Amortization · Scenario Studio

Your mortgage, and the what if.

Set your loan on the left. The terracotta scenario layers on extra payments, a mid-loan refinance, or both — so you can see exactly how much interest and time it buys back.

The Loan

$
%
yrs
What if…
$
$
$
Refinance
Baseline
$2,844
monthly principal & interest
Total interest$573,950
Total paid$1,023,950
Paid offSep 2056
What If
$3,144
monthly incl. extra
Total interest$418,777
Total paid$868,777
Paid offOct 2049
You'd pay off Oct 2049 instead of Sep 2056, saving $155,173 overall.
$3,202
Saved by yr 5
$155,173
Interest saved
6y 11mo
Sooner payoff

Prepay vs. invest the extra

Investing your $300/mo instead of prepaying. Prepaying saves a guaranteed $3,202 by yr 5 (tax-free). Here's what the market nets after tax across three return cases:

Conservative%
$2,042
after-tax gain
Portfolio$20,402
Pre-tax gain$2,402
Tax paid$360
vs prepay−$1,161
Central%
$2,956
after-tax gain
Portfolio$21,478
Pre-tax gain$3,478
Tax paid$522
vs prepay−$246
Optimistic%
$4,446
after-tax gain
Portfolio$23,231
Pre-tax gain$5,231
Tax paid$785
vs prepay+$1,244
It's a split. After 15% cap-gains tax, investing wins in the higher-return case but prepaying's guaranteed $3,202 wins at the low end. The crossover sits right around your 6.50% mortgage rate — which is exactly why this is a real decision, not an obvious one.

Balance over time

Baseline What if
$0k$100k$200k$300k$400k$500k20262029203220352038204120442047205020532056

Schedule

YearPaymentPrincipalInterestExtraBalance
Yr 1 · 2026 – 2027$37,732$8,739$28,993$3,600$441,261
Yr 2 · 2027 – 2028$37,732$9,324$28,407$3,600$431,937
Yr 3 · 2028 – 2029$37,732$9,949$27,783$3,600$421,988
Yr 4 · 2029 – 2030$37,732$10,615$27,117$3,600$411,373
Yr 5 · 2030 – 2031$37,732$11,326$26,406$3,600$400,047
Yr 6 · 2031 – 2032$37,732$12,084$25,647$3,600$387,963
Yr 7 · 2032 – 2033$37,732$12,894$24,838$3,600$375,069
Yr 8 · 2033 – 2034$37,732$13,757$23,974$3,600$361,312
Yr 9 · 2034 – 2035$37,732$14,679$23,053$3,600$346,633
Yr 10 · 2035 – 2036$37,732$15,662$22,070$3,600$330,972
Yr 11 · 2036 – 2037$37,732$16,711$21,021$3,600$314,261
Yr 12 · 2037 – 2038$37,732$17,830$19,902$3,600$296,431
Yr 13 · 2038 – 2039$37,732$19,024$18,708$3,600$277,408
Yr 14 · 2039 – 2040$37,732$20,298$17,434$3,600$257,110
Yr 15 · 2040 – 2041$37,732$21,657$16,074$3,600$235,453
Yr 16 · 2041 – 2042$37,732$23,108$14,624$3,600$212,345
Yr 17 · 2042 – 2043$37,732$24,655$13,077$3,600$187,690
Yr 18 · 2043 – 2044$37,732$26,306$11,425$3,600$161,384
Yr 19 · 2044 – 2045$37,732$28,068$9,664$3,600$133,315
Yr 20 · 2045 – 2046$37,732$29,948$7,784$3,600$103,367
Yr 21 · 2046 – 2047$37,732$31,954$5,778$3,600$71,414
Yr 22 · 2047 – 2048$37,732$34,094$3,638$3,600$37,320
Yr 23 · 2048 – 2049$37,732$36,377$1,355$3,600$943
Yr 24 · 2049 – 2049$949$943$5$300$0