Formula Hub

The arithmetic mean formula calculates the central average value of a sample dataset by summing all observation values and dividing by the total sample count.

The attendance percentage formula calculates the proportion of classes attended out of total classes conducted. To maintain a required target criteria (such as 75%), bunk guidance calculates maximum skippable lectures $B = \lfloor \frac{N_{\text{attended}} - T \times N_{\text{total}}}{T} \rfloor$, while recovery guidance calculates required consecutive lectures $R = \lceil \frac{T \times N_{\text{total}} - N_{\text{attended}}}{1 - T} \rceil$.

The Widmark formula estimates Blood Alcohol Concentration by dividing the total grams of alcohol consumed by body weight adjusted for a gender-based body-water distribution constant, then subtracting the amount the body has already metabolized over elapsed time at an average elimination rate. It is widely used to give a rough estimate of impairment level, though it is not a substitute for an actual breathalyzer or blood test.

Body Mass Index (BMI) is a simple, widely used metric to estimate whether a person has a healthy body weight relative to their height. BMI categorizes individuals into underweight (under 18.5), normal weight (18.5 - 24.9), overweight (25 - 29.9), and obese (30 and above). It acts as a screening tool to identify possible weight problems for adults.

Basal Metabolic Rate (BMR) represents the minimum number of calories your body needs to function at rest (e.g. breathing, circulation, cell production, temperature regulation). BMR is estimated using the Mifflin-St Jeor equation, which is widely considered the most accurate standard for calorie planning.

The U.S. Navy Method estimates body fat percentage from simple circumference measurements rather than calipers or DEXA scans, using a regression formula developed by Hodgdon & Beckett that predicts body density from waist, neck, hip (for women), and height, then converts that density to a body fat percentage using the Siri equation (the 495/D − 450 term).

The Mosteller formula is the simplest and most widely used method for estimating Body Surface Area, a measurement used clinically for drug dosing (especially chemotherapy) and for normalizing physiological measurements like kidney filtration rate (eGFR). Several other validated formulas exist (Du Bois, Haycock, Gehan & George, Boyd), each using slightly different regression coefficients, and are often averaged together since no single formula is universally agreed upon as most accurate.

The break-even point calculates the exact sales volume in units or revenue required to cover total operational expenses, yielding zero net profit and zero net loss.

The break-even selling price formula calculates the minimum price per unit required to cover all production costs for a target sales volume.

Built-Up Area adds the thickness of walls and any balcony space to the Carpet Area, representing a unit's full physical footprint. Since most listings and price quotes reference Built-Up (or Super Built-Up) Area rather than Carpet Area, this formula helps buyers convert between the two to estimate real usable space or verify a quoted built-up figure.