GAS Calculators
4 calculators
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Gas Appliance Room Ventilation & Combustion Air Calculator
Free gas room ventilation calculator. Work out combustion and ventilation air for a boiler...
📐 NFPA 54 / ASHRAE
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PNG (Piped Natural Gas) Pipe Sizing Calculator
Free PNG pipe sizing calculator. Size low-pressure piped natural gas pipe diameter from ga...
📐 PNGRB / NFPA 54
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Gas Pressure Regulator Sizing Calculator (Cv)
Free gas pressure regulator sizing calculator. Find the required valve flow coefficient (C...
📐 NFPA 58 / IGC
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LPG Cylinder Bank Sizing Calculator
Calculate LPG cylinder bank size for commercial kitchens, hotels and industrial use. Consu...
📐 NFPA 54 / IGC
HVAC Calculators
30 calculators
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Room Sensible Heat Ratio (SHR / RSHF) Calculator
Free sensible heat ratio calculator. Find the room SHR from sensible and latent cooling lo...
📐 ASHRAE Fundamentals
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HVAC System BOQ & Budget Estimator (Concept Stage)
Free HVAC BOQ estimator. Order-of-magnitude bill of quantities and cost for chillers, AHUs...
📐 Order-of-magnitude estimate
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HVAC Energy Efficiency Calculator (COP, EER, Annual Cost)
Free HVAC efficiency calculator. Find chiller/AC COP and EER from cooling capacity and inp...
📐 AHRI 550/590 / ASHRAE 90.1
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Boiler Feed Pump Sizing Calculator (Flow, Head & Motor Power)
Free boiler feed pump sizing calculator: feed water flow, total pump head and shaft/motor ...
📐 Spirax Sarco / IBR
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HVAC Delta T Calculator (ΔT, Heat Transfer & Flow)
Free HVAC delta T calculator: find temperature difference (ΔT = T1 − T2) and the heat t...
📐 ASHRAE
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Duct Size Calculator (Online Ductulator): HVAC Ductwork Sizing
Free online ductulator and duct sizer: round and rectangular duct sizes from CFM or L/s, f...
📐 SMACNA / ASHRAE
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Heat Load Calculator: HVAC Cooling Load & AC Tonnage (CLTD)
Free heat load calculator: room cooling load and AC tonnage (TR) by the ASHRAE CLTD method...
📐 ASHRAE
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Pump Head Calculator: Total Dynamic Head (TDH) & Pump Power
Free pump head calculator: total dynamic head (TDH), friction loss and pump power by Darcy...
📐 HI
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Chiller Tonnage Calculator: Chiller Sizing & TR Calculation (BTU)
Free chiller tonnage calculator: convert cooling load in kW or BTU/h to tons of refrigerat...
📐 ASHRAE / AHRI
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Air Handling Unit (AHU) Sizing Calculator
Size AHU airflow, cooling coil, fan kW and chilled water flow from cooling load. ASHRAE 62...
📐 ASHRAE 62.1 / ASHRAE
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Psychrometric Calculator (Wet Bulb, Dew Point, Enthalpy)
Calculate wet bulb temperature, dew point, humidity ratio, enthalpy and specific volume fr...
📐 ASHRAE Fundamentals
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Duct Pressure Drop Calculator: Air Duct Friction Loss (Pa/m)
Free duct pressure drop calculator: friction loss per metre or 100 ft, velocity pressure a...
📐 ASHRAE Handbook / ISHRAE
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Smoke Exhaust Calculator
Design smoke exhaust and smoke control systems for buildings. Calculate smoke exhaust airf...
📐 ASHRAE / NFPA 92
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Fresh Air Ventilation Calculator
Calculate minimum fresh air supply rates for buildings to meet indoor air quality requirem...
📐 ASHRAE 62.1 / ASHRAE
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Chilled Water Pipe Sizing Calculator
Size chilled water pipes for central HVAC systems. Calculate pipe diameter, pressure drop,...
