A handful of ratios summarize almost everything about your financial position: how your housing payment breaks down, how much of your income is spoken for, and how much of your home you actually own. Lenders lean on these same numbers, so understanding them means understanding how your file reads from the other side of the desk.
P&I vs. Escrow
A typical mortgage payment has two very different parts. Principal and interest (P&I) is the part that services the loan itself — interest to the lender, principal against your balance. Escrow is money the lender collects monthly and holds to pay your property taxes and homeowners insurance when those bills come due.
The distinction matters because only P&I is affected by refinancing, recasting, or extra payments. If taxes and insurance make up a big slice of your payment, even a great refinance will move the total less than you might hope — and rising taxes can push your payment up with no change to the loan at all.
Debt-to-Income Ratio (DTI)
DTI is your total monthly debt payments divided by your gross (pre-tax) monthly income. If your mortgage, car loan, and card minimums total $2,500 and you gross $7,000 a month, your DTI is about 36%.
Lenders read DTI as capacity: how much room your income has for another payment. Lower is stronger, and most loan programs have internal ceilings — though where those lines sit varies by program, lender, and the rest of your file, so no single number guarantees an approval or a denial. For your own planning, a rising DTI is an early warning that obligations are outgrowing income.
Residual Income
Where DTI is a percentage, residual income is a dollar figure: your income minus all monthly obligations — debt payments, taxes, insurance, and basic living costs. It answers the plainer question: after everything is paid, how many actual dollars are left?
Residual income catches what DTI misses. Two households can share the same 40% DTI, but the one earning three times as much has far more absolute cushion. Some loan programs (VA loans, notably) evaluate residual income directly for exactly this reason. For budgeting, it is arguably the most honest single number you have.
Total Expense Ratio
The total expense ratio widens the lens further: all monthly obligations — housing, debts, insurance, and other recurring commitments — divided by income. It is the share of every paycheck that is already claimed before you make a single discretionary choice.
A high total expense ratio means fragility: little slack for a surprise bill, a rate adjustment, or an income dip. Watching this ratio trend over time tells you whether your finances are loosening or tightening.
Loan-to-Value (LTV)
LTV shifts from income to assets: total loan balances secured by a property, divided by the property's current market value. Owe $240,000 on a home worth $400,000 and your LTV is 60% — meaning 40% of the value is your equity.
Lenders read LTV as collateral risk. Lower LTV generally means better pricing, more available options, and — below certain common thresholds — no mortgage insurance requirement. LTV is also the gatekeeper for tapping equity, since underwriting caps typically limit how high your combined LTV can go after a cash-out refinance or home equity loan.
Seeing Your Own Ratios
These five numbers together form a compact snapshot: payment composition, income capacity, dollar cushion, total burden, and equity position. The free Shouldirefi Financial Audit at /tool/audit calculates all of them from your own figures, and the free Analysis Tool shows how a refinance or payoff strategy would shift them — all as estimates you can sanity-check against your real statements.
All figures are estimates for informational purposes only — not financial advice. Consult a qualified professional before making financial decisions.