Payment Shock Calculator.

Three scenarios that quietly redraw a household budget.

Most homeowners haven't recalibrated their housing payment since closing. Three things drift over time — rates, taxes, insurance — and any one of them moving substantially can add hundreds of dollars to the monthly bill. The Payment Shock tool surfaces what each looks like, separately and combined.

Scenario 1: ARM reset

If you took a 5/1, 7/1, or 10/1 ARM, your rate is fixed for the introductory period and then adjusts annually thereafter. The first reset can move the rate by 2 percentage points, sometimes more, depending on the index, margin, and rate caps in your loan. On a $400K balance, a 2-point rate jump can add $400–$500 to monthly P&I overnight. ARM holders should run this calculator at least annually as the reset approaches.

Scenario 2: insurance and tax creep

Homeowners insurance has risen 30% to 80% in many U.S. markets over the past three years — Florida, Texas hail country, California wildfire zones, and most coastal markets are seeing major year-over-year increases. Property tax assessments, particularly post-purchase reassessments and millage-rate increases, can add another 10–25% over a 3-year window. Combined, the non-PI portion of a payment can rise 30%+ without anyone noticing month to month, just escrow shortfalls at year-end.

Scenario 3: refinance to a higher rate

If you took a 2020-era loan at 3% and you're considering a refi (cash-out, divorce-related restructuring, anything else that requires re-underwriting), you'll likely refinance at today's rate. On a $300K balance, moving from 3% to 7% adds about $750 to monthly P&I — a real shock.

What to do with the result

• If the shocked payment is under 110% of current, you have meaningful margin. Most stress events are absorbable.
• 110–125%, the household will feel it. Worth confirming reserves can cover the gap for at least 6 months while you adjust other spending.
• 125%+, the shock would force real changes. Build reserves, pay down non-housing debt, or start considering whether the home is the right fit for the medium term.