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Gamma Shielding Half-Value Layer (HVL) & Buildup Formula
Calculate Lead/Concrete Half-Value Layer HVL (cm), Tenth-Value Layer TVL (cm), Narrow-Beam Uncollided Dose Rate (mSv/hr), and Broad-Beam Compton-Buildup Dose Rate D (mSv/hr).
Read the guide →Statistical AnalysisGamma Waiting-Time Quantile & SLA Buffer Formula (GAMMA.INV Wilson-Hilferty Cube-Root)
Calculate multi-stage Gamma and Erlang waiting-time quantiles (GAMMA.INV) using exact exponential inversion for shape k = 1 and the Wilson-Hilferty cube-root transformation for multi-stage queues.
Read the guide →ScienceGamow Quantum Tunneling Factor, Gamow Energy & Stellar Gamow Peak
Calculate nuclear Gamow Energy E_G = 2 * mu_keV * (PI() * alpha * Z1 * Z2)^2, Coulomb barrier tunneling probability P = EXP(-SQRT(E_G / E)), and thermonuclear Gamow Peak energy E_0 = (SQRT(E_G) * kT / 2)^(2/3).
Read the guide →Date & TimeGantt chart formula: build a dynamic project timeline grid in cells
Populate calendar or weekly Gantt timeline bars with mixed-reference AND comparisons and compute overall project start and finish dates.
Read the guide →Switch-Mode Power Magnetics, Gapped Ferrite Buck/Flyback Inductors & ReluctanceGapped Ferrite Core Inductor Reluctance, AL & Isat Formula
Calculate Total Series Magnetic Reluctance R_tot (MA/Wb), Gapped Inductance Factor AL (nH/turn²), Winding Inductance L (uH), and Hard-Saturation Peak Current Isat (A).
Read the guide →Financial ModelingGarman-Kohlhagen FX Currency Option Pricing & Covered Interest Parity
Price European FX calls and puts under Garman and Kohlhagen (1983) by discounting foreign currency spot at r_f and domestic strike at r_d, verified via FX put-call parity.
Read the guide →EngineeringGas Mean Free Path & Knudsen Number (Kn) Vacuum Flow Regimes
Estimate an ideal hard-sphere gas mean free path, calculate Kn=lambda/L, and compare it with explicitly defined rarefaction ranges using absolute pressure and consistent length units.
Read the guide →Metallurgical Surface Heat Treatment, AMS 2759/10 Controlled Gas Nitriding & KN PotentialGas Nitriding Potential KN & Case Depth Formula
Calculate Retort Ammonia Partial Pressure p_NH3 (atm), Hydrogen Partial Pressure p_H2 (atm), Lehrer Nitriding Potential KN (atm^-0.5), and Parabolic Nitrided Case Depth (mm).
Read the guide →Engineering & Fluid MechanicsGates-Gaudin-Schuhmann (GGS) Particle Size Formula: Power-Law Passing & P80 Interpolation
Characterize jaw/cone crusher products and fine mineral tails using the Gates-Gaudin-Schuhmann power law P(d) = 100 * MIN(1, (d / k)^m) and solve directly for 80%-passing size P80 = k * 0.8^(1/m).
Read the guide →Charts & Data VisualizationGauge (Speedometer) Chart Formula: 180-Degree Doughnut Dial & Pointer Needle XY
Build a semicircular KPI Gauge / Speedometer Chart by pairing a 360-degree Doughnut dial (Red + Amber + Green = 180 degrees plus a transparent 180-degree bottom half) with a clamped pointer angle theta = 180 * (1 - p) and needle tip (COS, SIN).
Read the guide →Environmental Engineering & Air Quality ModelingGaussian Air Plume Ground Concentration Formula
Calculate steady-state downwind ground-level centerline pollutant concentration C(x, 0, 0) = (Q / (PI()*u*sigma_y*sigma_z)) * EXP(-H^2 / (2*sigma_z^2)) with ground eddy reflection.