📐 ASHRAE Handbook / ISHRAE
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Cooling Tower Sizing Calculator: Condenser Water Flow, Range & Approach
Free cooling tower sizing calculator: condenser water flow, range and approach for chiller...
📐 CTI ATC-105 / ASHRAE
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Free Refrigerant Line Sizing Calculator (VRF & Split AC)
Size liquid and suction refrigerant lines for VRF and split AC systems. Supports R32, R410...
📐 ASHRAE / JIS B8607
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Free Condensate Drain Pipe Sizing Calculator (ASHRAE / IMC)
Size AHU and FCU condensate drain pipes from cooling capacity. Condensate flow rate, drain...
📐 ASHRAE / IMC 307
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Free AHU Condensate Drain Trap Calculator (P-Trap Depth)
Calculate AHU condensate P-trap seal and total depth from fan static pressure. Draw-throug...
📐 ASHRAE / SMACNA
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Free Server Rack Heat Load Calculator (ASHRAE TC 9.9)
Calculate server room and data centre cooling load from rack power. Heat in kW, tonnage an...
📐 ASHRAE TC 9.9
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Free Online Expansion Tank Sizing Calculator
Size a diaphragm or bladder expansion tank for closed heating and chilled-water loops. Use...
📐 ASHRAE
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Free Online Diffuser & Grille Sizing Calculator
Size supply diffusers and return grilles from airflow and face velocity, with a built-in n...
📐 ASHRAE
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Free Online Kitchen Exhaust Hood Airflow Calculator
Calculate commercial kitchen hood exhaust CFM and make-up air from hood length, cooking du...
📐 NFPA 96
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Free Online Fan Power Calculator
Calculate fan brake power (BHP/kW) and specific fan power from airflow and static pressure...
📐 AMCA / ASHRAE 90.1
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Free Online VAV Box Sizing Calculator
Size a VAV box from the zone cooling load: maximum and minimum CFM, inlet size and selecti...
📐 ASHRAE / SMACNA
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Free Online Cooling Coil Selection Calculator
Size an AHU cooling coil: face area, face velocity, number of rows and chilled-water flow ...
📐 ASHRAE / AHRI 410
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Free Online Cold Room Load Calculator
Calculate cold room / cold store refrigeration load - transmission, product, infiltration ...
📐 ASHRAE Refrigeration
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Free Online Humidification Load Calculator
Calculate humidification capacity (kg/h) for an AHU or space from airflow and humidity rat...
📐 ASHRAE Fundamentals
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Free Online Energy Recovery Wheel Calculator
Calculate sensible and total energy recovered by a heat recovery wheel (HRW/ERV) from airf...
📐 ASHRAE 90.1
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Free Online Pipe & Duct Insulation Thickness Calculator
Calculate minimum insulation thickness for pipes and ducts to control heat gain/loss and p...
📐 ASTM C / ASHRAE 90.1
MECH Calculators
19 calculators
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Slab / Floor Equipment Load Calculator (UDL Check)
Free slab equipment load calculator. Convert equipment weight and base area into a distrib...
📐 ASCE 7
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Pipe & Cable Burial Depth (Trench) Calculator
Free pipe and cable burial depth calculator. Find the minimum cover and trench width and d...
📐 IS 1255 / NEC 300.5
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Vibration Isolation Calculator (Isolator Static Deflection)
Free vibration isolation calculator. Find the required isolator static deflection and load...
📐 ASHRAE / ACI 351
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MEP Cost Estimator (Concept Budget)
Free MEP cost estimator. Get an order-of-magnitude combined mechanical, electrical and plu...
📐 Order-of-magnitude estimate
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Equipment Inertia Base (Concrete Pad) Calculator
Free inertia base calculator for pumps, fans and AHUs. Size the concrete inertia pad mass ...
📐 ASHRAE / ACI 351
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Rooftop Equipment Roof Load Calculator (ASCE 7 / IS 875)
Free rooftop equipment roof load calculator. Check if the roof slab can carry an AHU, chil...
