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1,033 calculators · 53 categories
Medical Calculators
Clinical scores, dosing, unit conversions and lab interpretation, each with the rule it follows and where that rule comes from.
CKD-EPI 2021 Creatinine eGFR CalculatorEstimate GFR from creatinine, age and sex using the 2021 race-free CKD-EPI equation, the current standard for adults.Renal Function & eGFRCockcroft-Gault Creatinine Clearance CalculatorEstimate creatinine clearance in mL/min — the equation most drug labels specify for renal dose adjustment.Renal Function & eGFRAnion Gap CalculatorCalculate the serum anion gap from sodium, chloride and bicarbonate — with the interval that belongs to this…Acid-Base & Blood GasCorrected Calcium CalculatorAdjust total serum calcium for a low albumin using the traditional correction formula, and see why it should…Bone & Mineral MetabolismBody Surface Area (BSA) CalculatorCalculate BSA by the Mosteller or Du Bois formula, the basis of most chemotherapy dosing and of eGFR…Tumour Markers & Oncology LabsLDL Cholesterol Calculator (Friedewald)Estimate LDL cholesterol from total cholesterol, HDL and triglycerides using the Friedewald equation — and see the four…Lipids & Cardiovascular Risk LabsCURB-65 Score CalculatorScore community-acquired pneumonia severity from five bedside criteria, and see what the score deliberately leaves out.Infectious Disease & Sepsis LabsWells Score for DVT CalculatorEstimate the clinical probability of deep vein thrombosis with the Wells score, using the two-level DVT-unlikely / DVT-likely…Coagulation & ThrombosisA-a Gradient CalculatorCalculate the alveolar-arterial oxygen gradient to distinguish hypoxaemia from V/Q mismatch or shunt from hypoxaemia caused by hypoventilation…Acid-Base & Blood GasAlbumin-Corrected Anion Gap CalculatorCorrect the anion gap for hypoalbuminaemia, which lowers the measured gap and can hide a clinically significant high-anion-gap…Acid-Base & Blood Gas
Acid-Base & Blood Gas 22Addiction & Mood Screening 7Adrenal & Steroid Hormones 24Amino Acids, Metabolic & Newborn Screening 33Analgesia & Opioid Equivalence 8Antimicrobial PK/PD 8Audiology & Hearing Assessment 8Blood Bank & Transfusion Medicine 20Bone & Mineral Metabolism 21CSF & Body Fluid Analysis 31Cardiac Markers 19Cardiology & ECG 8Chemistry & Electrolytes 29Clinical Nutrition & Metabolic Support 8Coagulation & Thrombosis 23Comorbidity & Cognitive Screening 8Dermatology Severity & Skin Lesions 8Diabetes, Glucose & Insulin Resistance 33Fracture & Musculoskeletal Classification 16Haematological Malignancy Prognosis 8Haematology — Red Cell & Indices 24Haematology — White Cell & Inflammatory Ratios 24Haemodynamics & Circulatory Assessment 8Immunology, Autoantibodies & Complement 36Infectious Disease & Sepsis Labs 30Iron Studies 24Lab Utilities, Dilutions & Unit Tools 21Laboratory Quality, Statistics & Interpretation 24Lipids & Cardiovascular Risk Labs 30Liver & Gastrointestinal 49Mechanical Ventilation & Oxygenation 8Molecular, Genetics & Specimen Calculations 24Neonatal & Paediatric Laboratory 24Neurology & Neurocritical Care 8Obstetric & Fetal Assessment 16Oncology Dosing & Response 8Ophthalmic Optics & Visual Function 16Paediatric & Neonatal Acute Scores 7Perioperative Risk Assessment 14Pituitary, Gut & Metabolic Hormones 22Pulmonary Function Testing 8Renal Function & eGFR 27Reproductive, Fertility & Pregnancy Labs 30Sleep Study Metrics 8Therapeutic Drug Monitoring 30Thyroid 24Toxicology & Poisoning 34Trauma & Burns Assessment 8Tumour Markers & Oncology Labs 22Urine Chemistry & Urinalysis 40Urology & Stone Disease 8Vascular Assessment 8Vitamins, Trace Elements & Nutrition Labs 27
154 calculators · 12 categories
Finance Calculators
Loans, savings, investments and salary, in twelve currencies, with the formula and the assumptions on the page.
