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Students' toolkit
Fast, formula-first tools for assignments, labs and viva prep.
Professionals' toolkit
Standards-based calculators for design checks, estimation and field decisions.
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Filter by discipline or search by what you are trying to work out. Every tool is live and free.
Cable Size Calculator
Size conductors from load current using ampacity, derating factors and voltage-drop limits.
Open tool : Cable Size CalculatorHome Load Calculator
Add up household appliances, then size your inverter, battery bank and rooftop solar.
Open tool : Home Load CalculatorTransformer Calculator
Full-load current, short-circuit current, regulation and parallel-operation checks for any kVA.
Open tool : Transformer CalculatorVoltage Drop Calculator
Check DC, single-phase and three-phase drop against the usual 3% and 5% limits.
Open tool : Voltage Drop CalculatorRelay Coordination Tool
Plot IEC 60255 IDMT curves, verify CTI margins and grade overcurrent relays.
Open tool : Relay Coordination ToolElectrical Symbol Finder
Search 60+ IEC circuit symbols by name or function and download each one as SVG.
Open tool : Electrical Symbol FinderTransformer Sizing Calculator
Size the feeding transformer for motor and mixed loads with starting inrush and margins.
Open tool : Transformer Sizing CalculatorOhm's Law Calculator
Solve voltage, current, resistance and power from any two known values instantly.
Open tool : Ohm's Law CalculatorResistor / Capacitor / Inductor Color Code Calculator
Decode 4, 5 and 6-band resistors plus capacitor and inductor codes, with tolerance.
Open tool : Resistor / Capacitor / Inductor Color Code CalculatorAntenna Length Calculator
Size dipole, monopole, ground-plane and Yagi elements for any frequency and velocity factor.
Open tool : Antenna Length CalculatorLogic Gate Truth Table Generator
Build truth tables, simplify Boolean expressions and read Karnaugh maps for four variables.
Open tool : Logic Gate Truth Table GeneratorOp-Amp Gain / Filter Designer
Design inverting, non-inverting and active filter stages with GBW and slew-rate checks.
Open tool : Op-Amp Gain / Filter DesignerPCB Trace Width Calculator
IPC-2221 trace width, temperature rise, resistance and via current capacity.
Open tool : PCB Trace Width CalculatorSubnet Calculator (CIDR)
Network address, broadcast, usable host range and mask conversion for any IPv4 CIDR block.
Open tool : Subnet Calculator (CIDR)IP Address Class Finder
Identify class A to E, default mask, and whether an address is private or reserved.
Open tool : IP Address Class FinderNumber Base Converter
Convert between binary, octal, decimal, hexadecimal and any custom base instantly.
Open tool : Number Base ConverterPassword Strength Checker
Estimate entropy and crack time, and see exactly which rules a password passes or fails.
Open tool : Password Strength CheckerRegex Tester & Builder
Test patterns against sample text offline, with match highlighting and a plain breakdown.
Open tool : Regex Tester & BuilderBig-O Complexity Estimator
Compare growth rates and estimate operation counts for common algorithms at any size.
Open tool : Big-O Complexity EstimatorGear Ratio Calculator
Up to five gear stages with idlers, efficiency losses, output torque and an SVG diagram.
Open tool : Gear Ratio CalculatorBelt & Pulley Speed Calculator
Driven speed, belt length, wrap angle and slip check for open and crossed belt drives.
Open tool : Belt & Pulley Speed CalculatorShaft Diameter Calculator
Size solid or hollow shafts under combined torque and bending, with angle-of-twist check.
Open tool : Shaft Diameter CalculatorSpring Design Calculator
Spring rate, Wahl-corrected stress, solid height and surge frequency for helical springs.
Open tool : Spring Design CalculatorBearing Life (L10) Calculator
ISO 281 rating life in revolutions, hours and years from load rating and speed.
Open tool : Bearing Life (L10) CalculatorConcrete Mix Design Calculator
IS 10262 mix design for M20 to M40 with cement, sand and aggregate quantities.
Open tool : Concrete Mix Design CalculatorBar Bending Schedule Generator
IS 2502 cutting lengths, bend deductions, hook allowances and total steel weight.
Open tool : Bar Bending Schedule GeneratorBeam Deflection Calculator
Point load and UDL deflection with a span/250 check and live bending and shear diagrams.
