Reference

Glossary

Plain-English definitions of the construction, finance, health, and math terms behind our calculators and guides.

4 A B C D E F H J L M O P Q R S T U V W

4

401(k) match: An employer contribution that matches part of what an employee puts into their 401(k), such as 50 cents per dollar up to 6 percent of pay. It is effectively free retirement money.

A

APR: Annual Percentage Rate — the yearly cost of borrowing expressed as a percentage, including interest and certain fees. Unlike APY, it does not account for compounding.
APY: Annual Percentage Yield — the real rate of return on savings or investments in one year, accounting for compound interest. APY is always equal to or higher than the stated interest rate.
Activity factor: A multiplier applied to Basal Metabolic Rate to estimate total daily calorie needs based on exercise level. It ranges from about 1.2 for sedentary people to 1.9 for very active people.
Adjusted gross income: Adjusted Gross Income (AGI) is your total gross income minus specific adjustments like retirement contributions and student loan interest. It determines eligibility for many deductions and credits.
Amortization: The process of paying off a loan through fixed periodic payments that cover both interest and principal. Early payments go mostly to interest, while later payments reduce principal faster.
Asphalt shingle: The most common roofing material in the U.S., made from a fiberglass mat coated with asphalt and mineral granules. A standard three-tab shingle roof lasts 15 to 30 years.

B

BMI: Body Mass Index — a measure of body fat based on weight and height, calculated as weight in kilograms divided by height in meters squared (kg/m squared). It screens for underweight, normal, overweight, and obese ranges.
BMI category thresholds: The standard ranges that classify Body Mass Index: below 18.5 is underweight, 18.5 to 24.9 is normal, 25 to 29.9 is overweight, and 30 or above is obese.
BMR: Basal Metabolic Rate — the calories your body burns at complete rest to keep you alive.
Board foot: A unit of lumber volume equal to 144 cubic inches, or a board measuring 1 foot by 1 foot by 1 inch thick. Hardwood and rough lumber are commonly priced per board foot.
Body fat percentage: The proportion of your total body weight that is fat tissue, expressed as a percentage. Healthy ranges are roughly 10 to 20 percent for men and 18 to 28 percent for women.

C

Calorie deficit: Consuming fewer calories than your body burns in a day, which forces it to use stored fat for energy. A deficit of about 3,500 calories equals roughly one pound of fat loss.
Calorie surplus: Consuming more calories than your body burns in a day, the energy state required to gain weight or build muscle. A surplus of about 3,500 calories equals roughly one pound gained.
Capital gains tax: A tax on the profit from selling an asset like stocks or real estate. Long-term gains on assets held over a year are taxed at preferential rates of 0, 15, or 20 percent, while short-term gains are taxed as ordinary income.
Compound interest: Interest earned on both your principal and previously earned interest, which drives long-term investment growth.
Cubic yard: A volume of 27 cubic feet — the standard unit concrete and bulk landscape materials are sold by.

D

Debt avalanche: A debt-payoff strategy that targets the balance with the highest interest rate first while paying minimums on the rest. It minimizes total interest paid compared to the snowball method.
Debt snowball: A debt-payoff strategy that pays off the smallest balance first to build momentum, then rolls that payment into the next debt. It favors psychological wins over interest savings.
Depreciation: An accounting method that spreads the cost of a tangible asset over its useful life. It lets businesses deduct a portion of an asset's value each year rather than all at once.
Discount: A reduction from the original price, usually expressed as a percentage. The sale price equals the original price multiplied by one minus the discount rate.
Downspout: A vertical pipe that carries rainwater from a gutter down to the ground or drainage system. A typical home needs one downspout for every 30 to 40 linear feet of gutter.
Drywall sheet: A standard panel of gypsum wallboard used for interior walls and ceilings, measuring 4 by 8 feet for 32 square feet of coverage. It is also called gypsum board or Sheetrock.

E

Effective tax rate: Your total tax divided by your total income; always lower than your marginal rate under progressive brackets.
Estimated quarterly taxes: Tax payments the self-employed and others without withholding must make four times a year to the IRS. They cover income tax and self-employment tax on earnings not subject to paycheck withholding.

F

FICA: The Federal Insurance Contributions Act payroll tax that funds Social Security and Medicare. Employees and employers each pay 7.65 percent, for a combined 15.3 percent on wages.
Fascia: The horizontal board running along the lower edge of a roof, behind the gutter, that caps the ends of the rafters. It supports the gutter and closes off the roof edge.
Fence post spacing: The distance between fence posts, typically 6 to 8 feet on center for wood and vinyl fences. Proper spacing keeps the fence rigid and panels properly supported.
Fiber cement siding: A durable exterior cladding made from cement, sand, and cellulose fibers, sold under brands like HardiePlank. It resists rot, fire, and insects and lasts 30 to 50 years.
Flashing: Thin metal sheeting installed at roof joints, valleys, chimneys, and walls to direct water away from vulnerable seams. It prevents leaks where surfaces meet.
Footing: A concrete base poured below the frost line to spread a structure's load onto the soil and prevent settling. Footings support foundations, posts, and columns.

H

HSA: A Health Savings Account is a tax-advantaged account for medical expenses available to those with a high-deductible health plan. Contributions are tax-deductible, growth is tax-free, and qualified withdrawals are untaxed.

J

Joist: A horizontal structural member that supports a floor or ceiling, typically spaced 16-inch on center. Joists span between walls or beams to carry the load above.

L

Lean body mass: The weight of everything in your body except fat, including muscle, bone, organs, and water. It is calculated by subtracting fat mass from total body weight.
Linear foot: A measurement of length equal to 12 inches, measured in a straight line regardless of width or thickness. Materials like gutters, trim, and lumber are often priced per linear foot.