EMI CalculatorWork out the monthly instalment on a home, car, personal or education loan from the amount, interest rate…Loans & EMISIP CalculatorEstimate what a monthly SIP could grow to at an assumed annual return, and how much of it…Investing & Mutual FundsFD Calculator (Fixed Deposit)What a fixed deposit pays: the maturity value if interest is reinvested, or the interest paid out each…Savings & DepositsHome Loan Eligibility CalculatorHow large a home loan can you afford? Start from the EMI you are comfortable paying — or…Loans & EMICompound Interest CalculatorGrow a lump sum, with optional monthly additions, at any compounding frequency — and see how much of…Savings & DepositsGratuity Calculator (India)Gratuity under India's Code on Social Security, 2020: 15 days' wages for each year of service, using your…Salary & Employee BenefitsPPF Calculator (Public Provident Fund)What a Public Provident Fund account could grow to over its 15-year term, year by year — and…Savings & DepositsGST Calculator (India)Add GST to a price, or take it out of a GST-inclusive price, and see the split into…Business & PricingBreak-Even CalculatorHow many units you must sell to cover your fixed costs, the sales revenue that takes, and how…Business & PricingBurn Rate and Runway CalculatorHow fast a business is spending its cash, and how many months the money in the bank lasts…Business & Pricing
173 calculators · 20 categories
Electronics Calculators
From Ohm's law to solar sizing, most with a live circuit diagram that redraws as you type.
Ohm’s Law CalculatorEnter any two of voltage, current, resistance and power and get the other two, with units scaled automatically…Basic Circuit LawsLED Series Resistor CalculatorThe resistor an LED needs: exact value, the next standard value up, the current you actually get with…LEDs & LightingResistor Color Code CalculatorPick the colour of each band on a 4-, 5- or 6-band resistor and read its resistance, the…Component Codes & ValuesElectricity Consumption Calculator (Units per Month)Add up to six appliances — watts, hours a day and how many you own — and see…Wiring, Cables & Home ElectricalInverter Battery Backup Time CalculatorHow many hours your inverter will run on its battery: from the bank's Ah and voltage, the usable…Batteries, UPS & SolarVoltage Drop CalculatorThe voltage a cable loses at your load current — in volts and as a percentage — with…Wiring, Cables & Home Electrical555 Timer Astable CalculatorFrequency, period, high and low times and duty cycle for a 555 in astable mode — or work…Timers, Oscillators & DigitalSolar Panel Size CalculatorHow many kilowatts of panels your house needs: from your daily units, the peak sun hours where you…Batteries, UPS & SolarMotor Full Load Current CalculatorFull-load amps from a motor's nameplate kW or HP, with efficiency and power factor in the right places…Motors & DrivesHP to kW ConverterConvert horsepower to kilowatts and back — with all three definitions kept apart, because mechanical, metric and electrical…Electrical Unit Converters
Basic Circuit Laws 10Batteries, UPS & Solar 14Capacitors, Inductors & Reactance 9Component Codes & Values 4DC-DC Converters 11EMI, EMC & Filters 14Electrical Unit Converters 4Filters & Frequency Response 7LEDs & Lighting 5Linear Power & Regulators 3Magnetics & Transformers 11Motors & Drives 14Op-Amps & Analog 6PCB Design 8Power Semiconductors & Thermal 11RF, Antennas & Transmission Lines 10Sensors & Thermistors 6Signals, Audio & Measurement 7Timers, Oscillators & Digital 7Wiring, Cables & Home Electrical 12
73 calculators · 12 categories
Unit Converters
Conversions that need a table behind them — cups to grams by ingredient, land units by state, shoe sizes by country, wire and sheet gauges.
Cups to Grams Converter (by Ingredient)Convert cups, tablespoons, teaspoons and millilitres to grams and ounces for 26 named ingredients, in both directions, using…Kitchen & CookingIndian Land Area ConverterConvert between every Indian land unit — cent, guntha, bigha, katha, biswa, kanal, marla, ground, ankanam, dismil, chatak,…Land & Area MeasureOven Temperature Converter (°C, °F, Gas, Fan)Convert between °C, °F, gas mark and a fan oven setting in any direction, with the exact gas-mark…Kitchen & CookingWire Gauge Converter — AWG and SWGAWG, SWG, millimetres of diameter, square millimetres of area and circular mils, in both directions — and the…Wire, Textile & Trade GaugesShoe Size ConverterUS, UK, EU, Japanese and centimetre shoe sizes, for men, women and children, converted through the one quantity…Clothing, Shoe & Body SizingSalt Conversion Calculator (Table, Kosher, Sea)Convert between table salt, Morton coarse kosher, Diamond Crystal kosher and fine sea salt by volume and by…Kitchen & CookingSheet Metal Gauge ConverterGauge number to thickness in millimetres and inches, and back — for uncoated steel, galvanised steel, stainless steel,…Wire, Textile & Trade GaugesBigha Converter — State by StateHow big is a bigha? Between 6,806 and 27,225 square feet, depending on which state's revenue record the…Land & Area MeasureMeat Cooking Temperature Converter (°C, °F, Doneness)Internal temperatures for meat by food and by doneness, in °C and °F both ways, with the USDA…Kitchen & CookingDrill Bit Size ConverterFractional inch, number (1–80), letter (A–Z) and metric drill sizes, all converted through diameter and all four directions…Wire, Textile & Trade Gauges
76 calculators · 10 categories
Mechanical Calculators
Machine element design — chain and belt drives, gears, fasteners, shafts and keys, bearings, springs, fits and tolerances. The dimension you need before you can draw the part.
