multicalci.com
Standards-based Engineering Calculators · Free · Browser-based · No login
25
Tools
7
Disciplines
SI+US
Units
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📐 SI & Imperial
✅ Free Always
💰 BOQ Estimator NEW
⭐ Most-used calculators
⚗️Process & Fluid Systems8 tools
🎯Orifice Design & Sizing→
ISO 5167-2 orifice plate: Reader-Harris/Gallagher discharge coefficient, beta ratio, DP & permanent pressure loss.
ISO 5167RH/G CdDP Meter
🌀Pump, Compressor & Fan→
Centrifugal & PD pumps (NPSHA/NPSHR, affinity laws), multi-stage compressors with intercoolers, fans & blowers — isentropic & polytropic.
Pump/NPSHCompressorFan/BlowerAffinity Laws
🧪Gas Equation of State→
Real gas behaviour using Peng-Robinson, Soave-Redlich-Kwong & van der Waals EOS. Z-factor & compressibility calculations.
Peng-RobinsonSRKZ-Factor
🔄Engineering Units Converter→
30+ categories: pressure, flow, temperature, energy, power, viscosity, force & more. Full SI ↔ Imperial conversion.
SI ↔ Imperial30+ Categories
📉Pipe Pressure Drop Calculator→
Darcy-Weisbach & Hazen-Williams pipe friction losses. Colebrook-White friction factor, fittings, elevation head & multi-segment networks.
Darcy-WeisbachColebrook-WhiteFittings
🔧NPSH Calculator→
Net Positive Suction Head Available vs Required. Cavitation risk assessment, vapour pressure correction, suction line losses & pump selection guidance.
NPSHACavitationSuction Head
📐Head & Pressure Calculator→
Static, dynamic & total head calculations. Pump head, system curve, fluid column pressure for any fluid density & elevation difference.
Static HeadSystem CurvePump Head
🌡️Heat Transfer & Thermodynamics7 tools
♨️Heat Exchanger Design→
Shell & tube (TEMA classifications), Bell-Delaware shell-side, LMTD correction factor, overall U-value & fouling resistance.
TEMABell-DelawareLMTD
💨Steam Properties (IAPWS-IF97)→
Full steam tables per IAPWS-IF97. Saturated & superheated steam properties, wet quality, enthalpy, entropy & specific volume.
IAPWS-IF97SaturationSuperheat
⚡Steam Turbine Power→
Isentropic efficiency, power output & steam consumption for condensing & back-pressure turbines. Rankine cycle analysis.
IsentropicRankine CycleBack-Pressure
❄️Steam Quench Calculator→
Desuperheater & steam quench calculations. Spray water flow rate, outlet temperature & enthalpy balance for steam conditioning.
DesuperheaterSpray WaterEnthalpy
🔁Rankine Cycle Calculator→
Ideal & actual Rankine cycle analysis. Thermal efficiency, boiler heat input, turbine & pump work, condenser heat rejection.
Thermal EfficiencyBoilerCondenser
🌬️Psychrometric Calculator→
Moist air: dew point, wet-bulb, humidity ratio, specific enthalpy & volume for HVAC & drying system design.
Dew PointWet BulbHVAC
🏭Cooling Tower Performance→
CTI ATC-105 thermal performance: NTU-Merkel method, approach & range, tower characteristic, drift & evaporation losses.
CTI ATC-105NTU-MerkelApproach/Range
🛢️Vessels, Separators & Materials4 tools
🛢️Vessel / Separator Sizing→
Horizontal & vertical separators: retention time, mist eliminator, nozzle sizing per ASME VIII & API 12J.
ASME VIIIAPI 12JSeparator
🔬Material of Construction→
Corrosion resistance guide for pipes & equipment. Select optimal material by fluid chemistry, temperature & concentration.
Corrosion GuideAlloysPiping
📚Material Grades Library→
Comprehensive material grades reference: ASTM, DIN, EN & ISO standards for steels, alloys & non-ferrous materials.
ASTMDIN/ENSteel Grades
💧Water Treatment Calculator→
Chemical dosing, blowdown rates, cycles of concentration for boiler & cooling tower water treatment systems.
Chemical DosingBlowdownBoiler Water
💰 Capital Cost Estimating 1 tool
💰 BOQ Capital Cost Estimator →
Professional AACE Class 4 process plant capital cost estimator. 214 equipment types across 5 disciplines, power-law Turton correlations with CEPCI escalation, location factors for 19 countries, P/T correction, discipline-weighted indirect costs, sensitivity analysis, WBS tagging, system view, offline mode and Quote List CSV export.
AACE Class 4 214 Equipment Items 19 Countries Turton Correlations CEPCI Escalation Sensitivity Analysis Offline PWA
Engineering suites
🏗️CivilCalc Pro→
Beam bending, column, concrete mix, pipe flow (Manning/H-W), retaining wall, earthwork & surveying.
StructuralHydraulicsGeotechnical
⚡ElecCalc Pro→
Ohm's law, AC/DC power, cable sizing (IEC 60228), motor, transformer, fault current (IEC 60909) & HV testing.
Cable SizingMotorIEC 60909
📡InstruCalc Pro→
4–20 mA signal conversion, square root extractor (DP flow), loop integrity, thermowell (ASME PTC 19.3) & thermocouple reference.
4-20mAThermowellASME PTC 19.3
⚙️MechCalc Pro→
Structural, beam, ASME VIII vessel, bolt & flange, AWS D1.1 weld, AGMA gear, shaft, spring, fastener & CNC machining.
ASME VIIIAWS D1.1AGMA
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Complete Engineering Calculators Directory

Browse all free engineering calculators including process, heat transfer, civil, electrical, mechanical and instrumentation tools.

Process & Fluid Systems

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Vessels & Materials

Engineering Suites

Frequently Asked Questions

Is there a capital cost estimating tool?

Yes — the BOQ Capital Cost Estimator is a free, browser-based AACE Class 4 estimating tool covering 214 equipment types across Process, Mechanical, Civil, Electrical and Instrumentation disciplines. It uses Turton power-law correlations with CEPCI escalation, location factors for 19 countries, P/T correction, discipline-weighted indirect costs, sensitivity analysis, WBS tagging, offline mode and downloadable Quote List CSV export. No login required.

Are the calculators free to use?

Yes — all calculators are completely free, run in your browser and require no login, registration or subscription. They work on any device with a modern browser.

Which engineering standards are implemented?

ISO 5167 (orifice/flow), IEC 60534 (control valves), IAPWS-IF97 (steam properties), TEMA E/F/G/H/J/X (heat exchangers), ASME B31.3/VIII (piping/vessels), CTI ATC-105 (cooling towers), Darcy-Weisbach + Colebrook-White (pipe flow), ASME PTC 19.3 (thermowell analysis), API 12J (separators), Peng-Robinson & SRK EOS (gas properties).

Do calculators support both SI and Imperial units?

Yes. All process and fluid calculators support one-click switching between SI (metric) and US Customary (Imperial) unit systems. Results update instantly without re-entering data.

Can results be used for final engineering designs?

These calculators are suitable for preliminary engineering, feasibility studies, educational use and cross-checking. All results must be independently verified by a qualified registered engineer against applicable codes and standards before use in final designs.