Calculator Glossary

Health & Body

Activity Multiplier

Factor applied to BMR to estimate TDEE. Ranges from 1.2 (sedentary) to 1.9 (extremely active).

Asia-Pacific BMI Standards

Lower BMI cutoffs for Asian populations: Overweight ≥23, Obese ≥25. Adopted by WHO Western Pacific.

Basal Metabolic Rate (BMR)

The number of calories your body burns at rest to maintain basic life functions like breathing and circulation.

Body Mass Index (BMI)

A measure of body fat based on weight relative to height. Calculated as weight(kg) / height(m)².

Calorie Deficit

Consuming fewer calories than your TDEE. A deficit of ~500 cal/day results in ~0.45 kg (1 lb) weight loss per week.

Estimated Due Date (EDD)

The predicted date of delivery, typically 280 days from LMP. Only ~5% of babies are born on their EDD.

Gestational Age

The age of a pregnancy counted from the first day of the last menstrual period (LMP), measured in weeks and days.

Harris-Benedict Equation

An earlier BMR formula (1919, revised 1984). Less accurate than Mifflin-St Jeor but still widely referenced.

Last Menstrual Period (LMP)

The first day of the most recent menstrual period. Used as the starting point for pregnancy dating (Naegele's rule).

Macronutrients

Three primary nutrient categories: protein (4 cal/g), carbohydrates (4 cal/g), fat (9 cal/g).

Mifflin-St Jeor Equation

The most accurate BMR estimation formula (1990). Separate equations for males and females using weight, height, and age.

Naegele's Rule

A method to estimate the due date: LMP + 280 days (40 weeks). Named after German obstetrician Franz Naegele (1778–1851).

Total Daily Energy Expenditure

Total calories burned per day, combining BMR with physical activity. Used for weight management planning.

Trimester

One of three periods dividing pregnancy: 1st (weeks 1–12), 2nd (weeks 13–26), 3rd (weeks 27–40).

WHO BMI Classification

World Health Organization categories: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), Obese (≥30).

Finance & Investment

Amortization

The process of gradually paying off a loan through scheduled payments. Early payments are interest-heavy.

Amortization Schedule

A table showing each payment's breakdown into principal and interest over the loan's lifetime.

Annual Percentage Rate (APR)

The yearly interest rate without accounting for compounding. Often used in loan disclosures.

Annual Percentage Yield (APY)

The effective annual rate including compounding. APY ≥ APR when compounding occurs more than once per year.

Compounding Frequency

How often interest is calculated and added to principal: monthly, quarterly, semi-annually, or annually.

Compound Interest

Interest calculated on both the initial principal and accumulated interest. The "interest on interest" effect.

Equated Monthly Installment (EMI)

Fixed monthly payment to repay a loan over its tenure. Includes both principal and interest components.

Future Value (FV)

The value of a current sum at a future date, assuming a given growth rate. FV = PV × (1 + r)^n.

Inflation Rate

The rate at which the general price level rises. Real return = nominal return - inflation rate.

Loan Prepayment

Paying off part or all of a loan before its scheduled maturity. May incur prepayment penalties.

Loan Tenure

The total duration of a loan, typically measured in months or years. Longer tenure = lower EMI but more total interest.

Present Value (PV)

The current worth of a future sum of money, discounted at a given interest rate.

Principal

The initial amount of money invested or borrowed, before interest accrues.

Rule of 72

Quick estimation: years to double = 72 / interest rate. At 8% interest, money doubles in ~9 years.

Simple Interest

Interest calculated only on the original principal. Formula: I = P × r × t.

Math & Statistics

Decimal & Fraction

Two ways to represent parts of a whole: 0.25 (decimal) = 1/4 (fraction) = 25% (percentage).

Exponential Growth

Growth where the rate is proportional to the current value. Produces a J-shaped curve over time.

Linear Interpolation

Estimating a value between two known values by assuming a straight line. Used in GPA scale conversion.

Logarithm

The inverse of exponentiation. log_b(x) = y means b^y = x. Used in compound interest calculations.

Percentage

A proportion expressed as a fraction of 100. The symbol % means "per hundred."

Percentage Change

The relative change between two values: ((new - old) / old) × 100. Can be positive (increase) or negative (decrease).

Percentage Point

The arithmetic difference between two percentages. A rate going from 5% to 8% is a 3 percentage point increase.

Percentile

A value below which a given percentage of observations fall. 96th percentile = top 4%.

