Engineering Calculators
Comprehensive calculators for electrical, power, cooling, hydraulic, mechanical, and civil engineering.
Professional Engineering Tools
Our engineering calculators cover six major disciplines: electrical and electronics, power systems, cooling and HVAC, hydraulic systems, mechanical engineering, and civil engineering. Each calculator includes detailed explanations of engineering principles, formulas, practical applications, and worked examples.
Whether you're designing circuits, sizing generators, analyzing cooling loads, calculating pipe flow, selecting bearings, or estimating concrete volumes, these tools help you perform accurate calculations and understand the underlying engineering concepts.
Electrical & Electronics (21)
Ohm's Law Calculator
Calculate voltage, current, resistance, or power using Ohm's Law
Use Calculator →Voltage Divider
Calculate output voltage in a voltage divider circuit
Use Calculator →Resistor Color Code
Decode resistor values from color bands or find colors for a value
Use Calculator →Capacitor Charge
Calculate capacitor charge time and energy
Use Calculator →Series & Parallel
Calculate equivalent resistance for series and parallel circuits
Use Calculator →Cable Size
Calculate appropriate cable size based on current and voltage drop
Use Calculator →Voltage Drop
Calculate voltage drop across wires and components for troubleshooting
Use Calculator →Current Divider
Calculate current distribution in parallel resistor circuits
Use Calculator →RC Time Constant
Calculate RC time constant and capacitor charge/discharge timing
Use Calculator →LED Resistor
Calculate the correct resistor value for LED circuits
Use Calculator →Battery Life
Calculate battery runtime based on capacity and load
Use Calculator →Power Dissipation
Calculate power dissipation in components for failure analysis
Use Calculator →Frequency Calculator
Calculate frequency, period, and LC resonant frequency
Use Calculator →Impedance Calculator
Calculate impedance and reactance for AC circuit analysis
Use Calculator →Wire Ampacity Calculator
Calculate wire current-carrying capacity based on gauge, insulation, and conditions
Use Calculator →Transformer Sizing
Calculate transformer kVA rating and sizing requirements
Use Calculator →Inductor Design
Calculate inductance, turns, and core parameters for inductor design
Use Calculator →Electrical Conduit Fill
Calculate conduit fill percentage and maximum conductors per NEC
Use Calculator →Grounding Calculator
Calculate grounding electrode resistance and ground rod requirements
Use Calculator →Arc Flash Calculator
Calculate incident energy and arc flash boundaries for safety
Use Calculator →Fault Current Calculator
Calculate three-phase short-circuit current per IEC 60909 / IEEE 141 for equipment ratings (NEC 110.9/110.10)
Use Calculator →Power Systems (7)
Power Calculator
Calculate electrical power from voltage and current
Use Calculator →3-Phase Power
Calculate 3-phase power, current, voltage, and power factor
Use Calculator →Diesel Generator Sizing
Calculate minimum size for a diesel standby generator for a given load
Use Calculator →Motor Load & Efficiency
Calculate motor power, efficiency, and energy consumption
Use Calculator →Peak Load Demand
Estimate peak electrical demand for cooling facilities
Use Calculator →Power Factor Correction
Calculate capacitor requirements and benefits
Use Calculator →Motor Starting Calculator
Calculate locked-rotor current (LRC), starting kVA, and voltage drop during motor starting per NEMA MG-1 / IEC 60034-12 / IEEE 141. Supports DOL, star-delta, autotransformer, soft starter, and VFD methods.
