Money words, brought down to deck level.
This glossary explains 12 personal-finance terms in plain English, with a practical example for each. Start with cash flow and a basic budget, then use concepts such as sinking funds, utilization, and net worth when they solve a real problem. Knowing the label matters less than knowing the next action.
APR
Annual percentage rate estimates the yearly cost of borrowing, including interest and certain fees. A credit card with a 24% APR does not charge 24% each month; its periodic rate is applied to carried balances. Paying the statement balance in full usually avoids purchase interest.
APY
Annual percentage yield estimates what savings earns in one year after compounding. A 4% APY on a steady $1,000 balance produces about $40 over a year. APY makes accounts easier to compare because it includes the effect of interest earning interest.
Budget
A budget is a plan for directing expected income toward spending, saving, and debt payments. It is not a forensic report or a punishment. A useful budget changes when life changes and gives every important expense a job before the money is gone.
Cash flow
Cash flow is money entering and leaving over a period. Positive cash flow means inflows exceed outflows; negative means the reverse. Timing matters: a monthly plan can look balanced while a bill due on the 2nd still arrives before a paycheck on the 5th.
Compound interest
Compound interest is interest calculated on both the original amount and prior interest. It helps long-term savings grow and makes revolving debt costlier. Time and rate both matter: a modest rate over decades can outweigh a high rate applied for only a few months.
Credit utilization
Credit utilization is the share of available revolving credit currently reported as used. A $600 reported balance across $3,000 of limits equals 20%. Lower utilization can support a credit score, but paying on time and avoiding unnecessary interest matter more than chasing a perfect percentage.
Emergency fund
An emergency fund is cash reserved for unplanned, necessary expenses or lost income. The first useful target may be one insurance deductible or $500, not an intimidating six-month total. Keep it accessible and separate enough that ordinary spending does not quietly absorb it.
Fixed expense
A fixed expense is broadly predictable and recurs on a schedule, such as rent or an internet bill. “Fixed” does not mean permanent: insurance can renew higher and subscriptions can be canceled. The predictable timing makes these expenses the frame of a monthly plan.
Net worth
Net worth equals what you own minus what you owe. Cash, investments, and property are assets; loans and card balances are liabilities. It is a directional snapshot, not a measure of character. Tracking it quarterly can reveal progress that a single checking balance hides.
Sinking fund
A sinking fund is money saved gradually for an expected, irregular expense. Saving $100 monthly toward a $1,200 annual insurance premium turns a predictable shock into a routine line item. Unlike an emergency fund, the purpose and approximate date are known in advance.
Variable expense
A variable expense changes from period to period, such as groceries, fuel, or dining out. It is not automatically optional. Use several months of actual transactions to set a realistic range; budgeting the lowest imaginable number simply creates a plan that fails on paper.
Zero-based budget
A zero-based budget assigns every dollar of available income to spending, saving, debt, or a buffer until unassigned money equals zero. It does not mean spending the account down to zero. Goodbudget supports envelope-style planning; our review explains that workflow.
Want these terms applied rather than memorized? Start with our budgeting-app selection guide, then compare the real tools in our 2026 ranking.