Engineering Calculators
51 deterministic calculators for structural, mechanical, electrical, and chemical engineering. Each tool runs against the engineering reference database.
Aerospace
Compressible Flow Calculator
Calculates isentropic, normal shock, Fanno, and Rayleigh flow properties for a given Mach number and specific-heat ratio. Provides both analytical results and table interpolation for cross-verification. Optionally computes ISA atmospheric conditions at a given altitude.
Free with sign-inNACA Airfoil Lookup
Looks up NACA airfoil aerodynamic coefficients (Cl, Cd, Cm) at a given angle of attack via interpolation. Optionally computes lift, drag, L/D ratio, and Reynolds number for a finite wing given span, chord, velocity, and altitude.
Paid tier
Chemical
Civil
Anchor Bolt Design
Checks cast-in-place and post-installed anchor bolt capacity per ACI 318-19 Chapter 17. Evaluates steel tension, concrete breakout tension, steel shear, concrete breakout shear, and tri-linear tension-shear interaction. Supports cracked/uncracked concrete and seismic conditions.
Free with sign-inBearing Capacity
Calculates ultimate and allowable bearing capacity for shallow foundations using Terzaghi, Meyerhof, Hansen, or Vesic methods. Looks up bearing capacity factors (Nc, Nq, Nγ) from reference tables and applies shape, depth, and water table corrections.
Free with sign-inBolt Connection Design (AISC)
Designs and checks bolted connections per AISC 360 J3. Calculates bolt shear, tension, and combined capacity for single bolts and bolt groups. Supports A325, A490, SAE, and ISO bolt grades.
Free to useConcrete Beam Design Check (ACI)
Checks a reinforced concrete beam for flexural capacity, shear capacity, and reinforcement limits per ACI 318-19. Looks up rebar areas from reference tables and applies phi factors for strength reduction.
Free to useMasonry Wall Design Check (TMS 402)
Checks a masonry bearing wall for axial and flexural capacity using Allowable Stress Design (ASD) per TMS 402. Looks up masonry unit properties from reference tables, computes slenderness ratio, axial stress, bending stress from lateral load, and unity check.
Free with sign-inPile Foundation
Calculates ultimate and allowable axial capacity of driven piles using static analysis methods. Uses alpha method for clay (total stress) and beta method for sand (effective stress). Looks up pile section properties and bearing capacity factors from reference tables.
Free with sign-inRetaining Wall Stability
Checks stability of gravity and cantilever retaining walls. Calculates Rankine active/passive earth pressures, overturning and sliding factors of safety, bearing pressure, and eccentricity. Looks up soil properties and code-minimum safety factors from reference tables.
Free with sign-inSteel Beam Design Check (AISC)
Checks a steel W-shape beam for flexural capacity, shear capacity, and deflection per AISC 360-22. Looks up section properties from the AISC shapes table and evaluates compactness, lateral-torsional buckling, and demand/capacity ratios.
Free to useSteel Column Design Check (AISC)
Checks a steel W-shape column for axial compressive capacity per AISC 360-22 Chapter E. Looks up section properties from the AISC shapes table, calculates Euler buckling stress, critical stress (inelastic or elastic), nominal and design compressive strength, demand/capacity ratio, and element slenderness classification per Table B4.1a.
Free with sign-inStormwater & Open Channel
Calculates stormwater peak runoff using the Rational Method (Q = CiA) and open-channel flow using Manning's Equation. Supports circular (full and partial), rectangular, and trapezoidal channel shapes. Computes flow rate, velocity, Froude number, and flow regime. Looks up Manning's n and runoff coefficients from reference tables.
Paid tierWastewater Treatment Design
Sizes an activated sludge wastewater treatment system. Calculates aeration tank volume, hydraulic retention time, F/M ratio, sludge production, oxygen and air requirements, and secondary clarifier area. Uses biokinetic constants from reference tables and validates results against standard design parameter ranges.
Paid tierWood Beam Design Check (NDS)
Checks a sawn lumber beam for bending, shear, and deflection per NDS (National Design Specification). Looks up reference design values from the NDS timber table, applies adjustment factors (CD, CM, Ct, CL, CF, Cr), and evaluates demand/capacity ratios.
Free to use
Electrical
Battery DC System Sizing Calculator
Sizes stationary battery banks for substation and datacenter DC systems per IEEE 485. Determines number of cells, required capacity with temperature and aging corrections, selects a battery model from the reference table, calculates string voltage range, and sizes the battery charger.
