Each 1% of rate ≈ 10% of buying power

A one-point rise in mortgage rates cuts what you can borrow for the same payment by roughly 10%.

Why it works

The amortization formula is steepest right where typical rates sit. From 6% to 7% on a 30-year loan, the same payment services ~11% less principal.

Do it exactly

Estimate with the rule, then check it against the calculator that models it properly.

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