Extra mortgage vs investing

Guaranteed coupon vs expected return on the extra dollars. Type the rate on your payoff letter — default 7% is the extra-principal file, not today’s lock. Freddie Mac PMMS printed 6.71% the week of September 3, 2026; that is an average of applications. Primer: refi vs extra principal. Sequence: 12-step playbook. Do not rebuild the HELOC vs cash-out tap here.

The loan

Remaining balance ($) Coupon % (your payoff letter, not PMMS) Years left Extra principal / month ($) Monthly PMI still drafting ($) Original value for 80% PMI drop ($)

The other pile

Expected invest return % (example, not a forecast) Horizon (years) Federal marginal % Share of interest you actually itemize %

0 = 2026 standard deduction ($16,100 single / $32,200 MFJ, Rev. Proc. 2025-32). 100 = you itemize every dollar of qualified residence interest. After-tax coupon ≈ rate × (1 − federal × this fraction).

Extra vs invest

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Educational estimate. Extra equity at the horizon is remaining balance without extra minus remaining with extra — house appreciation hits both. Investing is expected, volatile, and wrapper-dependent. PMI drop is 80% of the original value you typed (Homeowners Protection Act request; automatic is typically 78% if current). Do not cash-out a cheap first lien to “invest the spread” — that file is HELOC vs cash-out. Paid sequence: extra vs investing playbook. Break-even months: refi guide.