Paid tierBusway Voltage Drop Calculator
Calculates voltage drop for busway/busduct installations per NEC 210.19 limits. Looks up manufacturer-specific R and X from the busway-specs table and applies distribution pattern factors for end-fed, center-fed, or uniformly distributed loads.
Free with sign-inDry-Type Transformer Sizing
Selects the next-size-up dry-type transformer for a given load and calculates partial-load losses, efficiency, heat output, secondary full-load amps, available fault current, and voltage regulation.
Free to useGenerator Sizing & Fuel Calculator
Sizes standby or prime diesel generators for a facility load with N/N+1/2N redundancy, altitude and temperature derating per NEMA MG1, fuel storage sizing per NFPA 110 (Level 1 / Level 2), and motor starting kVA verification.
Paid tierMotor Branch Circuit Sizing (NEC 430)
Sizes motor branch circuit components per NEC Article 430: conductor ampacity (430.22), overcurrent protection (430.52), overload relay settings (430.32), and feeder sizing for multiple motors (430.24/430.62).
Paid tierMotor Sizing & Electrical Specification
Looks up motor full-load current (NEC 430), efficiency, power factor, torque characteristics, and starting current for a given motor HP and voltage. Returns FLC at all standard voltages, locked-rotor current, and NEMA performance data.
Free to useNEC Cable Sizing & Voltage Drop
Sizes electrical conductors per NEC ampacity tables with ambient temperature and conduit fill derating. Calculates voltage drop, selects conduit size, and determines grounding conductor size.
Fire_protection
Clean Agent Fire Suppression Sizing
Sizes clean-agent fire suppression systems (FM-200, Novec 1230, IG-541, CO2) per NFPA 2001. Calculates agent quantity, cylinder count, design concentration, hold time, and discharge time.
Paid tierFire Sprinkler Hydraulic Calculator
Calculates fire sprinkler system hydraulic demand per NFPA 13. Determines design density, flow per sprinkler, pressure at the most remote head, pipe friction losses via Hazen-Williams, total system demand, and water supply adequacy.
Paid tier
Manufacturing
ISO 286 Fits & Tolerances
Calculates hole and shaft limits, clearance or interference, and tolerance zones for standard ISO 286 metric fits. Covers clearance, transition, and interference fits for hole-basis system.
Free with sign-inMachining Speeds, Feeds & Cycle Time
Calculates RPM, feed rate, material removal rate, cycle time, cutting power, and surface finish for turning, milling, and drilling operations. Looks up recommended speeds and feeds from reference data by operation, workpiece material, and tool type.
Paid tier
Mechanical
Boiler Selection & Efficiency Calculator
Selects a boiler for a given heating load and calculates fuel input rate, annual operating cost, altitude derating, and redundancy configuration. Supports condensing gas, electric resistance, firetube (gas/oil), and watertube (gas/oil) boiler types.
Free with sign-inCooling Tower Selection & Sizing
Sizes cooling towers for datacenter or HVAC condenser water systems. Calculates water balance (evaporation, blowdown, drift, makeup), determines number of cells, fan power, and Merkel number (KaV/L) using the Chebyshev four-point approximation.
Paid tierDatacenter Cooling Unit Selection
Selects cooling units for datacenter IT loads. Looks up ASHRAE thermal guidelines for the specified class, calculates required airflow, selects units from the cooling-specs table by cooling type and sensible capacity, applies redundancy, and computes partial PUE contribution from cooling.
Paid tierHeat Exchanger Sizing
Sizes a heat exchanger using LMTD or NTU-effectiveness method. Pulls fluid properties (cp, density, viscosity) from reference tables at operating temperatures. Estimates overall U from Perry's Table 11-3 fluid-pair data and fouling factors from TEMA RGP-T-2.
Free to useHelical Compression Spring Design
Designs and analyzes helical compression springs. Calculates spring rate, stress, safety factor, solid length, natural frequency, and buckling risk. Looks up wire material properties for allowable stress.
Free with sign-inHVAC Cooling Load Estimation
Estimates building cooling loads using a simplified ASHRAE method. Calculates envelope conduction (walls, windows, roof), solar gain, internal loads (people, lighting, equipment), and ventilation loads. Returns sensible/latent breakdown, total tonnage, and SHR.
Free with sign-inHVAC Duct Sizing Calculator
Sizes round and rectangular HVAC ducts using equal friction, velocity reduction, or static regain methods. Calculates friction and fitting losses, total pressure drop, and flags noise concerns. Looks up fitting loss coefficients from ASHRAE reference data.