Read the guide →Engineering & ScientificGaussian Error Function & Complementary Tail (ERF & ERFC) for Fickian Diffusion & BER
Evaluate erf(x) and erfc(x) = 1 - erf(x) to 6-decimal accuracy for semi-infinite Fick's Second Law dopant/heat diffusion profiles and BPSK digital communication bit-error rates.
Read the guide →Semiconductor Device Physics, Ion Implantation & CMOS DopingGaussian Ion Implantation Peak Dopant & Junction Depth Formula
Calculate Peak Implanted Dopant Concentration N_p (10^18 cm^-3), Wafer Surface Concentration N(0) (10^18 cm^-3), Metallurgical p-n Junction Depth x_j (nm), and Peak-to-Background Ratio.
Read the guide →MathGCD function: simplify aspect ratios and find largest equal batch sizes
Find the greatest common divisor of two or more integers with GCD to reduce screen or recipe ratios to lowest whole terms.
Read the guide →Clinical Medicine & PhysiologyGehan-George (1970) & Boyd (1935) Body Surface Area (BSA) Formula: Oncology Dosing
Calculate high-sample-size oncology Body Surface Area (m^2) for mg/m^2 cytotoxic chemotherapy dosing using Edmund A. Gehan & Stephen L. George’s (1970, NCI standard) 401-subject power law and Edith Boyd’s (1935) log-weight allometric equation.
Read the guide →Engineering & ScienceGeiger-Nuttall Law: Alpha-Decay Half-Life vs. Q-Value Tunneling Formula
Calculate base-10 log half-life log10(T_1/2) = (A_GN / SQRT(Q_alpha)) + B_GN across Polonium and actinide isotopes to see why doubling alpha decay energy spans 14+ orders of magnitude in half-life.
Read the guide →Chemical, Process & Catalysis EngineeringGeldart Powder Fluidization Group (C, A, B, D) Classifier Formula: Size & Density Map
Classify gas-solid fluidized bed powders into Derek Geldart’s (1973) four hydrodynamic regimes — Group C (Cohesive), Group A (Aeratable), Group B (Sand-Like Bubbling), and Group D (Spoutable) — from Sauter mean diameter d_sv (um) and density difference Delta_rho.
Read the guide →Rock Mechanics, Open-Pit Slope Stability & Deep Caverns, Hoek-Brown 2002 CriterionGeneralized Hoek-Brown Rock Mass GSI & Strength Formula
Calculate Generalized Hoek-Brown Reduced Constant mb, Rock Mass Cohesion Parameter s, Non-Linear Exponent a, and Triaxial Major Principal Failure Stress sigma_1 (MPa).
Read the guide →Date & TimeGenerate & Filter Gregorian Leap Years Accurately Across Century Boundaries
Build a leap-year list that avoids the naive +4 century trap on 1900 and 2100 using exact 4/100/400 modular rules, MONTH(DATE(y,2,29))=2, and FILTER.
Read the guide →Date & TimeGenerate & Snap Time Slots at Specific Minute Intervals (15, 20, or 30 Min)
Compute total appointment slots in a shift, map any integer slot index to exact HH:MM clock time, and snap arbitrary arrival timestamps upward to the next scheduled interval.
Read the guide →Dates, Time & SchedulesGenerate a Dynamic Sequence of Time Slots Every N Minutes (SEQUENCE & TIME)
Spill an exact clinic, interview, or conference schedule of N appointment slots spaced every M minutes using SEQUENCE(Slots, 1, TIME(Start_Hr, Start_Min, 0), Interval_Min / 1440).
Read the guide →Dates & SchedulesGenerate a Dynamic Sequence of Upcoming Weekend Dates (WEEKDAY & SEQUENCE)
Anchor on the first Saturday on or after any start date using WEEKDAY(start, 2) modular arithmetic and step forward in 7-day increments with SEQUENCE.
Read the guide →Dates, Time & SchedulesGenerate a Dynamic Sequence of Years & Multi-Year Forecast Headers (SEQUENCE)
Spill vertical or horizontal N-year financial forecast timelines from a single Start_Year and Horizon_Years input using SEQUENCE(N, 1, Start_Year, 1) or SEQUENCE(1, N, Start_Year, 1).
