As someone who sold 40 year loans before the GFC, a 50 year loan is fucking stupid....
You save around $142/mo on a median home ($400,000). Here's the best part....
You spent 2x the amount on interest over the life of the loan.
You're able to buy a 5% more expensive home (fucking stupid)
Here's the math
30-year term (360 months) @ 6.17%
Monthly interest rate = 6.17% / 12 ≈ 0.0051417.
Monthly payment ≈ $2,442.09.
(Calculation: rate/(1−(1 rate)^−360) × $400,000)
Total paid over 30 years = ~$2,442.09 × 360 ≈ $879,152 (principal interest).
Total interest ≈ $879,152 − $400,000 = $479,152.
50-year term (600 months) @ 6.67%
Monthly interest rate = 6.67% / 12 ≈ 0.0055583.
Monthly payment ≈ $2,306.23.
(Calculation: rate/(1−(1 rate)^−600) × $400,000)
Total paid over 50 years = ~$2,306.23 × 600 ≈ $1,383,738.
Total interest ≈ $1,383,738 − $400,000 = $983,738.