Proportion

An equation stating two ratios are equal: a/b = c/d. Used in scaling and unit conversion.

Ratio

A comparison of two quantities expressed as a:b or a/b. Different from percentage but related.

Rounding

Approximating a number to a specified precision. Round half up is the most common convention.

Scientific Notation

A way to express very large or small numbers: a × 10^n where 1 ≤ a < 10.

Significant Figures

Digits that carry meaning in a measurement. Trailing zeros after a decimal count; leading zeros don't.

Standard Deviation

A measure of how spread out values are from the mean. Used in statistical grading systems.

Weighted Average

An average where each value has a different importance (weight). Used in GPA calculation.

Calendar & Time

Chinese Zodiac (十二支)

12-year cycle of animals: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig.

Earthly Branches (지지 / 地支)

12 cyclical elements corresponding to zodiac animals: 子丑寅卯辰巳午未申酉戌亥.

Heavenly Stems (천간 / 天干)

10 cyclical elements: 甲乙丙丁戊己庚辛壬癸. Combined with Earthly Branches for the 60-year cycle.

Intercalary Month (윤달)

A leap month inserted in lunisolar calendars to keep lunar and solar years aligned. Occurs ~7 times per 19 years.

Japanese Era System (和暦)

Japan's imperial year numbering: Meiji (1868), Taishō (1912), Shōwa (1926), Heisei (1989), Reiwa (2019).

Kazoe-doshi (数え年)

Japanese counting age system where a person is 1 at birth and gains a year each New Year. Same as Korean 세는나이.

Korean Lunar New Year (설날)

The most important Korean holiday, based on the lunisolar calendar. Typically late January to mid-February.

Leap Year

A year with an extra day (Feb 29) to synchronize the calendar year with the astronomical year. Every 4 years, except centuries not divisible by 400.

Lunar Calendar

A calendar based on the moon's phases. Each lunar month is ~29.5 days. Used in East Asian cultures.

Lunisolar Calendar

A calendar combining lunar months with solar year adjustments via intercalary (leap) months. Used in Chinese, Korean, Japanese traditions.

Reiwa Era (令和)

Current Japanese era since May 1, 2019. Named from Man'yōshū poetry: "beautiful harmony."

Sexagenary Cycle (干支 / 간지)

60-year cycle combining 10 Heavenly Stems (천간) and 12 Earthly Branches (지지).

Solar Calendar

A calendar based on Earth's orbit around the Sun. The Gregorian calendar (365/366 days) is solar.

Taiyaku (大厄)

The "great unlucky year" — the peak yakudoshi. Age 42 for males (四十二 = 死に = death), age 33 for females (三十三 = 散々 = disaster).

Yakudoshi (厄年)

Japanese tradition of unlucky years. Males: 25, 42 (大厄), 61. Females: 19, 33 (大厄), 37, 61. Uses kazoe-doshi (counting age).

Korean Real Estate

Acquisition Tax (취득세)

Tax paid when purchasing real estate in Korea. 1–3% for first home, up to 12% for 3rd+ home in regulated areas.

Basic Deduction ₩250만원 (기본공제)

₩2.5M basic deduction applied before capital gains tax calculation on real estate profits.

Capital Gains Tax (양도소득세)

Tax on profit from selling real estate in Korea. Progressive rates 6–45% with long-term holding deductions.

Comprehensive Real Estate Tax (종합부동산세)

Annual tax on high-value property holdings exceeding exemption threshold (single home: ₩1.2B).

Housing Savings Account (주택청약종합저축)

Specialized savings account required for housing subscription. Points accumulate per year of membership.

Housing Subscription (청약)

Korean system where applicants compete for new apartment units using a points-based system.

Housing Subscription Points (청약가점)

Scoring system (max 84 points) based on homelessness period, dependents, and savings account years.

Jeonse (전세)

Korean deposit-based rental: tenant pays a large lump-sum deposit (50–80% of property value), landlord returns it at lease end. No monthly rent.

Jeonse Conversion Rate (전월세 전환율)

The rate used to convert between jeonse deposit and monthly rent. Currently capped at 3.0% + base rate (total ~6.5%).

Long-Term Holding Deduction (장기보유특별공제)

Tax deduction for holding property long-term. Up to 80% for single-home owners (10+ years + residency).

Realtor Fee (중개수수료)

Commission paid to real estate agents in Korea. Capped by law, varying by transaction price and type.