📐 ASCE 7 / IS 875
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Free Online NPSH & Suction Lift Calculator
Calculate NPSH available to prevent pump cavitation from suction lift, friction, temperatu...
📐 HI / Hydraulic Institute
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Free Online Steam Pipe Sizing Calculator
Size steam pipes from steam flow, pressure and velocity limit. Free steam pipe sizing calc...
📐 CTI / ASME B31.1
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Free Online Steam Trap Selection Calculator
Select and size a steam trap from condensate load, pressure and application. ASME basis. F...
📐 ASHRAE / ASME
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Free Online Pump Affinity Laws Calculator
Predict pump flow, head and power at a new speed or impeller diameter using the affinity l...
📐 HI / Hydraulic Institute
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Free Online Cable Tray Support Span Calculator
Calculate the maximum support span for a loaded cable tray from cable load and tray class....
📐 NEC / NEMA VE-1
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Reynolds Number Calculator - Pipe Flow Regime (Laminar / Turbulent)
Free Reynolds number calculator. Enter velocity, pipe diameter and fluid to find Re and wh...
📐 Fluid Mechanics / Moody
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Simply Supported Beam Calculator - Max Moment, Shear & Required Section Modulus
Free simply supported beam calculator. Find maximum bending moment, shear/reactions and re...
📐 AISC / Statics
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U-Value Calculator - Conduction Heat Loss (Q = U·A·ΔT)
Free U-value calculator. Enter U-value, area and temperature difference to find conduction...
📐 ASHRAE / IECC
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Bolt Torque Calculator - Tightening Torque (T = K·D·F)
Free bolt torque calculator for metric and imperial bolts: tightening torque from preload,...
📐 T = K·D·F
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Column Buckling Calculator - Euler Critical Buckling Load (Pcr)
Free column buckling calculator. Find the Euler critical buckling load, critical stress an...
📐 Euler / AISC
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Darcy-Weisbach Head Loss Calculator - Pipe Friction (ft & psi)
Free Darcy-Weisbach head loss calculator. Find pipe friction head loss (ft), pressure drop...
📐 Darcy-Weisbach / Moody
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Degree Days Calculator - Annual Heating Energy (Degree-Day Method)
Free degree days calculator. Estimate annual heating energy load and fuel use from heating...
📐 ASHRAE / Degree-Day Method
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Orifice Flow Calculator - Flow Rate Through an Orifice (GPM)
Free orifice flow calculator. Find discharge flow rate (GPM), velocity and area for flow t...
📐 Torricelli / Bernoulli
FIRE Calculators
6 calculators
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Sprinkler Head Spacing & Coverage Calculator (NFPA 13)
Free sprinkler spacing calculator. Find the maximum sprinkler head spacing, coverage area ...
📐 NFPA 13
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Stairwell Pressurisation Airflow Calculator (NFPA 92)
Free stairwell pressurisation calculator. Estimate the supply airflow and fan duty to keep...
📐 NFPA 92 / ASHRAE
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Means of Egress Width Calculator (NFPA 101 / IBC)
Free egress width calculator. Work out required exit door and stair width from occupant lo...
📐 NFPA 101 / IBC
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Fire Fighting System BOQ & Budget Estimator
Free fire fighting BOQ estimator. Order-of-magnitude bill of quantities and cost for sprin...
📐 NFPA 13/14/72
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Fire Load Density Calculator (MJ/m²)
Free fire load density calculator. Work out the combustible fire load density in MJ/m² fr...
📐 Eurocode 1 / NBC
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Fire Water Storage Tank Calculator (NFPA 22)
Calculate total fire water storage for hydrant and sprinkler systems. NFPA 22 compliant. F...
📐 NFPA 13
PLUMBING Calculators
13 calculators
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NPSH Available (NPSHa) Calculator: Pump Cavitation Check
Free NPSH available calculator. Work out NPSHa from atmospheric pressure, static suction h...
