, but how does it affect their payments? Their loan officer said there is no prepayment penalty.
On a $500,000 home in our tool, the 20% down with 5% one time payment scenario ends with about $28,960 less total interest over 30 years than the 25% down tab. Why is this? It is because the larger scheduled payment on the loan when you finance 80% of the price pays principal faster after the one-time payment posts. As long as they can afford the slightly higher monthly payment, they would save money in the end by going with the 20% down and 5% one-time payment.
The scenario modeled
Two US conventional tabs, same May 2026 start, 30-year amortization, 6.00% fixed, no private mortgage insurance (PMI) (20% and 25% down), and no taxes or insurance so the comparison stays on principal and interest (P&I) only. The 20% down with 5% one time payment tab adds $25,000 to principal on the first scheduled payment (5% of $500,000). You can open the exact tabs with the calculator button at the end of this article.
| Input | 25% down | 20% down with 5% one time payment |
|---|---|---|
| Purchase price | $500,000 | $500,000 |
| Down at closing | $125,000 (25%) | $100,000 (20%) |
| Starting loan | $375,000 | $400,000 |
| Rate / term | 6.00% / 30 yr | 6.00% / 30 yr |
| First-payment extra to principal | $0 | $25,000 (5% of price) |
| First month P&I only | $2,248 | $2,398 |
| First month total (with one-time extra) | $2,248 | $27,398 |
The findings
After the first payment, both paths land on a remaining balance near $374,600, but the 20% down with 5% one time payment tab keeps the higher required monthly P&I ($2,398 versus $2,248) for the rest of the loan because you still closed on the full 80% loan amount. That larger fixed payment applies more to principal every month, so total interest over 30 years comes in lower on that tab in this model even though you wait two weeks of calendar time to move the extra $25,000 (the thread asked about cash still in a certificate of deposit at closing).
| 25% down | 20% down with 5% one time payment | Difference | |
|---|---|---|---|
| Scheduled P&I (before extra) | $2,248/mo | $2,398/mo | $150/mo more than 25% down |
| Modeled total interest (30 yr) | $434,393 | $357,653 | $76,740 less interest than 25% down |
| Cash to housing in first month | $125,000 at close | $100,000 at close + $25,000 in month 1 | Same $125,000; different timing |
US context
Most US households either own a home or hope to, so questions about down-payment timing are mainstream. The U.S. homeownership rate was 65.6% in the fourth quarter of 2024 (see source note below). We also assumed no prepayment penalty for extra principal, as the Reddit author said their loan officer confirmed.
Source: U.S. Census Bureau, "Quarterly Residential Vacancies and Homeownership, Fourth Quarter 2024," published January 2025, accessed April 2026. The report states the U.S. homeownership rate was 65.6% in the fourth quarter of 2024. URL: https://www.census.gov/housing/hvs/files/currenthvspress.pdf
When this comparison applies - and when it doesn't
Use this comparison when: You are choosing between bringing the full down payment to closing versus staging part of it a few weeks later, your loan allows large first-month principal payments, and you are comfortable with the higher monthly payment on the smaller-down path.
It does not apply when: A lower down payment triggers PMI that the 25% down would avoid, when you need the lower payment for cash-flow reasons, or when investment returns on the deferred cash clearly beat your after-tax mortgage cost after early-withdrawal penalties on a certificate of deposit. It also does not replace a conversation with your lender about how the first payment will be applied.
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Frequently asked questions
- Is putting 20% down and 5% of the price on the first payment the same as 25% down at closing?
- Not exactly. You pay an extra month of interest on the larger starting loan before the extra principal posts, and your required principal and interest (P&I) payment stays at the payment for your original 20% down loan size even after the balance drops. In our modeled $500,000 example at 6%, that higher payment forces more principal each month than the 25% path, which is why lifetime interest can end up lower even though the starting balance was larger.
- Does a one-time principal payment on day one work like a bigger down payment?
- Economically it moves your balance toward where a higher-down loan would have started, but your loan amount at closing is still the larger 80% figure, so your contractual payment does not automatically drop the way it would if you had borrowed less from the start. Always match the structure to what your lender actually allows on the first statement.
- Should I break a certificate of deposit early to put 25% down instead of waiting two weeks?
- This article does not model early-withdrawal penalties or interest on the deposit. If you cash it out early for a fee, add that cash cost to the 25% side. If the rate you earn on the deposit is higher than your after-tax mortgage rate, keeping it and sending the one-time principal payment a few weeks later can look better on paper, but only if the math on fees, timing, and liquidity still works for you.
- Will my loan servicer apply a large first payment to principal the way the calculator assumes?
- Confirm in writing how one-time payments are applied and whether any must go to escrow or fees first. The CFPB recommends keeping records of how extra payments are credited. If part of the check is misapplied, the outcome will not match a clean principal-only add-on.