Regulated Area (조정대상지역)

Areas designated by the Korean government with stricter real estate regulations and higher multi-home tax rates.

Rural Education Tax (농어촌특별세/교육세)

Surtaxes added on top of acquisition tax. Rural: 0.2%, Education: 0.1–0.4%.

Single Home Owner (1세대 1주택)

Tax status in Korea where a household owns exactly one home. Eligible for significant tax benefits.

Wolse (월세)

Korean monthly rental: tenant pays a smaller deposit plus monthly rent. More common as interest rates rise.

Korean Life & Culture

Chuseok (추석)

Korean harvest festival, celebrated on the 15th day of the 8th lunar month.

Conscription (징병제)

Mandatory military service system. Korea requires all able-bodied males aged 18–35 to serve.

CSAT / 수능 (대학수학능력시험)

Korea's national college entrance exam, taken by ~500K students annually in November. Scored on 9-grade relative scale.

CSAT 9-Grade System (등급제)

Relative grading: Grade 1 (top 4%), Grade 2 (4–11%), ... Grade 9 (bottom 4%). Applied per subject.

Discharge Date (전역일)

The specific date when military service ends, calculated from entry date + service duration - 1 day.

International Age (만나이)

Korea's official age system since June 2023. Age from birth date, increments on birthday (same as international).

Korean Counting Age (세는나이)

Traditional Korean age: +1 at birth, +1 every Lunar New Year. Still used colloquially despite legal change.

Korean GPA (학점)

Korean universities use 4.5, 4.3, or 4.0 scale. Most common is 4.5 (A+ = 4.5).

Korean Year Age (연나이)

Current year minus birth year. Used in some Korean laws (e.g., youth protection, alcohol purchase).

Military Branches (군종)

Korea's five service branches: Army (육군), Navy (해군), Air Force (공군), Marines (해병대), Social Service (사회복무).

Military Service (군복무)

Mandatory military service for Korean males. Duration varies by branch: Army 18mo, Navy 20mo, Air Force 21mo.

Pyeong (평)

Traditional Korean area unit. 1 pyeong = 3.306 m² ≈ 35.58 sq ft. Commonly used for apartment sizes.

School Record / 내신 (학교생활기록부)

Korean high school GPA used for university admissions. Also uses 9-grade relative system.

Seollal (설날)

Korean Lunar New Year. One of the two major Korean holidays. Date varies (Jan–Feb).

Social Service (사회복무)

Alternative military service in Korea for those with health conditions. Duration: 21 months.

Japanese Culture

Ato-yaku (後厄)

The year after the main unlucky year. The "lingering" unlucky period.

Danchima (団地間)

Public housing tatami: 170 × 85 cm = 1.445 m². The smallest variant, used in danchi apartments.

Edoma (江戸間)

Tokyo-style tatami: 176 × 88 cm = 1.549 m². Standard in the Kantō region.

Heisei Era (平成)

Japanese era 1989–2019. Known as the "Lost Decades" economically, but cultural stability.

Hon-yaku (本厄)

The main unlucky year itself. Age 42 (males) or 33 (females) is the most significant.

Kyoma (京間)

Kyoto-style tatami: 191 × 95.5 cm = 1.824 m². The largest regional variant.

Mae-yaku (前厄)

The year before the main unlucky year. Period of increasing caution.

Meiji Era (明治)

Japanese era 1868–1912. Period of rapid modernization and Westernization.

Reiwa Era (令和)

Current era since May 1, 2019. Emperor Naruhito. First era name from Japanese (not Chinese) literature.

Shōwa Era (昭和)

Japanese era 1926–1989. The longest era, covering WWII and Japan's economic miracle.

Taishō Era (大正)

Japanese era 1912–1926. Known for democratic movements and cultural flourishing.

Tatami (畳)

Traditional Japanese floor mat unit. Size varies by region: Kyoma (1.82 m²), Edoma (1.55 m²).

Tsubo (坪)

Japanese area unit. 1 tsubo = 3.306 m² ≈ 2 tatami mats. Still used in real estate.

Wareki System (和暦制度)

Japan's era-based calendar system. Each emperor's reign defines a new era. Official use alongside Gregorian.

Yakudoshi Tradition (厄年の伝統)

Belief that certain ages bring misfortune. Rooted in Shinto/Buddhist tradition. People visit shrines for yakubarai (厄払い).