Mortgage Stress Test
Run a mortgage stress test. See your payment at current rate +1%, +2%, +3% — and find the rate at which housing debt exceeds 38% of gross income.
Mortgage Stress Test
Enter your current mortgage and income details. The test shows what your monthly payment becomes if rates rise 1%, 2%, or 3% — and the break-point rate at which total housing debt exceeds your affordability threshold.
| Scenario | Rate | Monthly | Total DTI | Verdict |
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How to Use the Mortgage Stress Test
Enter your current mortgage
Balance, current rate, and years remaining come from your most recent mortgage statement. For ARM loans, use the current rate — not the start rate from when you took the loan.
Add household income and other debt
Gross monthly income before taxes — both spouses if you bought jointly. "Other debt" is the sum of monthly minimum payments on auto loans, student loans, credit cards, and any other consumer debt that lenders include in your DTI calculation.
Set your affordability ceiling
US mortgage lenders use 36-43% back-end DTI as the cutoff for qualifying borrowers (CFPB ATR/QM rule). 38% is a common conservative target — leaves room for emergencies. Canada's OSFI B-20 uses ~39% for similar reasons. Set your own personal ceiling here.
Read the scenarios and the break-point
The table shows your monthly payment at +0%, +1%, +2%, +3%. Rows highlighted red exceed your threshold. The break-point card below shows the exact rate at which total housing debt crosses your ceiling — useful if you have an ARM coming up for reset.
Mortgage Stress Testing — Why Lenders Already Do This, and Why You Should Too
The Regulatory Background
After the 2008 mortgage crisis, US regulators codified the Ability-to-Repay (ATR) rule — 12 CFR 1026.43 — which requires lenders to make a good-faith determination that a borrower can repay the loan, including under reasonably foreseeable rate scenarios for adjustable-rate mortgages. The Qualified Mortgage (QM) standard layered on top sets a 43% back-end debt-to-income ceiling above which loans lose their "safe harbor" status. Canada's Office of the Superintendent of Financial Institutions (OSFI) went further with Guideline B-20, which since 2018 has required uninsured Canadian mortgages to qualify at the greater of (a) the contract rate plus 2 percentage points, or (b) the published 5-year fixed rate — the federal stress test that has shaped Canadian housing affordability ever since.
The personal version of this exercise is exactly what the tool above runs: take your current mortgage, add scenarios at +1pp, +2pp, +3pp, and see whether the resulting monthly payment plus your other debt obligations breaches your personal affordability ceiling. For US borrowers with adjustable-rate mortgages (5/1, 7/1, 10/1 ARMs), this is the single most important question to ask each year — and especially in the 12 months before the first rate reset.
Back-End DTI: The Single Number That Decides Your Mortgage
The back-end debt-to-income ratio (DTI) is the percentage of your gross monthly income that goes to all monthly debt obligations — mortgage principal and interest, property taxes, homeowners insurance, HOA fees, plus auto loans, credit card minimums, student loans, and any installment debt. Lenders prefer 36% or below; the CFPB's QM standard caps it at 43%; non-QM lenders may go to 50% in special cases. The tool above uses back-end DTI as the threshold because it's the actual gatekeeper number — front-end (housing only) DTI is a softer constraint.
For a household earning USD 100,000 per year (USD 8,333/month gross), a 38% DTI ceiling means total monthly debt service can't exceed USD 3,167. If auto and student loans already take USD 600, your maximum monthly mortgage payment is USD 2,567. At 6.5% on a 30-year loan, that supports a USD 405,000 mortgage. At 8.0%, only USD 350,000. The 1.5pp rate movement is worth USD 55,000 of buying power.
"A 2pp rise on a USD 320,000 / 27-year mortgage adds roughly USD 410 to the monthly payment — enough to push a borrower from 35% DTI to 40% DTI on a typical US household income."
When to Run This Test on Yourself
Three triggers should make you run a personal stress test: (1) you have an ARM with a reset coming in the next 12-24 months — the stress test tells you what you're walking into; (2) you're considering refinancing into an ARM to get a lower starter rate — the test tells you the worst-case payment after reset; (3) you bought near the top of your DTI in a low-rate environment and rates have moved against you — the test tells you how much headroom you have if your income drops or your other debt rises.
The other use case is buying. Lenders qualify you at today's rate, but you'll have to live with the payment if rates rise during the life of the loan. Self-stress-testing at +2pp gives you a buffer beyond what the lender's QM minimum ensures. Conservative borrowers buy a house where the +2pp scenario still fits inside 36% DTI; aggressive borrowers max out at 43% even at today's rate and accept the risk of needing to refinance or sell if rates move further.
10 Facts About Mortgage Stress Testing
The Ability-to-Repay (ATR) rule (12 CFR 1026.43) is the federal requirement that US lenders prove a borrower can repay — including under foreseeable rate scenarios.
The Qualified Mortgage (QM) standard caps back-end DTI at 43% for loans to retain their safe-harbor status with the CFPB.
Canada's OSFI Guideline B-20 requires uninsured mortgages to qualify at the contract rate +2pp — a hard floor that has shaped Canadian housing affordability since 2018.
The Bank of England ran formal mortgage stress tests on UK lenders from 2014-2022 — testing portfolio resilience to 7% mortgage rates.
For a USD 300,000 / 30-year loan, a 1 percentage point rate rise increases monthly payment by roughly USD 180 — and lifetime interest by USD 65,000.
The 5/1 ARM (5-year fixed, then annual adjustments) is the most common US ARM — typical reset caps are 2pp per year and 5pp lifetime.
US lenders typically prefer back-end DTI ≤ 36%, will stretch to 43% for QM, and may go to 50% for non-QM borrowers with strong compensating factors.