Read the guide →Date & TimeGenerate a Recurring Custom Weekday Schedule (Mon/Wed/Fri & Tue/Thu Cadence)
Compute the exact calendar date of the Nth recurring class, clinic, or delivery session on a custom multi-day weekly pattern such as Monday/Wednesday/Friday using quotient-and-remainder cycle math.
Read the guide →Dates, Time & SchedulesGenerate a Rolling Sequence of Month-Start & Month-End Dates (EDATE & EOMONTH)
Step forward or backward any number of calendar months from a start date using EDATE(DATE(Year, Month, 1), Offset) for exact 1st-of-month headers and EOMONTH(..., Offset) for leap-year-safe month-end closing dates.
Read the guide →MathGenerate Combination Lock & Zero-Padded PIN Codes (SEQUENCE & MOD)
Count independent dial combinations, decode a three-dial state, and generate every four-digit decimal code with leading zeros. Includes validated inputs and a SEQUENCE list with a text-formatting column.
Read the guide →Date & TimeGenerate Dates & Workdays Between Two Dates (RANDBETWEEN & WORKDAY)
Sample calendar dates or Monday–Friday workdays within inclusive date bounds. Exclude holidays, guard empty workday pools, and use a fixed fraction in [0,1) for repeatable examples.
Read the guide →Date & TimeGenerate Drift-Free Future Time Intervals and Slot Schedules (1440-Minute Anchor Math)
Generate N-minute appointment, shift, or dispatch intervals from an anchor start time without cumulative floating-point rounding drift by indexing off Start + (Slot - 1) * Minutes / 1440.
Read the guide →TextGenerate hierarchical WBS outline numbering (1, 1.1, 1.2, 1.2.1, 2) by level
Build a three-level outline code from explicit depth values and running counters. Refill the formulas when extending or restructuring the list.
Read the guide →Math & StatisticalGenerate Repeating Block Numbers Every N Rows (1,1,1, 2,2,2)
Assign repeating pallet, carton, or cohort group IDs (1, 1, 1, 2, 2, 2...) and within-block slot numbers (1, 2, 3, 1, 2, 3...) every N rows using INT and MOD.
Read the guide →Statistical & Clinical AnalysisGeorge-Desu & Rubinstein-Lachin-Foulkes Survival Trial Sample Size: Accrual & Follow-Up
Calculate required Phase III survival events via George & Desu (1974) d = CEILING(4*(z_alpha/2 + z_beta)^2 / (LN(HR))^2, 1) and convert events into enrolled patients N under uniform accrual A and additional follow-up F.
Read the guide →Statistical & Clinical AnalysisGeriatric Nutritional Risk Index (GNRI) Formula: Bouillanne Albumin & Lorentz Ideal Weight
Calculate Olivier Bouillanne et al.’s (2005) Geriatric Nutritional Risk Index GNRI = 1.489 * Albumin_gL + 41.7 * MIN(1, Weight / Lorentz_Ideal_Weight) and classify Major (< 82), Moderate (82 to < 92), Low (92 to <= 98), and Normal (> 98) nutrition-related mortality risk.
Read the guide →Quantitative Finance & Real OptionsGeske Call-on-Call Compound Option Exercise Threshold and Bound
Evaluate staged R&D and M&A call-on-call options in Excel and Arte Sheets by testing Geske’s (1979) T_1 residual Black-Scholes exercise condition C_BSM(S_T1, K_2, T_2 - T_1) >= K_1.
Read the guide →Lookup & ReferenceGet address of first and last cell in a range (ADDRESS, ROW, ROWS, COLUMN & COLUMNS)
Return the top-left C3, bottom-right E6, or full $C$3:$E$6 address text for a rectangular range.
Read the guide →Date & TimeGet Calendar Date for the Nth Day of the Year (Leap-Aware DATE Overflow)
Convert an ordinal day-of-year integer (1–366) and 4-digit year into an exact calendar date—automatically adjusting for February 29 in leap years—using DATE(year, 1, n).