Chain Length and Center Distance CalculatorChain length from a centre distance and centre distance from a chain length, with the even link count…Chain, Belt & Sprocket DrivesRoller Chain Selection CalculatorWhich chain size, from the power and the speed — by the route that can be verified: design…Chain, Belt & Sprocket DrivesSprocket Geometry CalculatorEvery diameter a sprocket drawing needs, from the tooth count, the pitch and the roller — pitch, outside,…Chain, Belt & Sprocket DrivesChain Wear and Elongation CalculatorMeasure a length across a known number of pitches and this returns the elongation, the remaining life, the…Chain, Belt & Sprocket DrivesBelt Tension and Shaft Load CalculatorHow tight, measured the way you can actually measure it — deflect the span by a sixty-fourth of…Chain, Belt & Sprocket DrivesDrive Service Factor CalculatorThe service factor and the design power, from three published families at once — the chain table Renold…Chain, Belt & Sprocket DrivesBolt Torque CalculatorT = K·F·d, with the nut factor computed from friction rather than looked up, the torque split into…Bolted Joints & TorqueHex Head Bolt Dimensions CalculatorAcross flats, across corners, head height, washer face, thread length and the plain shank left under it, for…Fastener DimensionsCounterbore and Countersink CalculatorCounterbore diameter and depth for a socket head, countersink top diameter and depth for a flat head, the…Fastener DimensionsWasher Dimensions CalculatorBore, rim, thickness and — the number that actually decides the choice — the bearing area of the…Fastener Dimensions
21 calculators · 6 categories
CFD Calculators
Mesh sizing and wall treatment, turbulence model setup, time stepping and solution verification — the numbers a solver asks for before it will run, and the ones a reviewer asks for afterwards.
y+ to First Cell Height CalculatorTurn a target y+ into the first cell height you actually have to mesh — with the cell-centroid…Mesh & Wall TreatmentFirst Cell Height to y+ CalculatorYou have already built the mesh. This says what y+ it actually reaches, whether that suits the near-wall…Mesh & Wall TreatmentPrism Layer Stack CalculatorThe geometric series behind an inflation layer, done exactly: total thickness, last layer, the jump from the outermost…Mesh & Wall TreatmentTurbulence Inlet Conditions CalculatorTurbulence intensity, length scale, k, ε, ω and the eddy-viscosity ratio from one velocity and one length —…Turbulence & Time SteppingCourant Number (CFL) & Time Step CalculatorCFL from velocity, cell size and time step, and the time step a target CFL needs — judged…Turbulence & Time SteppingReynolds Number & Flow Regime CalculatorRe for a round pipe, a rectangular duct, an annulus, an open channel, a flat plate, a cylinder…Flow Regime & Dimensionless NumbersHydraulic Diameter CalculatorD_h = 4A/P for a round pipe, a rectangular or square duct, an annulus, parallel plates, a part-full…Internal Flow & Pressure DropPipe Friction Factor & Pressure Drop CalculatorDarcy friction factor, pressure drop, head loss, wall shear stress and pumping power for a pipe, duct or…Internal Flow & Pressure DropDarcy-Forchheimer Porous Media Coefficients CalculatorTurn a measured pressure-drop curve into the viscous and inertial resistance coefficients your solver asks for: a closed-form…Internal Flow & Pressure DropGrid Convergence Index (GCI) CalculatorThree grids, three solutions, and the number a reviewer asks for: the observed order of convergence, the Richardson-extrapolated…Verification & Solver Resources
35 calculators · 8 categories
Health Calculators
Infusion and drip rates, nutrition support, growth percentiles, pregnancy and the everyday numbers — for the bedside, the clinic, and for working something out about yourself.
