Mortgage Term Simulator: 15 vs 30 vs 40 vs 50 Years
Compare monthly payments, lifetime cost, payoff age, and affordability across traditional and emerging ultra-long mortgages.
📈Equity growth & payoff age
⚖️Lifetime cost meter
💡Pros & cons explained
Loan & borrower inputs
Start here
Example: 450000 = $450k financed.
We still calculate all four terms — the active one drives charts & headline metrics.
$90,000/yr
Assumes up to ~30% of gross income can go toward mortgage payments (can be adjusted in code).
Refinance scenario builder
Optional what-if
Scenario: Start with your selected term → refinance after X years into a shorter term & (optionally) lower rate.
Refi outcome vs stay-the-course
Toggle the switch to simulate a refinance.
Headline metrics (active term)
30-year focus
Monthly payment
$0
Principal & interest only.
Total interest
$0
Cost of borrowing over full term.
Lifetime cost
$0
Principal + interest paid.
Age at payoff
–
Based on your current age.
Equity growth over time
Year-by-year principal paid.
Lifetime cost meter
Total paid (principal + interest) by term.
Term comparison: payment, cost & payoff age
All four terms
Term
Monthly
Total Interest
Total Cost
Payoff Age*
*Payoff age uses your current age input. Longer terms can push payoff into retirement years.
Affordability index by term
Income slider powered
Using your income and a 30% payment-to-income rule of thumb, here’s how much loan each term could support if you maxed out that budget.
Term
Max Monthly Budget
Max Loan Estimate
Relative Affordability
Pros, cons & tradeoffs (especially for 40 & 50-year ideas)
Educational layer
Potential upsides
Lower monthly payments make higher-priced homes or expensive markets more reachable.
Cash-flow flexibility: frees up money for retirement, investing, or debt payoff instead of principal.
Smoother qualification when underwriter focuses on the lower payment rather than total cost.
Bridge strategy: some borrowers plan to refinance or sell long before 40–50 years.
Key downsides
Slower equity build: early years are mostly interest, especially on ultra-long terms.
Much higher lifetime interest — the "lifetime cost" bar makes this visible instantly.
Age-at-payoff risk: 40–50 year terms can push payoff well into retirement age.
Sensitivity to rate changes: small increases in rate have big effects over long horizons.
Use the charts as a gut-check: green favors short-term affordability; red highlights long-term cost and late payoff ages. Ultra-long mortgages may appear in headlines during affordability crises, but the tradeoff is almost always more interest for more time.