Read the guide →Lookup & ReferenceGet Cell Value & Coordinate String at Given Row and Column (INDEX + ADDRESS)
Retrieve any cell’s exact value without volatile INDIRECT by pairing INDEX(B2:D5, G2, G3) with ADDRESS(Row_Offset + G2, Col_Offset + G3, 4) for audit trail reporting.
Read the guide →Lookup & ReferenceGet Column Name from Index & Column Position from Header (INDEX / MATCH)
Retrieve the nth column header label from a table header row with INDEX(A1:E1, 1, k) and find the 1-based column index of any named field with MATCH(name, A1:E1, 0).
Read the guide →Date & TimeGet day name from a date: locale-safe weekday labels with WEEKDAY and CHOOSE
Turn any calendar date into "Monday".."Sunday" or "Mon".."Sun" using WEEKDAY(date, 2) + CHOOSE so formulas never break across locales.
Read the guide →Date & TimeGet days in month: leap-year safe month length and daily proration
Combine DAY and EOMONTH(date, 0) to return 28, 29, 30, or 31 for any calendar date and prorate monthly fees accurately.
Read the guide →Date & TimeGet days, hours, and minutes between two timestamps ("3d 15h 30m")
Calculate multi-day incident or transit durations into clean "Xd Yh Zm" labels without losing 24-hour rollovers or suffering floating-point minute drift.
Read the guide →Date & TimeGet Earliest Start & Latest Finish Project Dates by Phase (MINIFS & MAXIFS)
Summarize valid task dates by phase using MINIFS and MAXIFS, with explicit checks for missing tasks, incomplete dates and reversed date ranges.
Read the guide →Lookup & ReferenceGet First & Last Numeric or Text Value in a Sparse Row
Find the leftmost and rightmost numbers or nonempty text entries in a mixed row, preserving column order and distinguishing zero, numeric text and empty-string formulas.
Read the guide →Lookup & ReferenceGet First & Last Text Value in a Mixed Range (Wildcard XLOOKUP)
Extract the first or last non-empty text entry from a column or row mixed with numbers and blanks using XLOOKUP("?*", range, range, "No Text Found", 2, 1) and reverse search_mode -1.
Read the guide →Lookup & ReferenceGet first and last entry by month and year (FILTER, TAKE, DATE & EOMONTH)
Return the first and last source-row balances within a selected calendar month, including timestamps on its final day.
Read the guide →Lookup & ReferenceGet First or Last Match Where Cell Contains Text (Wildcard XLOOKUP)
Retrieve either the earliest or most recent transaction whose description contains a target keyword by pairing XLOOKUP match_mode = 2 (wildcards) with search_mode = 1 or -1.
Read the guide →Lookup & ReferenceGet First Text Value in a Row or Column (Skipping Blanks & Numbers)
Extract the first non-empty text entry across mixed blank, numeric, and text cells using wildcard XLOOKUP("?*", B2:F2, B2:F2, "No Text Found", 2) or INDEX + MATCH("?*", ...).
Read the guide →Date & TimeGet fiscal quarter and fiscal year from a date (any start month)
Convert transaction dates into calendar quarters (Q1–Q4) or shifted fiscal quarters and fiscal years (April, July, or October starts).
Read the guide →Dates & TimeGet Last Specific Weekday of Month (Last Friday, Monday, or Thursday)
Calculate the exact date of the last Friday, Monday, or any target weekday (1=Sun to 7=Sat) in a month using EOMONTH(date, 0) - MOD(WEEKDAY(EOMONTH(date, 0)) - target_dow + 7, 7).
Read the guide →Date & TimeGet Monday of the week from any date (weekly cohort grouping)
Roll daily timestamps back to the Monday (or Sunday) starting their week using Date - WEEKDAY(Date, 2) + 1.
Read the guide →Date & TimeGet month name from a date: locale-safe full and 3-letter labels
Extract English full ("April") or abbreviated ("Apr") month names reliably across locales with CHOOSE and MONTH.
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