📐 Hydraulic Institute (HI)
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Pipe Hanger & Support Spacing Calculator (MSS SP-69)
Free pipe hanger spacing calculator. Find the maximum support span and hanger load for ste...
📐 MSS SP-69 / ASTM A53
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Plumbing & Drainage BOQ & Budget Estimator
Free plumbing BOQ estimator. Order-of-magnitude bill of quantities and cost for water supp...
📐 Order-of-magnitude estimate
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Water Storage Tank Calculator (Sump & Overhead)
Calculate sump tank and overhead water tank capacity from building type and occupancy. IPC...
📐 IPC
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Rainwater Harvesting System Calculator
Size rainwater harvesting system - collection tank, recharge pit and self-sufficiency esti...
📐 IPC
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Free Online Swimming Pool Circulation Calculator
Calculate pool circulation flow (m³/h, L/s) and filter area from pool volume and turnover...
📐 IPC
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Free Online Solar Water Heater Sizing Calculator
Size a solar water heater: collector area and tank capacity from daily hot-water demand, t...
📐 NEC 690
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Free Online Hot Water Heater Sizing Calculator
Size a domestic or commercial hot water storage heater from occupancy, demand and temperat...
📐 IPC
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Free Online Grease Trap Sizing Calculator
Size a commercial kitchen grease trap / interceptor from meal count or drainage flow and r...
📐 IPC
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Free Online Roof Drainage & Gutter Sizing Calculator
Size roof drains, gutters and downpipes from roof area and rainfall intensity per the IPC....
📐 IPC
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Free Online Sump Pit & Ejector Pump Calculator
Size a sump pit volume and submersible drainage pump from inflow and pump cycles. IPC basi...
📐 IPC
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Free Online Septic Tank Design Calculator
Size a septic tank and soak pit from the number of users, sewage flow and retention time. ...
📐 IPC
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Free Online Water Hammer Pressure Surge Calculator
Calculate water hammer pressure surge from sudden valve closure using the Joukowsky equati...
📐 IPC / AWWA
ELECTRICAL Calculators
24 calculators
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Diesel Generator (DG) Fuel Tank Sizing Calculator
Free diesel generator fuel tank sizing calculator. Size the day tank and bulk fuel storage...
📐 ISO 8528
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Electrical BOQ & Budget Estimator (Concept Stage)
Free electrical BOQ estimator for early project budgeting. Get an order-of-magnitude bill ...
📐 Order-of-magnitude estimate
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Solar Panel Tilt Angle Calculator (Optimal PV Array Angle)
Free solar panel tilt angle calculator: find the optimal year-round, summer and winter til...
📐 NREL
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kVA to kW Calculator (kVA ⇄ kW, kVAR & Current)
Free kVA to kW calculator: convert kVA to kW (and kW to kVA) using power factor, with reac...
📐 IEEE
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Voltage Drop Calculator: Cable Volt Drop & % Loss (NEC)
Free voltage drop calculator: cable volt drop, % voltage loss and the 3% NEC limit for sin...
📐 NEC
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Cable Size Calculator (NEC 310): Online 3-Phase & LV Cable Sizing
Free online cable size calculator (NEC 310). Sizes single- and 3-phase LV cables by curren...
📐 IEC 60364-5-52
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Generator Sizing Calculator: DG Set kVA / kW & Wattage (NFPA 110)
Free DG set sizing calculator: find the generator kVA and kW from running load and motor s...
📐 ISO 8528 / IEEE
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Rooftop Solar PV System Sizing Calculator
Size rooftop solar PV system for the US - panels, inverter kW, annual generation and savin...
📐 NEC 690
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Power Factor Correction Calculator: Capacitor Bank kVAR Sizing
Free power factor correction calculator: capacitor bank kVAR sizing to improve power facto...