Open tool : Beam Deflection CalculatorColumn Design Load Calculator
IS 456 axial capacity, slenderness classification and reverse sizing for short columns.
Open tool : Column Design Load CalculatorBrick / Block Quantity Estimator
Bricks, cement bags, sand volume and total wall cost from your wall dimensions.
Open tool : Brick / Block Quantity EstimatorChemical Dilution Calculator
Solve C1V1 = C2V2 for any unknown and get the exact stock and diluent volumes.
Open tool : Chemical Dilution CalculatorMolarity / Normality Calculator
Convert between mass, moles, molarity and normality for any solute and volume.
Open tool : Molarity / Normality CalculatorReynolds Number Calculator
Classify pipe flow as laminar, transitional or turbulent from velocity and viscosity.
Open tool : Reynolds Number CalculatorpH Calculator (Acid-Base)
Find pH, pOH and hydrogen ion concentration for strong and weak acids and bases.
Open tool : pH Calculator (Acid-Base)Distillation Column Basic Sizing
McCabe-Thiele lite: minimum reflux, theoretical stages and first-pass column height.
Open tool : Distillation Column Basic SizingLift & Drag Coefficient Calculator
Derive Cl and Cd from lift, drag, wing area and dynamic pressure, then read L/D.
Open tool : Lift & Drag Coefficient CalculatorRocket Equation (Tsiolkovsky) Calculator
Tsiolkovsky delta-v from mass ratio and specific impulse, with propellant breakdown.
Open tool : Rocket Equation (Tsiolkovsky) CalculatorMach Number Calculator
Mach number and flow regime from true airspeed, altitude and local speed of sound.
Open tool : Mach Number CalculatorWing Loading Calculator
Wing loading, stall speed and thrust-to-weight for fixed-wing aircraft and UAV designs.
Open tool : Wing Loading CalculatorOrbital Velocity Calculator
Circular orbital velocity, period and escape velocity for any altitude around any body.
Open tool : Orbital Velocity CalculatorEV Battery Range Estimator
Estimate real-world range from pack capacity, consumption, payload and driving style.
Open tool : EV Battery Range EstimatorFuel Efficiency (Mileage) Calculator
Convert between kmpl, mpg and L/100 km, and work out trip fuel cost from distance.
Open tool : Fuel Efficiency (Mileage) CalculatorEngine Power / Torque Converter
Convert HP, kW, BHP and Nm at any engine speed, with a torque-power relationship view.
Open tool : Engine Power / Torque ConverterBraking Distance Calculator
Reaction plus braking distance from speed, friction, road grade and reaction time.
Open tool : Braking Distance CalculatorEV Charging Time Estimator
Charging duration from pack size, state of charge, charger power and efficiency.
Open tool : EV Charging Time EstimatorOEE Calculator
Overall equipment effectiveness from availability, performance and quality, with benchmarks.
Open tool : OEE CalculatorEconomic Order Quantity (EOQ) Calculator
Optimal order size, reorder point and total inventory cost from demand and cost inputs.
Open tool : Economic Order Quantity (EOQ) CalculatorLine Balancing Efficiency Calculator
Cycle time, minimum stations, balance delay and line efficiency for assembly lines.
Open tool : Line Balancing Efficiency CalculatorInventory Carrying Cost Estimator
Annual carrying cost as a percentage of inventory value, split by each cost driver.
Open tool : Inventory Carrying Cost EstimatorMachine Cycle Time Estimator
Cycle time, throughput per shift and takt comparison from setup, run and handling times.
Open tool : Machine Cycle Time EstimatorPID Controller Tuning Estimator
Ziegler-Nichols and Cohen-Coon gains from step response or ultimate gain and period.
Open tool : PID Controller Tuning EstimatorSensor Range / Accuracy Converter (4-20 mA)
Convert between 4-20 mA, 0-10 V and engineering units, with the error band at any point.
Open tool : Sensor Range / Accuracy Converter (4-20 mA)Control Valve Cv Sizing Calculator
Flow coefficient Cv and Kv for liquid service, with choked-flow and pressure-drop checks.
Open tool : Control Valve Cv Sizing CalculatorInstrument Air Consumption Estimator
Total plant instrument-air demand from valve and positioner counts and duty cycle.
