Glossary & Definitions
Master the math behind your life. Browse our comprehensive dictionary of financial, health, and business terms to understand the formulas powering our calculators.
Finance
Understand the core concepts of banking, mortgages, and investments.
Annual Percentage Rate (APR)
APR (Annual Percentage Rate) measures the total yearly cost of a loan. Unlike a simple interest rate, APR includes lender fees, giving you the true cost of borrowing.
Annual Percentage Yield (APY)
APY (Annual Percentage Yield) is the real rate of return earned on an investment in a year, accounting for the effect of compounding interest.
Amortization
Amortization is an accounting technique used to periodically lower the book value of a loan or intangible asset over a set period of time.
Compound Interest
Compound interest occurs when you earn interest on both your original deposit and on the interest that has already accumulated over time.
Debt-to-Income Ratio (DTI)
The percentage of your gross monthly income that goes toward paying your monthly debt payments.
Safe Withdrawal Rate
The estimated percentage of savings you can withdraw each year during retirement without running out of money.
Compound Frequency
How often interest is added to the principal balance of a loan or investment.
Purchasing Power
The value of a currency expressed in terms of the amount of goods or services that one unit of money can buy.
Future Value (FV)
The value of a current asset at a specific date in the future based on an assumed rate of growth.
Present Value (PV)
The current value of a future sum of money or stream of cash flows given a specified rate of return.
Inflation Rate
The percentage at which the price of goods and services is rising, which directly reduces your purchasing power.
Fixed Payment
An installment payment that remains the same for the entire term of the loan.
Nest Egg
A substantial sum of money that has been saved or invested for a specific purpose, usually retirement.
Ordinary Annuity
A series of equal payments made at the end of consecutive periods over a fixed length of time.
Nominal Return
The amount of money generated by an investment before factoring in expenses such as taxes, investment fees, and inflation.
Health
Learn the science and metrics behind metabolism, body composition, and nutrition.
Body Mass Index (BMI)
Body Mass Index (BMI) uses your height and weight to estimate body fat and screen for potential health risks.
Basal Metabolic Rate (BMR)
The number of calories your body burns at rest just to perform basic life-sustaining functions.
Total Daily Energy Expenditure (TDEE)
Total Daily Energy Expenditure (TDEE) estimates how many calories you burn daily, including exercise and activity.
Calorie Deficit
A calorie deficit occurs when you eat fewer calories than your body burns, which forces it to use stored fat for energy.
Macronutrients (Macros)
The three primary categories of nutrients you consume in large amounts that provide your body with energy: proteins, carbohydrates, and fats.
Business
Master the fundamental ratios and equations for running a profitable business.
Profit Margin
A financial ratio showing the percentage of sales that has turned into profits after costs.
Markup
The amount added to the cost price of goods to cover overhead and create a profit.
Invoice
A time-stamped commercial document that itemizes and records a transaction between a buyer and a seller.
Sales Tax
Sales tax is a fee paid to a governing body for the sales of certain goods and services, added to the final purchase price by the retailer.
Hourly Rate
The amount of money charged, paid, or earned for every hour worked.
General
Brush up on universal mathematical concepts, conversions, and relationships.
Percentage
A number or ratio expressed as a fraction of 100.
Average (Mean)
A single number taken as representative of a list of numbers, calculated by dividing the sum of the values by the number of values.
Ratio
A mathematical relationship comparing the quantities of two different things.
Conversion
The process of changing a value or expression from one form, unit, or system to another without changing its size or amount.
Duration
The measurable length of time that something continues or exists between a start and end point.
Inseam
The measurement of the inner leg from the crotch down to the ankle or hem.
Outseam
The measurement along the outside of the leg from the waist down to the hem.
Bust Measurement
The circumference around the fullest part of the chest, used primarily in women's apparel sizing.
Sleeve Length
The distance from the center back of the neck or the shoulder seam down to the wrist.
Drop Length (Suiting)
The difference in inches between a suit jacket's chest size and the waist size of its matching pants.