The Federal Reserve's Beige Book publishes anecdotal economic conditions every six weeks — including consumer mortgage stress indicators by district.
EU consumer mortgage rules under Directive 2014/17/EU require lenders to assess creditworthiness using "appropriately accurate" income and expense information — softer than US ATR.
The 2008 mortgage crisis in the US was driven partly by stated-income loans where ATR was effectively absent — the rule explicitly responds to that experience.
Frequently Asked Questions
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A mortgage stress test models what your monthly payment becomes if interest rates rise. It answers the question "could I still afford my mortgage if rates were 2 percentage points higher?" Lenders run formal stress tests during underwriting under regulations like the US Ability-to-Repay rule and Canada's OSFI B-20. The personal version is the same exercise: apply scenarios of +1pp, +2pp, +3pp to your current rate, check whether the new monthly payment plus your other debt still fits inside your personal affordability threshold (typically 36-43% of gross monthly income).
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Back-end debt-to-income (DTI) is the percentage of your gross monthly income that goes to all monthly debt obligations — mortgage payment, property taxes, homeowners insurance, HOA fees, auto loans, credit card minimums, student loans, and any other recurring debt service. The CFPB's Qualified Mortgage rule caps it at 43% for safe-harbor loans. Lenders generally prefer 36% or below. It matters because it's the single most predictive number for default risk — if your DTI exceeds 43%, even a small income drop or expense spike can push you into delinquency.
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These are calibrated to typical ARM reset caps and observed historical rate moves. Most US adjustable-rate mortgages cap the annual adjustment at 2 percentage points and the lifetime adjustment at 5 percentage points. The 2007-2023 period saw 30-year fixed rates move from ~3% to ~8% — a 5-percentage-point range. Testing +1pp, +2pp, +3pp covers the realistic short-term stress for a fixed-rate borrower and the typical first-reset stress for an ARM borrower. Canada's OSFI B-20 stress rate is contract +2pp, which falls between scenarios two and three on this tool.
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Enter your current loan balance, the current note rate (the one you're paying today, not the start rate from origination), and the years remaining. The tool's +1, +2, +3 scenarios will show what monthly payment you face if you reset at +1pp / +2pp / +3pp. Your loan note specifies the reset index (typically the Secured Overnight Financing Rate or SOFR, or the older one-year Treasury), the margin (typically 2.25-2.75pp), and the periodic + lifetime caps. Compare today's index value to the index value when you signed — that delta plus the margin is approximately your new rate. If the worst case fails the affordability test, refinance into a fixed-rate product before the reset.
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This tool models principal and interest only — the PI portion of PITI. To capture the full housing payment, add your monthly property taxes (1/12 of annual), homeowners insurance, and HOA into the "Other monthly debt" field, or reduce your affordability threshold accordingly. A more conservative version: subtract estimated annual property taxes + insurance from gross income before computing DTI. For US borrowers, property taxes typically run 0.5-2.5% of home value annually depending on state — that's USD 200-1,000/month on a USD 500,000 home.
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Front-end DTI is just housing (mortgage PITI ÷ gross income); back-end DTI adds all other recurring debt. Conventional US lenders target front-end ≤ 28% and back-end ≤ 36%, with absolute ceilings of 31% / 43% on QM loans. This tool uses back-end as the threshold because it's the actual gating ratio — front-end can be met but back-end fail if other consumer debt is high.
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Canada's Office of the Superintendent of Financial Institutions Guideline B-20 requires uninsured Canadian mortgage borrowers to qualify at the greater of (a) their contract rate + 2 percentage points or (b) the Bank of Canada's qualifying rate (currently published as the 5-year fixed benchmark). Introduced January 2018, B-20 has materially shaped Canadian housing affordability — it's why a Canadian household pre-approved at 4.5% must qualify their budget as if rates were 6.5%. The US has no direct equivalent, though the QM rule's 43% DTI cap functions similarly.
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Three options: (1) reduce other debt — pay off the auto loan or credit card balances; even USD 200/month off other debt service moves the headroom; (2) extend the mortgage term — going from 27 years left to a fresh 30-year refinance lowers the monthly payment, but at the cost of much more lifetime interest; (3) increase income — refinances qualify off the higher household income if a spouse returns to work or you get a promotion. The order to try is usually 1 → 2 → 3 because debt paydown is the only one that improves your finances rather than rearranging them.
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Singapore has the strictest formal regime: the Mortgage Servicing Ratio (MSR) caps HDB mortgage payments at 30% of gross monthly income; the Total Debt Servicing Ratio (TDSR) caps total monthly debt at 55%. Both are MAS-enforced and apply to every new property loan. Malaysia uses a similar 60% DSR (Debt Service Ratio) ceiling for retail mortgages. Indonesia, Philippines, and Vietnam have less formal qualification rules but typical bank thresholds of 30-40% mortgage / gross income. Compared to US/Canada, ASEAN regimes are blunter (a single percentage cap rather than DTI scenarios) but generally more conservative. If you have an SG/MY loan, the right tool is our Mortgage Calculator with its TDSR-aware logic.
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Use 36% back-end DTI rather than the 38% default. Two reasons specific to expats: (1) your US emergency cushion is usually smaller — you don't yet have the network, family backstop, or local credit lines you'd have at home; (2) currency-flow risk if part of your income or savings is in SGD/MYR — a USD strengthening cycle can pressure your USD-denominated mortgage in ways a US-born borrower doesn't face. The 36% ceiling gives you 7-9% of pre-tax income as a buffer. Conservative ASEAN expats with single-income households should consider 32-34%.
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