Glossary

Plain definitions of the terms the calculators use, from APR and amortization to BMR, R-value and z-score, each linked to its calculator.

A

Amortization
Paying off a loan through regular payments that each cover the interest due and repay part of the principal.
Calculator: Mortgage Amortization
Annual percentage rate (APR)
The yearly cost of borrowing expressed as a percentage, without compounding within the year.
Calculator: Loan
Annual percentage yield (APY)
The yearly return on a deposit once interest compounding within the year is included.
Calculator: Certificate Of Deposit
Annuity
A series of equal payments made at regular intervals for a set period.
Calculator: Annuity Income From Lump Sum

B

Basal metabolic rate (BMR)
The energy your body uses at complete rest to keep its vital functions running.
Calculator: BMR
Board foot
A unit of lumber volume equal to a board 12 inches long, 12 inches wide and 1 inch thick.
Calculator: Board Feet
Body fat percentage
The share of total body weight that is fat tissue.
Calculator: Body Fat
Body mass index (BMI)
Weight in kilograms divided by the square of height in metres, a population-level screen of weight for height.
Calculator: BMI
Body surface area (BSA)
The estimated total area of the skin, computed from height and weight and used to scale some medical doses.
Calculator: Body Surface Area
Bond yield
The return a bond pays relative to its price, combining its coupons and the gain or loss at maturity.
Calculator: Bond Yield
Break-even point
The sales volume at which revenue exactly covers fixed and variable costs.
Calculator: Break Even Point
British thermal unit (BTU)
The heat needed to raise one pound of water by one degree Fahrenheit, about 1,055 joules.
Calculator: Btu To Kilowatts

C

Calorie
A unit of energy equal to 4.184 joules; food labels count in kilocalories.
Calculator: Energy Joules To Calories
Capitalization rate
A property's net operating income divided by its value, used to compare rental investments.
Calculator: Cap Rate
Combination
A selection of items in which the order does not matter.
Calculator: Combinations Count
Compound annual growth rate (CAGR)
The constant yearly rate that would take a value from its starting level to its ending level over a period.
Calculator: Cagr Calculator
Compound interest
Interest calculated on the principal plus the interest already earned, so growth accelerates over time.
Calculator: Compound Interest
Credit utilization ratio
The share of your available revolving credit that you are currently using.
Calculator: Credit Utilization Ratio

D

Debt avalanche
A payoff method that puts every extra payment on the debt with the highest interest rate first.
Calculator: Debt Payoff
Debt service coverage ratio
Net operating income divided by the debt payments due over the same period.
Calculator: Debt Service Coverage Ratio
Debt-to-income ratio
Monthly debt payments divided by gross monthly income, used by lenders to judge what you can borrow.
Calculator: Debt To Income Ratio
Density
Mass per unit of volume, such as kilograms per cubic metre.
Calculator: Density Mass Volume
Dew point
The temperature at which air becomes saturated and water vapour starts to condense.
Calculator: Dew Point
Discriminant
The value b² − 4ac of a quadratic equation, whose sign tells whether it has two, one or no real roots.
Calculator: Quadratic Discriminant
Dividend yield
The yearly dividends a share pays divided by its price.
Calculator: Dividend Yield
Dollar-cost averaging
Investing a fixed amount at regular intervals regardless of price, so more units are bought when prices are low.
Calculator: Dollar Cost Averaging

E

Emergency fund
Cash set aside to cover several months of essential expenses after a job loss or an unexpected cost.
Calculator: Emergency Fund
Escape velocity
The minimum speed an object needs to leave a body's gravity without further propulsion.
Calculator: Escape Velocity
Estimated due date
The expected birth date, conventionally 280 days after the first day of the last menstrual period.
Calculator: Pregnancy Due Date

F

Factorial
The product of all positive whole numbers up to n, written n!.
Calculator: Factorial Value
Fahrenheit
A temperature scale on which water freezes at 32 °F and boils at 212 °F.
Calculator: Temperature Celsius To Fahrenheit
Future value
What a sum invested today will be worth at a later date at a given rate of return.
Calculator: Future Value Lump Sum

