Free home-buying planning tool
Should more cash go down—or stay invested?
Compare a smaller down payment and an initial brokerage investment with putting more cash toward a 30-year fixed mortgage. Change every planning assumption and see the tradeoffs update instantly.
1. Purchase setup
Make the home scenario yours
2. Model assumptions
Set the costs and return
The default model uses a 10% nominal pre-tax return, 0.5% annual PMI, and a 78% estimated PMI removal point. All are editable planning assumptions, not forecasts or lender quotes.
See the tradeoff over time
How the two paths compound.
The green line is the initial cash invested in a brokerage account. The gold line is the future value of the added P&I and modeled PMI from choosing the smaller down payment.
Explore the range
Compare down-payment choices.
Every row uses the same 30-year mortgage, cash-available, PMI, and portfolio-return assumptions above. Your selected down payment is highlighted.
| Down payment | Down % | Loan | Initial P&I + PMI | Invest now | 30-year brokerage value | Future value of extra cost | Net advantage |
|---|---|---|---|---|---|---|---|
| $5,000 | 2.7% | $180,000 | $1,236.50 | $15,000 | $261,741 | $229,318 | +$32,423 |
| $6,000 | 3.24% | $179,000 | $1,229.63 | $14,000 | $244,292 | $213,962 | +$30,330 |
| $7,000 | 3.78% | $178,000 | $1,222.76 | $13,000 | $226,842 | $198,582 | +$28,260 |
| $8,000 | 4.32% | $177,000 | $1,215.89 | $12,000 | $209,393 | $183,246 | +$26,147 |
| $9,000 | 4.86% | $176,000 | $1,209.02 | $11,000 | $191,943 | $167,919 | +$24,025 |
| $10,000 | 5.41% | $175,000 | $1,202.15 | $10,000 | $174,494 | $152,575 | +$21,919 |
| $11,000 | 5.95% | $174,000 | $1,195.28 | $9,000 | $157,045 | $137,244 | +$19,800 |
| $12,000 | 6.49% | $173,000 | $1,188.41 | $8,000 | $139,595 | $121,951 | +$17,644 |
| $13,000 | 7.03% | $172,000 | $1,181.54 | $7,000 | $122,146 | $106,648 | +$15,498 |
| $14,000 | 7.57% | $171,000 | $1,174.68 | $6,000 | $104,696 | $91,361 | +$13,336 |
| $15,000 | 8.11% | $170,000 | $1,167.81 | $5,000 | $87,247 | $76,090 | +$11,157 |
| $16,000 | 8.65% | $169,000 | $1,160.94 | $4,000 | $69,798 | $60,835 | +$8,962 |
| $17,000 | 9.19% | $168,000 | $1,154.07 | $3,000 | $52,348 | $45,599 | +$6,750 |
| $18,000 | 9.73% | $167,000 | $1,147.20 | $2,000 | $34,899 | $30,380 | +$4,519 |
| $19,000 | 10.27% | $166,000 | $1,140.33 | $1,000 | $17,449 | $15,180 | +$2,269 |
| $20,000 | 10.81% | $165,000 | $1,133.46 | $0 | $0 | $0 | +$0 |
What this measures
A focused comparison—not a full homeownership forecast.
For the selected down payment, the tool invests the unused cash immediately and compares its 30-year projected value with the future value of the additional P&I and modeled PMI created by putting less down. A positive number favors the investing path under these assumptions.
It does not include property taxes, homeowners insurance, HOA dues, closing costs, maintenance, home-price appreciation, investment taxes, mortgage-interest deductions, changing rates, lender-specific PMI rules, or market volatility.