Calculator Hub

28 live calculators across 6 engineering disciplines

Business
2 calculators

Markup & Margin

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Calculate selling price from cost, or find your true margin from a given price.

PricingBidding

Labor Rate / Wrap Rate

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Build fully-loaded labor rates with fringe, overhead, G&A, and profit for government service contracts.

FAR Part 31Labor
Electrical
9 calculators

Residential Load Calculation

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NEC Article 220 compliant load calculation for dwelling units.

NEC 220

Panel Schedule Builder

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Build and balance panel schedules with automatic phase assignment.

PanelSchedule

Voltage Drop Calculator

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Calculate voltage drop per NEC 210.19 with minimum size recommendation.

NEC 210

Conductor Ampacity

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NEC Table 310.16 sizing with ambient temp and conduit fill derating.

NEC 310

Commercial Load Calculation

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NEC 220 Part III demand load analysis by occupancy type.

NEC 220Commercial

Feeder Sizing

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Size feeder conductors, OCPD, neutral, and ground per NEC 215.

NEC 215

Service Sizing

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Service entrance conductor, disconnect, and GEC sizing per NEC 220 & 230.

NEC 230

Transformer Sizing

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kVA selection, primary/secondary OCPD and conductor sizing per NEC 450.

NEC 450

Demand Load Summary

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Aggregate multiple panels and feeders into a main service calculation.

Multi-Panel
Mechanical
4 calculators

Cooling Load Estimator

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Estimate peak cooling load (BTU/hr & tons) by occupancy type, area, and climate zone.

ASHRAECooling

Duct Sizing Calculator

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Size rectangular and round ducts by equal friction method. Outputs velocity and friction rate.

ASHRAEHVAC

HVAC Heating Load

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Manual J simplified heating load calculation for commercial and residential spaces.

Manual J

Hydronic Pipe Sizing

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Size hydronic heating and chilled water piping systems by flow rate and velocity.

HydronicASHRAE
Civil
4 calculators

Stormwater Runoff (Rational)

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Compute peak runoff Q = CiA per the Rational Method for drainage design.

HydrologyIDF

Concrete Volume Calculator

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Compute concrete volume and yardage for footings, slabs, columns, and walls.

ConcreteVolume

Simple Beam Load

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Calculate reactions, shear, and bending moment for simply supported beams.

StructuralBeam

Retaining Wall Check

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Sliding and overturning stability check for gravity retaining walls.

StructuralGeotechnical
Plumbing
3 calculators

Fixture Unit Load (Hunter's)

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Calculate total fixture units and recommended pipe size per IPC/UPC Hunter's method.

IPCUPCFixture

Pipe Flow & Sizing

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Hazen-Williams equation — GPM to pipe diameter, velocity, and head loss per 100 ft.

Hazen-WilliamsGPM

Water Heater Sizing

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First-hour rating and storage volume sizing for commercial water heaters.

PlumbingThermal
Fire Protection
3 calculators

Sprinkler Density / Area

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NFPA 13 density/area method — design density, area of operation, and flow demand.

NFPA 13Sprinkler

K-Factor Flow Calculator

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Calculate sprinkler discharge (GPM) from K-factor and residual pressure. Solve for pressure required.

NFPA 13K-Factor

Fire Pump Sizing

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Net pump pressure and flow demand sizing per NFPA 20.

NFPA 20Pump
IT / Low Voltage
3 calculators

Conduit Fill Calculator

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NEC Chapter 9 Table 1 — check conduit fill percentage for mixed cable runs.

NEC Ch. 9Conduit

PoE Power Budget

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Calculate total PoE draw, switch budget utilization, and required UPS capacity.

PoEIEEE 802.3

Fiber Strand Count

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Calculate required fiber strand count by pathway, redundancy, and protocol.

FiberTIA-568