Use Calculator →Cooling & HVAC (27)
HVAC Basics
Beginner's guide to HVAC systems: refrigeration cycle, heating, ventilation, air distribution, and key metrics
Use Calculator →Cooling Load Calculator
Calculate cooling load (BTU/hr or kW) for buildings, rooms, equipment
Use Calculator →Heat Exchanger Sizing
LMTD method and effectiveness-NTU calculations
Use Calculator →Heat Transfer Calculators
Conduction, convection, and radiation heat transfer
Use Calculator →Pipe Heat Loss/Gain
Calculate heat loss or gain in pipes based on insulation and ambient conditions
Use Calculator →Solar Heat Gain
Calculate solar heat gain through windows and walls
Use Calculator →Cooling Capacity Converter
Convert between BTU/h, kW, tons, and watts
Use Calculator →CFM to Metric Converter
Convert between CFM and metric airflow units (m³/min, m³/h, L/s, L/min)
Use Calculator →Airflow vs Static Pressure
Calculate airflow characteristics, velocity, and fan power for ducts and fans
Use Calculator →Pressure Drop Calculator
Pressure drop in pipes, ducts and fittings (Darcy-Weisbach/CIBSE)
Use Calculator →Pump Sizing
Calculate pump power, head requirements, and NPSH
Use Calculator →Chilled Water/Brine Flow
Flow rate vs delta-T and cooling capacity calculations
Use Calculator →Refrigeration Cycle (CoP/EER)
Calculate Coefficient of Performance and Energy Efficiency Ratio
Use Calculator →Refrigerant Charge Estimator
Estimate refrigerant charge based on pipe runs and component volumes
Use Calculator →Superheat & Subcooling
Calculate superheat and subcooling for system diagnostics
Use Calculator →Compressor Capacity Correction
Correct compressor capacity for ambient temperature and elevation
Use Calculator →Psychrometric Calculator
Calculate humidity ratio, dew point, enthalpy, and more
Use Calculator →HVAC/CRAC/CRAH Setpoints
Understanding temperature and humidity control effects in HVAC systems
ASHRAE Humidity Calculator
Calculate dew point and verify conditions against ASHRAE TC 9.9 environmental classes
Use Calculator →Cooling Tower Approach & Range
Calculate approach, range, and effectiveness for evaporative cooling
Use Calculator →Blowdown Rate
Calculate blowdown rate vs cycles of concentration
Use Calculator →Drift Loss Estimation
Estimate drift loss for evaporative cooling systems
Use Calculator →Ventilation Requirements
Calculate ventilation requirements (ASHRAE-based)
Use Calculator →Refrigerant Pipe Sizing
Pipe sizing and max allowable charge for safety zones
Use Calculator →Boiler & Hydronic Sizing Calculator
Size a boiler from heat load, calculate design flow rate, pipe velocity, expansion tank volume, and radiator output correction per ASHRAE / CIBSE Guide B / EN 442.
Use Calculator →Ductwork Sizing Calculator
Size round and rectangular HVAC ducts using the equal friction method per ASHRAE Fundamentals Ch. 21 / SMACNA. Darcy-Weisbach friction with Colebrook-White, velocity limits, and rectangular equivalent diameter.
Use Calculator →NPSH Available Calculator
Net Positive Suction Head available per HI 9.6.1 and ISO 9906. Antoine equation for vapor pressure, cavitation risk assessment with HI recommended margin. Suction lift, flooded suction, and friction loss inputs.
Use Calculator →Hydraulic (8)
Pipe Flow Velocity
Calculate flow velocity in pipes based on flow rate and pipe diameter
Use Calculator →Reynolds Number
Calculate Reynolds number to determine flow regime (laminar, transitional, turbulent)
Use Calculator →Friction Factor
Calculate friction factor using Colebrook equation or Swamee-Jain approximation
Use Calculator →Pressure Drop (Darcy-Weisbach)
Calculate pressure drop in pipes using the Darcy-Weisbach equation
Use Calculator →Hydraulic Diameter
Calculate equivalent hydraulic diameter for non-circular conduits
Use Calculator →Hazen-Williams Flow
Calculate flow rate or head loss using the Hazen-Williams equation
Use Calculator →Orifice Flow
Calculate flow rate through an orifice plate or opening
Use Calculator →Water Hammer
Calculate water hammer pressure surge in pipelines
Use Calculator →Mechanical (9)
Bearing Life Calculator
Calculate L10 bearing life per ISO 281
Use Calculator →Gear Ratio Calculator
Multi-stage gear train speed and torque analysis
Use Calculator →Spring Design Calculator
Helical compression spring rate and stress
Use Calculator →Bolt Torque Calculator
Tightening torque for metric and imperial bolts
Use Calculator →Thermal Expansion Calculator
Linear thermal expansion for common materials
Use Calculator →Pressure Vessel Calculator
Wall thickness and stress per ASME BPVC
Use Calculator →Column Buckling Calculator
Critical buckling load using Euler (long columns) and Johnson parabolic (intermediate columns) formulas per AISC. Selects governing formula by slenderness ratio. Supports round, rectangular, hollow, and custom sections.
Use Calculator →Wind Load Calculator
Design wind pressures per ASCE 7-22 directional procedure. Velocity pressure qh, gust factor G, and net pressures for windward wall, leeward wall, sidewalls, and roof. Exposure categories B/C/D, risk categories I–IV.
Use Calculator →Fatigue Life Calculator
Modified Goodman and Gerber safety factors for fatigue loading per Shigley's Mechanical Engineering Design. Corrected endurance limit Se with Marin factors (surface finish, size, load type, reliability). S-N life estimate for finite-life region.
Use Calculator →Civil (5)
Beam Load Calculator
Reactions, moments, shear, and deflection analysis
Use Calculator →Concrete Calculator
Volume estimation for slabs, footings, walls, and columns
Use Calculator →Slope & Grade Calculator
Convert between percent grade, degrees, and ratio
Use Calculator →Stormwater Runoff Calculator
Rational method peak runoff estimation (Q=CiA)
Use Calculator →Soil Bearing Capacity
Terzaghi's bearing capacity for shallow foundations
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