G

Golden ratio
The proportion of about 1.618 in which the whole is to the larger part as the larger part is to the smaller.
Calculator: Golden Ratio Dimension
Greatest common divisor (GCD)
The largest whole number that divides two numbers without a remainder.
Calculator: Gcd Two Numbers
Gross margin
Revenue minus the cost of goods sold, expressed as a share of revenue.
Calculator: Gross Margin

H

Half-life
The time it takes for half of a quantity to decay.
Calculator: Radioactive Half Life
Heart rate reserve
Maximum heart rate minus resting heart rate, the basis of the Karvonen training method.
Calculator: Heart Rate Reserve
Heart rate zones
Training intensity bands defined as percentages of maximum heart rate.
Calculator: Heart Rate Zones
Heat index
How hot it feels when humidity is combined with the air temperature.
Calculator: Heat Index
Hectare
A unit of area equal to 10,000 square metres, about 2.47 acres.
Calculator: Area Hectares To Acres
Horsepower
A unit of power; one mechanical horsepower equals about 745.7 watts.
Calculator: Power Watts To Horsepower
Hypotenuse
The side opposite the right angle in a right triangle, found with the Pythagorean theorem.
Calculator: Pythagoras Hypotenuse

I

Ideal body weight
A reference weight for a given height and sex from formulas such as Devine or Robinson, not a health target.
Calculator: Ideal Body Weight
Ideal gas law
The relation PV = nRT between the pressure, volume, amount and temperature of a gas.
Calculator: Ideal Gas Law
Inflation
The general rise in prices over time, which reduces what a fixed amount of money can buy.
Calculator: Inflation
Internal rate of return (IRR)
The discount rate at which the net present value of all the cash flows of an investment equals zero.
Calculator: Irr Approximation

K

Kilowatt-hour (kWh)
The energy used by a 1,000-watt load running for one hour, the unit on electricity bills.
Calculator: Kwh From Watts
Kinetic energy
The energy of a moving object, equal to half its mass times the square of its speed.
Calculator: Kinetic Energy

L

Least common multiple (LCM)
The smallest positive whole number that is a multiple of two numbers.
Calculator: Lcm Two Numbers
Litres per 100 km
Fuel consumption measured as the litres a vehicle uses to travel 100 kilometres; lower is more efficient.
Calculator: Fuel Consumption L100km
Loan-to-value ratio (LTV)
The loan amount divided by the appraised value of the property it finances.
Calculator: Loan To Value
Logarithm
The power to which a base must be raised to give a number.
Calculator: Logarithm Change Of Base

M

Macronutrients
The three nutrients that supply energy: protein and carbohydrates at 4 kcal per gram, fat at 9 kcal per gram.
Calculator: Macronutrients
Margin of error
The range above and below a survey result within which the true value is likely to fall at a given confidence level.
Calculator: Margin Of Error
Marginal tax rate
The rate of tax paid on the next dollar of income, as opposed to the average rate on all income.
Calculator: Marginal Vs Effective
Markup
The amount added to cost to set a selling price, expressed as a share of the cost.
Calculator: Markup Vs Margin
Mean arterial pressure
The average pressure in the arteries over one heartbeat, estimated from systolic and diastolic readings.
Calculator: Mean Arterial Pressure
Metabolic equivalent (MET)
The energy cost of an activity as a multiple of the energy used sitting at rest.
Calculator: Calories Burned Met
Molarity
The concentration of a solution in moles of solute per litre of solution.
Calculator: Molarity
Mortgage points
Fees paid upfront to a lender, each equal to 1% of the loan, in exchange for a lower interest rate.
Calculator: Mortgage Points

N

Net present value (NPV)
The sum of an investment's future cash flows discounted to today, minus its initial cost.
Calculator: Net Present Value Single
Net worth
Everything you own minus everything you owe.
Calculator: Net Worth
Newton
The SI unit of force, the force that accelerates one kilogram by one metre per second squared.
Calculator: Force Newtons To Pounds Force

O

Ohm's law
Voltage equals current times resistance (V = I × R).
Calculator: Ohms Law
One-rep max (1RM)
The heaviest load you can lift once with correct form, often estimated from several lighter repetitions.
Calculator: One Rep Max

