Calculating your total debt starts with listing every dollar you owe, then organizing those balances to understand your full financial picture. Whether you need the number for a loan application, a budgeting exercise, or just peace of mind, the process is straightforward once you know what counts as debt and what doesn’t.
What Counts as Debt
Debt is any money you owe to someone else, whether that’s a bank, a government agency, a store, or your brother-in-law. The Consumer Financial Protection Bureau draws a useful line: a regular monthly bill like your phone plan isn’t debt, but a past-due amount on that bill is. If you’re repaying a loan of any kind, the entire remaining balance qualifies as debt.
Here’s a checklist of the most common types to include:
- Mortgage: Your remaining home loan balance, including any home equity loans or lines of credit.
- Auto loans: The payoff balance on any vehicle you’re financing.
- Student loans: Federal and private, even if they’re in deferment or forbearance.
- Credit cards: The full statement balance on every card, not just the minimum payment.
- Medical debt: Any outstanding balances with hospitals, clinics, or collection agencies.
- Personal loans: Including money borrowed from friends or family.
- Payday loans: The principal plus any fees still owed.
- Past-due obligations: Back child support, overdue rent, unpaid property taxes, back income taxes, or outstanding court fines and fees.
- Buy now, pay later plans: These work like installment loans. If you split a $400 purchase into four payments and still owe $300, that $300 is debt.
Buy now, pay later balances are easy to overlook because the payments feel small and often come out of your account automatically. But they add up, especially if you have several running at once. Treat each remaining balance as a line item in your debt total.
Step-by-Step: Adding Up Your Total Debt
Gather your most recent statements for every account listed above. For credit cards and revolving lines of credit, use the current balance (not the credit limit). For installment loans like mortgages and auto loans, use the payoff balance, which your lender can provide or which often appears on your online account dashboard. For informal debts like money owed to family, write down the amount you’ve agreed to repay.
Create a simple list or spreadsheet with four columns: the creditor’s name, the type of debt, the total balance owed, and the monthly payment. Once every account is filled in, sum the balance column. That’s your total debt. Sum the monthly payment column separately, because you’ll need that number for the next calculation.
If you’re unsure whether you’ve captured everything, pull your credit reports from annualcreditreport.com. Your reports won’t show debts to friends or family, but they will surface forgotten store cards, old medical collections, or loans you may have lost track of.
How to Calculate Your Debt-to-Income Ratio
Your debt-to-income ratio (DTI) is the single most common way lenders judge whether you can handle more debt. It compares your total monthly debt payments to your gross monthly income (your pay before taxes and deductions).
The formula is simple:
DTI = Total Monthly Debt Payments ÷ Gross Monthly Income × 100
Say you pay $1,400 for your mortgage, $350 for a car loan, $200 toward student loans, and $150 in credit card minimums. That’s $2,100 in monthly debt payments. If your gross monthly income is $6,000, your DTI is $2,100 ÷ $6,000 = 0.35, or 35%.
Fannie Mae, which sets the rules for most conventional mortgages, generally caps DTI at 36% for manually underwritten loans, though borrowers with strong credit scores and cash reserves can qualify with a DTI up to 45%. Loans run through Fannie Mae’s automated system may be approved with a DTI as high as 50%. As a practical benchmark, keeping your DTI below 36% gives you the most borrowing flexibility and signals to any lender that your debt load is manageable.
Calculating How Much Interest You’re Paying
Knowing your total balances is only part of the picture. Understanding how much those balances cost you each month helps you prioritize which debts to tackle first.
For fixed-rate installment loans like mortgages and auto loans, your monthly statement already breaks out how much of each payment goes to interest versus principal. Early in the loan, most of the payment is interest; that share shrinks over time.
Credit cards work differently. Most card issuers calculate interest daily using your average daily balance. They take your annual percentage rate (APR), divide it by 365 to get the daily periodic rate, then multiply that rate by your balance each day. Those daily charges accumulate throughout the billing cycle. This means carrying a $5,000 balance on a card with a 22% APR costs you roughly $3 per day in interest, or about $90 per month, even if you’re making minimum payments. The sooner you pay down any portion of the balance, the less interest accrues the next day.
To estimate monthly interest on any single debt, use this shortcut: multiply the balance by the annual interest rate, then divide by 12. A $15,000 student loan at 6% costs roughly $75 per month in interest ($15,000 × 0.06 ÷ 12). This gives you a quick way to see which debts are costing you the most.
Calculating Business Debt Capacity
If you’re calculating debt for a business rather than personal finances, lenders use a metric called the debt service coverage ratio (DSCR). It measures whether your business earns enough to cover its debt payments.
DSCR = Net Operating Income ÷ Total Debt Service
Net operating income is your revenue minus operating expenses (payroll, rent, supplies, and similar costs, but not debt payments themselves). Total debt service is the sum of all principal and interest payments due over the period you’re measuring, typically one year.
A DSCR of 1.0 means your business earns exactly enough to cover its debt payments with nothing left over. Below 1.0 means you’re falling short. Most lenders want to see a DSCR of at least 1.2 to 1.25 before approving a loan, and a ratio of 2.0 or higher is considered very strong because it means the business generates twice what it needs to service its debt.
To calculate yours, pull your annual income statement, subtract operating expenses from revenue, then divide by the total of all loan and lease payments due over the same period. If your DSCR falls below 1.25, lenders will likely either deny additional borrowing or charge higher interest rates to compensate for the risk.
Putting the Numbers to Work
Once you have your total debt, your DTI, and a sense of what each debt costs in interest, you can make informed decisions. If your DTI is above 36%, focus on paying down the balances with the highest interest rates first, since those are draining the most money each month. If you’re preparing for a mortgage application, know that reducing your DTI even a few percentage points can change what you qualify for.
Revisit your debt calculation every few months. Balances change, new obligations appear (especially small ones like buy now, pay later plans), and old debts get paid off. Keeping an updated number takes ten minutes and prevents the kind of slow creep that turns manageable debt into a problem.