A Glossary of Everyday Budgeting Terms

Gross Income

The total amount you earn before any taxes, deductions, or withholdings are taken out. This is the number on your offer letter or contract, not the amount deposited in your bank account.

Net Income

The amount of money you actually receive after taxes and deductions have been subtracted from your gross income. Net income — not gross — is what you should use as the foundation of your budget.

Fixed Expenses

Recurring costs that stay the same each month, such as rent, a mortgage payment, or a car loan. Because these don't fluctuate, they're the easiest to plan for in a budget.

Variable Expenses

Costs that change month to month, such as groceries, gas, or utility bills. Variable expenses require more active tracking because the amounts aren't predictable.

Discretionary Spending

Money spent on wants rather than needs — dining out, entertainment, subscriptions, and similar non-essential purchases. Discretionary spending is often the first area reviewed when cutting a budget.

Non-Discretionary Spending

Expenses that are considered essential and difficult to eliminate, such as housing, food, transportation, utilities, and healthcare costs. These commitments typically take priority in any budget.

Budget Deficit

The result when your total expenses exceed your total income in a given period. A recurring deficit signals that spending adjustments or income increases are needed to avoid accumulating debt.

Budget Surplus

The amount left over after all expenses are paid — essentially what remains from your net income. A surplus creates room to save, invest, or pay down debt faster.

Zero-Based Budget

A budgeting method where every dollar of income is assigned a specific purpose — saving, spending, or debt repayment — so that income minus all allocations equals zero. No dollar is left unaccounted for.

Pay Yourself First

A savings strategy where a set amount is transferred to savings or an investment account immediately when income arrives, before any other spending. This treats saving as a non-negotiable expense rather than an afterthought.

Emergency Fund

A dedicated pool of liquid savings set aside specifically for unexpected expenses or income disruption — such as a job loss, medical bill, or major repair. It is kept separate from regular spending accounts.

Debt-to-Income Ratio (DTI)

A percentage calculated by dividing your total monthly debt payments by your gross monthly income. Lenders use DTI to assess borrowing capacity, and it's a useful self-check on how much of your income is committed to debt obligations.