Open tool : Instrument Air Consumption EstimatorSignal Loop Wiring Calculator
Loop resistance budget, maximum cable length and compliance voltage for a 4-20 mA loop.
Open tool : Signal Loop Wiring CalculatorCarbon Footprint Calculator
Annual CO2 footprint from electricity, fuel, travel and waste in one place.
Open tool : Carbon Footprint CalculatorRainwater Harvesting Tank Size Calculator
Size a storage tank from roof catchment area, local rainfall and daily demand.
Open tool : Rainwater Harvesting Tank Size CalculatorWater Treatment Dosing Calculator
Coagulant, chlorine and lime dose plus daily chemical demand for a treatment plant.
Open tool : Water Treatment Dosing CalculatorBOD / COD Estimator
Estimate BOD, COD and their ratio to gauge how biodegradable a wastewater is.
Open tool : BOD / COD EstimatorSolid Waste Generation Estimator
Daily and annual municipal solid-waste load from population and per-capita rate.
Open tool : Solid Waste Generation EstimatorBlast Hole Pattern Calculator
Burden, spacing, powder factor and charge per hole for a surface blast pattern.
Open tool : Blast Hole Pattern CalculatorDrilling Mud Weight Calculator
Mud weight, hydrostatic pressure and equivalent circulating density for a well.
Open tool : Drilling Mud Weight CalculatorOre Grade / Tonnage Estimator
Contained metal and recoverable tonnage from ore grade, volume and recovery rate.
Open tool : Ore Grade / Tonnage EstimatorReservoir Volume Estimator (OOIP)
Original oil in place from area, net pay thickness, porosity and water saturation.
Open tool : Reservoir Volume Estimator (OOIP)Wellhead Pressure Converter
Convert wellhead pressure across psi, bar, kPa and mud-weight gradient.
Open tool : Wellhead Pressure ConverterBMI + Medical Dosage Unit Converter
Body mass index, body surface area and weight-based dosage for clinical calculations.
Open tool : BMI + Medical Dosage Unit ConverterDNA / RNA Codon Translator
Translate DNA or RNA sequences into amino acids with reading-frame options.
Open tool : DNA / RNA Codon TranslatorECG Signal Sampling Rate Calculator
Nyquist-safe sampling rate, storage size and aliasing check for ECG and biosignals.
Open tool : ECG Signal Sampling Rate CalculatorIrrigation Water Requirement Calculator
Crop water requirement from evapotranspiration, crop coefficient, rainfall and efficiency.
Open tool : Irrigation Water Requirement CalculatorCrop Yield Estimator
Expected yield per hectare from plant density, grains per head and grain weight.
Open tool : Crop Yield EstimatorTractor / Farm Machinery Power Calculator
Tractor drawbar power, PTO requirement and implement matching from draft and speed.
Open tool : Tractor / Farm Machinery Power CalculatorSolar / Wind Hybrid System Sizing Tool
Size a solar-plus-wind hybrid with battery backup from your daily load and site resource.
Open tool : Solar / Wind Hybrid System Sizing ToolCarbon Credit Estimator for Renewable Projects
Estimate annual carbon credits and revenue from a solar, wind or biomass project's output.
Open tool : Carbon Credit Estimator for Renewable ProjectsShip Stability (Metacentric Height) Calculator
Metacentric height, righting lever and initial stability from KB, BM and KG values.
Open tool : Ship Stability (Metacentric Height) CalculatorPropeller Pitch Calculator
Theoretical speed, slip and pitch selection from engine RPM, gear ratio and diameter.
Open tool : Propeller Pitch CalculatorScientific Calculator
Full scientific calculator with trig, logs, powers, memory and radian or degree modes.
Open tool : Scientific CalculatorPercentage Calculator
Percentage of a number, percentage change and reverse-percentage, all in one place.
Open tool : Percentage CalculatorEngineering Unit Calculator
Convert across length, mass, pressure, power, flow and dozens more unit families.
Open tool : Engineering Unit CalculatorPower Calculator
Raise numbers to any power, take roots and read scientific-notation results instantly.
Open tool : Power CalculatorNo tool matches that yet
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Each module ships with the real formula, checked against worked examples.
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Results follow IS, IEC, ISO and IPC references wherever a standard applies.
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