Debt
Extra mortgage payment
Also known as: principal prepayment.
An extra mortgage payment is money applied to a loan ahead of schedule to reduce the outstanding principal early, choosing between shortening the term or lowering the instalment.
Shortening the term maximizes interest savings; lowering the instalment improves monthly cash flow and reduces risk if income is unstable.
The savings equal a guaranteed return equal to the loan's rate, which matters most when that rate exceeds what you'd expect from a conservative investment.