P

Paint coverage
The wall area one litre or gallon of paint covers in a single coat.
Calculator: Paint Coverage Room
Payback period
The time it takes for the savings or income from an investment to repay its cost.
Calculator: Payback Period
Percent error
How far a measured value is from the true value, as a percentage of the true value.
Calculator: Percent Error
Percentage change
The difference between a new and an old value divided by the old value, times 100.
Calculator: Percentage Change
Percentile rank
The percentage of values in a group that fall below a given value.
Calculator: Percentile Rank From Counts
Permutation
An arrangement of items in which the order matters.
Calculator: Permutations Count
pH
The negative base-10 logarithm of the hydrogen ion concentration; below 7 is acidic, above 7 is basic.
Calculator: Ph From Concentration
Pounds per square inch (psi)
A unit of pressure; one bar equals about 14.5 psi.
Calculator: Pressure Bar To Psi
Power factor
The ratio of real power to apparent power in an AC circuit, between 0 and 1.
Calculator: Power Factor Correction
Present value
What a future sum is worth today once discounted at a given rate.
Calculator: Present Value Future Sum
Price per square foot
A property's price divided by its floor area, used to compare homes of different sizes.
Calculator: Square Foot Price
Principal
The amount borrowed or invested, before any interest.
Calculator: Loan

R

R-value
A material's resistance to heat flow; the higher it is, the better the insulation.
Calculator: Insulation R Value
Rebalancing
Buying and selling holdings to bring a portfolio back to its target allocation.
Calculator: Portfolio Rebalancing
Return on investment (ROI)
The gain from an investment divided by its cost, expressed as a percentage.
Calculator: ROI Calculator
Rise and run
The height of one stair step and its horizontal depth, which together set how comfortable a staircase is.
Calculator: Stair Rise Run
Roof pitch
The steepness of a roof, given as the rise over a 12-unit run or as an angle.
Calculator: Roof Pitch Angle
Rule of 72
A shortcut that estimates the years needed to double money by dividing 72 by the yearly rate in percent.
Calculator: Rule Of 72

S

Sales tax
A tax added to the price of goods and services at the time of purchase, as a percentage of the price.
Calculator: Sales Tax
Savings rate
The share of your income that you save rather than spend.
Calculator: Savings Rate
Simple interest
Interest calculated only on the original principal, never on interest already earned.
Calculator: Simple Interest
Sleep cycle
A sequence of light, deep and REM sleep lasting about 90 minutes that repeats through the night.
Calculator: Sleep Cycles
Slope
The change in y divided by the change in x between two points of a line.
Calculator: Line Slope
Specific heat
The energy needed to raise one kilogram of a material by one degree Celsius.
Calculator: Specific Heat
Standard deviation
A measure of how spread out values are around their mean, the square root of the variance.
Calculator: Standard Deviation Population

T

Total daily energy expenditure (TDEE)
The calories you burn in a day, estimated as resting metabolism multiplied by an activity factor.
Calculator: Calorie

V

Value-added tax (VAT)
A consumption tax charged as a percentage of the price at each stage of sale.
Calculator: Vat Added
VO2 max
The highest rate at which your body can take in and use oxygen during exercise, in millilitres per kilogram per minute.
Calculator: Vo2max Cooper
Voltage drop
The loss of voltage along a wire caused by its resistance, larger for long runs and thin wire.
Calculator: Wire Voltage Drop

W

Waist-to-hip ratio
Waist circumference divided by hip circumference, a marker of how body fat is distributed.
Calculator: Waist To Hip Ratio
Waste factor
The extra material, usually 5 to 15%, added to an order to cover cuts, breakage and mistakes.
Calculator: Tile Count Waste
Weighted average
An average in which each value counts in proportion to its weight.
Calculator: Weighted Average Two Groups
Weighted average cost of capital (WACC)
The average rate a company pays to finance itself, weighting the cost of debt and of equity by their shares.
Calculator: Weighted Average Cost Of Capital
Wind chill
How cold it feels on exposed skin when wind is combined with the air temperature.
Calculator: Wind Chill

Z

Z-score
The number of standard deviations a value lies above or below the mean.
Calculator: Z Score