📐 NEC / IEEE 1459
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Earthing Calculator: Earth Electrode Resistance & Grounding (NEC 250)
Free earthing calculator: earth electrode resistance, number of earth pits and earthing co...
📐 NEC 250
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UPS Sizing Calculator (kVA + Battery Capacity)
Free UPS calculator: size a UPS in kVA and kW from your load and find the battery Ah for t...
📐 SAE J1772 / UL 1778
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Motor Starter Sizing Calculator (DOL / Star-Delta / VFD)
Size motor starters - DOL, star-delta, or VFD. Get FLC, starting current, contactor rating...
📐 NEC / UL 489
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EV Charger Load Calculator: Charging Load & Service Sizing (NEC 625)
Free EV charger load calculator: the electrical load (kW/A) an EV charger adds and the ser...
📐 SAE J1772
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Free Arc Flash Calculator (IEEE 1584)
Calculate arc flash incident energy and PPE category to IEEE 1584. Enter voltage, fault cu...
📐 IEEE 1584
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Free Online Elevator / Lift Motor Power Calculator
Calculate lift (elevator) motor power in kW and full-load current from rated load, speed a...
📐 NEC
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Lightning Protection Calculator: Rolling Sphere & Risk Assessment (NFPA 780)
Free lightning protection calculator: rolling-sphere protection radius, down-conductor cou...
📐 IS/NFPA 780
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Free Online Short Circuit Calculator
Calculate three-phase and single-phase fault current, fault MVA and switchgear breaking ca...
📐 NFPA / IEEE 141
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Free Online Busbar Sizing Calculator
Size copper or aluminium busbars for LV switchboards by current rating and cross-section. ...
📐 NEC / UL 891
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Free Online Total Harmonic Distortion (THD) Calculator
Calculate total harmonic distortion (THD) from non-linear loads and check against IEEE 519...
📐 IEEE 519
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Free Online HV/MV Cable Sizing Calculator (11kV / 33kV)
Size 11kV and 33kV medium/high-voltage cables by current rating, voltage drop and short-ci...
📐 NEC
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Neutral Current Calculator: 3-Phase Load Balancing (Per-Phase & Neutral)
Free neutral current calculator for unbalanced 3-phase loads: per-phase current, neutral c...
📐 NEC
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LPD Calculator: Lighting Power Density (W/ft² & W/m²)
Free LPD calculation: lighting power density in W/m² and W/ft², checked against ASHRAE 9...
📐 ASHRAE 90.1 2017 / NEC
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Free Online Battery Bank / DC UPS Sizing Calculator
Size a lead-acid or Li-ion battery bank (Ah and cell count) for a DC or UPS system from lo...
📐 SAE J1772 / IEEE 485
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Motor FLA Calculator - Full Load Amps from HP (1-φ & 3-φ)
Free motor FLA calculator. Convert motor HP to full-load amps for single- and three-phase ...
📐 NEC 430.250 / Motor Theory
Electrical Calculators
10 calculators
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Wire Size Calculator: Wire Gauge (AWG) & Conductor Size (IS / NEC)
Free wire size calculator: find the minimum wire gauge (AWG / mm2) and conductor size from...
📐 NEC 310
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Lux Calculator: Room Lux Level by the Lumen Method (IES)
Free lux calculator: find the lux level of a room or the number of light fittings needed w...
📐 SP 72 / NEC
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Standby Generator Sizing Calculator
Size standby diesel generators (DG sets) for buildings. Calculate required kVA based on co...
📐 NEC
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SWA Cable Sizing Calculator
Size steel wire armoured (SWA) cables for underground and outdoor installations. Calculate...
📐 NEC
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Fault Level Calculator
Calculate three-phase and single-phase fault levels at any point in an electrical distribu...
📐 NFPA / IEEE 141
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Transformer Sizing Calculator: Distribution & 3-Phase kVA Selection
Free transformer sizing calculator: distribution & 3-phase transformer kVA selection from ...