M

Macronutrient: One of the three nutrients the body needs in large amounts for energy: protein, carbohydrates, and fat. Protein and carbs provide 4 calories per gram, while fat provides 9.
Marginal tax rate: The tax rate applied to your next dollar of taxable income — the bracket your last dollar falls into.
Markup: The amount added to a product's cost to set its selling price, expressed as a percentage of cost. A $40 item with a 50 percent markup sells for $60.
Mean: The arithmetic average of a set of numbers, found by adding all values and dividing by how many there are. It can be skewed by extreme outliers.
Median: The middle value in a sorted list of numbers, where half the values fall above and half below. It resists distortion from outliers better than the mean.
Mifflin-St Jeor equation: The most accurate formula for estimating Basal Metabolic Rate from weight, height, age, and sex. For men it is 10 times weight in kg plus 6.25 times height in cm minus 5 times age plus 5.
Mil thickness: A unit equal to one-thousandth of an inch (0.001 inch) used to measure the thickness of materials like vinyl, paint, and plastic sheeting. A higher mil count means a thicker, more durable product.

O

On-center spacing: The distance between the centers of adjacent structural members like studs or joists, commonly 16-inch on center. It standardizes framing and material layout.

P

PMI: Private Mortgage Insurance — a fee lenders charge borrowers who put down less than 20 percent on a home. It protects the lender and is typically removed once equity reaches 20 percent.
Percentage: A number expressed as a fraction of 100, written with the percent sign. To find a percentage of a value, multiply the value by the percentage and divide by 100.
Percentage change: The relative difference between an old and new value, calculated as the difference divided by the original value, times 100. A rise from 50 to 75 is a 50 percent increase.
Percentage points: The arithmetic difference between two percentages, distinct from percent change. A rise from 10 percent to 15 percent is 5 percentage points but a 50 percent increase.
Pitch multiplier: A factor that converts a roof's flat footprint area into its true sloped area based on steepness (e.g. ~1.05 for a 4/12 pitch).
Principal: The original amount of money borrowed or invested, before interest is added. Loan payments reduce the principal over time, lowering the balance on which interest accrues.
Proportion: An equation stating that two ratios are equal, such as 2 to 4 equals 3 to 6. Proportions are solved by cross-multiplying to find an unknown value.

Q

QBI deduction: The Qualified Business Income deduction lets eligible pass-through business owners deduct up to 20 percent of their qualified business income. It reduces taxable income for sole proprietors, partnerships, and S corporations.

R

Ratio: A comparison of two quantities showing how many times one contains the other, written as a to b or a:b. Ratios scale recipes, mixtures, and proportions.
Refinance break-even: The point at which the monthly savings from refinancing a loan equal the closing costs paid to refinance. It is found by dividing total closing costs by the monthly payment savings.
Roofing square: A unit of roof area equal to 100 square feet. Roofing materials and labor are priced per square.
Roth vs traditional: Two retirement account types differing in tax timing: Roth contributions are made with after-tax dollars and grow tax-free, while traditional contributions are pre-tax and taxed on withdrawal.
Rounding: Adjusting a number to a nearby simpler value at a given place. The standard rule rounds digits of 5 or more up and digits below 5 down.

S

Self-employment tax: The 15.3% Social Security and Medicare tax that the self-employed pay on net profit, covering both the employee and employer halves.
Simple interest: Interest calculated only on the original principal, not on accumulated interest. It equals principal times rate times time, growing linearly rather than compounding.
Soffit: The exposed underside of a roof overhang that bridges the gap between the wall and the fascia. Soffits are usually vented to allow airflow into the attic.
Square footage: The area of a surface measured in square feet, calculated by multiplying length by width. It is the basis for estimating flooring, paint, roofing, and siding quantities.
Standard deduction: A fixed amount that reduces your taxable income without itemizing, set for 2026 at $16,100 for single filers and $32,200 for married couples filing jointly. Most taxpayers take it instead of itemizing.
Standing-seam metal roof: A metal roofing system with raised vertical seams that interlock to hide fasteners and shed water. It is a premium option lasting 40 to 70 years.
Stud: A vertical framing member in a wall, usually a 2x4 or 2x6, spaced 16-inch on center. Studs form the skeleton that supports drywall, sheathing, and the structure above.

T

TDEE: Total Daily Energy Expenditure — the calories you burn in a day, calculated as your BMR times an activity factor.
Tax withholding: The portion of an employee's paycheck an employer sends directly to the IRS to prepay income tax. The amount is set by the W-4 form and reconciled when you file your return.
Taxable income: The portion of your income subject to tax after subtracting deductions from your adjusted gross income. It is the figure to which tax brackets are applied to calculate what you owe.
Tip: A gratuity added to a bill for service, typically 15 to 20 percent of the pre-tax total in the U.S. The tip amount equals the bill multiplied by the tip percentage.

U

Underlayment: A water-resistant barrier installed between the roof deck and the shingles to protect against leaks. Common types include felt paper and synthetic underlayment.

V

Vinyl siding: A lightweight plastic exterior cladding made from PVC, valued for low cost and minimal maintenance. It is one of the least expensive siding options, lasting 20 to 40 years.

W

Waist-to-height ratio: A measure of body fat distribution found by dividing waist circumference by height. A ratio below 0.5 is generally considered healthy for most adults.
Waste factor: An extra percentage of material added to an estimate to cover cuts, breakage, and mistakes, typically 10 to 15 percent. It ensures you order enough material to finish the job.