DTI (Debt-to-Income Ratio)
The share of gross monthly income that goes to housing costs plus other debts — the primary limit lenders and co-op boards use to cap how much you can borrow.
Last updated: August 12, 2026DTI is the ratio of your monthly housing payment (plus any other recurring debts — car loans, student loans, credit cards) to your gross monthly income. It’s the main lever that caps how much you can borrow, and NYC’s two ownership structures apply very different limits: co-op boards are conservative, typically capping DTI around 28%, while condo lenders commonly reference the 43% figure traditionally associated with “qualified mortgage” underwriting (the CFPB’s rule has since shifted to price-based thresholds rather than a flat percentage, but 43% remains the number most lenders and calculators still use as a practical ceiling).
Formula: DTI = (Monthly mortgage/maintenance + other monthly debts) ÷ Gross monthly income
Worked example
A buyer earning $150,000/year ($12,500/month gross) with a co-op board’s 28% DTI limit has a total housing-plus-debt budget of $12,500 × 0.28 = $3,500/month. If they carry $300/month in other debt, only $3,200/month is left for mortgage + maintenance combined — which is what actually caps their max purchase price. See co-op vs condo costs for how the tighter co-op DTI limit compares to condo lending, or run your own numbers on the Co-op or Condo calculator.