📐 IEEE C57.12 / NEC
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Generator Critical Load Calculator
Identify and calculate critical electrical loads that must be backed up by the emergency g...
📐 NEC
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SWA Cable Calculator: Armoured Cable Current Rating, Size & Voltage Drop
Free SWA cable calculator: current-carrying capacity, current rating, size and voltage dro...
📐 NEC
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IS Cable Sizing Calculator
Size electrical cables per Indian Standards (IS 732, IS 1554). Calculate conductor cross-s...
📐 IS 732 / IS 1554
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Conduit Size Calculator
Calculate the correct conduit size for any number of cables. Determine conduit diameter ba...
📐 NEC
Plumbing Calculators
9 calculators
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Gas Pipe Sizing Calculator & Chart: Natural Gas, LPG & Black Iron
Size natural gas and LPG pipes from total BTU load, pipe length and allowed pressure drop,...
📐 NFPA 58 / IGEM UP/2
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Pipe Sizing Calculator
Size water supply pipes for buildings using fixture unit method. Calculate pipe diameter b...
📐 IPC
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Natural Gas Pipe Sizing Calculator
Size natural gas (PNG) distribution pipes for residential and commercial buildings. Calcul...
📐 NFPA 58 / PNGRB
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Hot Water Pipe Sizing Calculator
Size hot water supply and return pipes for buildings. Calculate pipe diameter, insulation ...
📐 ASTM A653 / IPC
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Gas Appliance Sizing Calculator: Gas Load Calculation & BTU Demand
Free gas appliance sizing calculator: gas load calculation and total BTU/MJ demand for sto...
📐 NFPA 58 / IPC
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Water Supply Pipe Calculator
Calculate water supply pipe sizes for residential and commercial buildings. Determine dail...
📐 IPC
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Drainage Pipe Sizing Calculator
Size soil, waste, and vent pipes for building drainage systems. Calculate drain pipe diame...
📐 IPC
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Booster Pump Sizing Calculator
Size water booster pumps for building plumbing systems. Calculate pump flow, head, and mot...
📐 IPC / HI
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NBC Plumbing Calculator
Calculate the number of toilets, urinals and wash basins required as per NBC 2016 Part 9, ...
📐 NBC 2016 Part 9
Fire Fighting Calculators
6 calculators
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Fire Pump Calculator: Fire Fighting Pump Flow, Head & Capacity (NFPA 20)
Free fire pump calculator: fire fighting pump flow, head and capacity (duty point) for hyd...
📐 AWWA / NFPA 20
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Sprinkler Layout Calculator: Fire Sprinkler Spacing & Coverage (NFPA 13)
Work out sprinkler head spacing, coverage per head and the number of sprinklers for light,...
📐 IBC / NFPA 13
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Sprinkler System Calculator
Calculate total flow demand and design pressure for fire sprinkler systems. Covers wet pip...
📐 NFPA 13
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FM200 Fire Suppression Calculator
Calculate FM200 (HFC-227ea) agent quantity for clean agent fire suppression systems. Desig...
📐 NFPA 2001 / IBC
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Fire Hydrant Flow Calculator: Fire Flow Test (NFPA 14)
Calculate fire hydrant flow in GPM from a flow test, the available flow at 20 psi, and the...
📐 IBC / NFPA 22
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Sprinkler Hydraulic Calculator
Perform hydraulic calculations for fire sprinkler pipe networks. Calculate flow at each he...
📐 NFPA 13
Mechanical Calculators
2 calculators
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Compressed Air Pipe Sizing Calculator
Free compressed air pipe sizing calculator and chart: pick the air pipe diameter from SCFM...
📐 ISO 5941 / IBC
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Compressed Air System Calculator
Size compressed air compressors and air receivers for industrial systems. Calculate FAD de...
📐 ISO 1217 / IBC
AIR Calculators
1 calculators
Prefer the all-in-one tool? Open the MEP Calculators calculator dashboard to use every calculator on a single page.