IV Drip Rate Calculator (drops per minute)Drops per minute for a gravity infusion from the volume, the time and the giving set’s drop factor…Administration & InfusionInfusion Pump Rate Calculator (mL/h)The mL/h to set on the pump for a dose already prescribed in mcg/kg/min, mg/kg/h, units/kg/h or a…Administration & InfusionEnergy Requirement Calculator (Mifflin, Harris-Benedict, Schofield)What five published predictive equations yield in kcal/day for one set of inputs — Mifflin-St Jeor 1990, the…Nutrition SupportBMI Calculator (Standard and Asian-Indian Cut-offs)Body mass index from height and weight, in metric or imperial, printed to one decimal place and categorised…Weight & Body CompositionPregnancy Due Date & Gestational Age CalculatorGestational age in completed weeks and days, and an estimated due date, by four separately sourced dating methods…Pregnancy & ObstetricsDrug Reconstitution CalculatorA powder vial, the diluent you add and the displacement volume the manufacturer states, worked into the final…Administration & InfusionFluid Balance Chart CalculatorTotals a fluid balance chart over a shift or 24 hours: oral, intravenous, feed and flushes in; urine,…Administration & InfusionInfusion Time & Remaining Volume CalculatorHow much is left in the bag, how long it has to run, what time it will finish,…Administration & InfusionOxygen Cylinder Duration CalculatorHow long an oxygen cylinder will last at a given flow, worked from the gauge pressure and the…Administration & InfusionSyringe Driver Rate CalculatorA continuous subcutaneous infusion made up to a final volume and run over a set period, converted into…Administration & Infusion
12 calculators · 3 categories
Physics Calculators
Radioactive decay and activity, shielding and attenuation from NIST photon data, and dose rate — for the radiographer, the medical physicist and the radiation safety officer.
Half Value Layer and Transmission CalculatorThe half-value layer, the tenth-value layer and the transmission through any thickness, from NIST photon attenuation data for…Shielding & AttenuationGamma Dose Rate Point Source CalculatorThe dose rate from a point gamma source, with the air kerma rate constant printed as the published…Dose & Dose RateRadioactive Decay and Activity CalculatorThe activity left after an interval, the activity the interval implies going backward, and the time to reach…Radioactivity & DecayShield Thickness for a Target Dose Rate CalculatorThe thickness that takes a dose rate down to the figure you name — in millimetres, in half-value…Shielding & AttenuationDecay Correction to a Calibration Date CalculatorWhat a vial assayed for a stated calibration time holds now, what it will hold at administration, and…Radioactivity & DecayMass Attenuation Coefficient CalculatorNIST photon attenuation data as a reference: μ/ρ and μen/ρ for eight materials from 1 keV to 20…Shielding & AttenuationCT Dose: DLP to Effective Dose CalculatorEffective dose from the dose-length product, computed at three published coefficient sets at once — because for the…Dose & Dose RateFluoroscopy Skin Dose CalculatorPeak skin dose from the cumulative air kerma at the reference point, cross-checked against the kerma-area product route…Dose & Dose RateNuclear Medicine Administered Activity CalculatorAdministered activity scaled from a reference activity you supply, by eight methods side by side — because the…Dose & Dose RateHalf-Life, Decay Constant and Mean Life Calculatorλ = ln2/t½ and the mean life that is 1.4427 times the half-life rather than 0.6931 — with…Radioactivity & Decay
72 calculators · 7 categories
Sports Calculators
Scoring, rates and ratings, one category per sport, each with the governing body whose definition it follows and the season that definition belongs to.
Net Run Rate (NRR) CalculatorNet run rate as the ICC defines it: runs per over scored across the whole group, less runs…CricketLeague Table Points CalculatorTotal a team's league points in association football from its wins, draws and losses. The points per result…Football (Soccer)Elo Rating Change CalculatorExpected score and the new rating after one association football match, from two Elo ratings, a K value…Football (Soccer)Age-Graded Performance CalculatorThe age-factored performance World Masters Athletics defines: your time times the published age factor, rounded the way the…Athletics & RunningCombined Events Scoring CalculatorDecathlon and heptathlon points from the published closed form, not an interpolated table: A × (B − T)^C…Athletics & RunningPace Unit ConverterPace in one unit turned into pace in every other: seconds and minutes per kilometre, per mile, per…Athletics & RunningRace Split Times CalculatorA target pace turned into a finishing time, a per-kilometre split and a pair of halves — even,…Athletics & RunningRace Time Predictor CalculatorRiegel's endurance equation: a result at one distance turned into a predicted time at another, with the exponent…Athletics & RunningRunning Pace CalculatorPace per kilometre and per mile from a distance and a finishing time, with the speed beside it.…Athletics & RunningTrack Lane Distance and Stagger CalculatorThe exact length of one lap in any lane, and the stagger that makes a one-lap race fair,…Athletics & Running
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How these calculators are built
Each calculator is a page of arithmetic with its reasoning shown. The formula is printed, the worked example matches the figures the page opens with, and the references name the textbook, standard or manufacturer datasheet the numbers came from.
Nothing here is advice. A medical calculator does not know your patient, a financial one does not know your tax position, and an electronics one does not know your local wiring code. Use the result as a check on your own working, and take the decision with someone qualified to make it.