Free HVAC, Electrical and Plumbing Calculators
TierMenu’s free calculators show their math. 25 free trade and business calculators for technicians. Instant results, imperial by default, with the formula behind every number. No signup. How we build and check each formula.
HVAC
Airflow, duct sizing, air properties and heat loss.
HVACDuctulator: Duct Size CalculatorRound duct diameter from CFM and friction rate, velocity, and the equivalent rectangular size.Open calculator HVACPsychrometric CalculatorWet bulb, dew point, humidity ratio, enthalpy and specific volume from two readings and altitude.Open calculator HVACCFM CalculatorAirflow from sensible Btu/h and temperature split, or Btu/h from measured airflow.Open calculator HVACStatic Pressure CalculatorTotal external static pressure from supply and return readings, with % of rated maximum.Open calculator HVACHeat Loss CalculatorQuick room or house heat loss from walls, windows, doors, ceiling, floor and air leakage.Open calculator HVACBTU to kW ConverterConvert Btu/h, kilowatts and tons of refrigeration in any direction.Open calculator HVACBTU CalculatorEstimate room air conditioner capacity from floor area and the listed adjustments.Open calculator HVACSuperheat CalculatorCalculate superheat from suction pressure and suction-line temperature.Open calculator HVACSubcooling CalculatorCalculate subcooling from liquid pressure and liquid-line temperature.Open calculator HVACRefrigerant PT ChartsInteractive saturation lookups, full pressure-temperature tables and printable PDFs for four refrigerants.Open calculator
Electrical
Voltage drop, power, transformers and conduit bends.
ElectricalVoltage Drop CalculatorDrop in volts and percent for copper or aluminum, plus the smallest wire for a target %VD.Open calculator ElectricalOhm's Law CalculatorEnter any two of volts, amps, ohms and watts to solve the other two.Open calculator ElectricalThree-Phase Power CalculatorkW and kVA from volts, amps and power factor, or solve for current or voltage.Open calculator ElectricalkVA CalculatorConvert between kVA, volts and amps for single- and three-phase systems.Open calculator ElectricalAmperage CalculatorAmps from watts, kW or horsepower with voltage, power factor and phase.Open calculator ElectricalTransformer Sizing CalculatorRequired kVA with spare capacity and the next standard size, plus primary and secondary FLA.Open calculator ElectricalConduit Bending CalculatorOffsets, 3-point and 4-point saddles, and 90° stubs with exact math and field rules.Open calculator ElectricalOffset Bend CalculatorDistance between bends and shrink for a conduit offset at any common angle.Open calculator ElectricalWire Size CalculatorSelect a wire size using the greater of ampacity and voltage-drop requirements.Open calculator
Plumbing
Friction loss, pipe sizing, volume and flow.
PlumbingFriction Loss CalculatorHazen-Williams pressure loss per 100 ft and over your run, plus head loss and velocity.Open calculator PlumbingPipe Volume CalculatorGallons per foot and total water volume for copper, PVC, steel and PEX.Open calculator PlumbingPipe Size CalculatorSmallest pipe that keeps velocity under your limit for a given flow.Open calculator PlumbingFlow Rate CalculatorGPM from velocity and pipe size, or from a timed bucket test.Open calculator
Business
Labor rates and task prices built from your own costs.
BusinessLabor Rate CalculatorCalculate a billable hourly rate from crew capacity, labor cost, overhead and target margin.Open calculator BusinessFlat Rate Price CalculatorPrice one service task from labor, parts, a fixed fee, rounding and an optional member discount.Open calculator BusinessMarkup CalculatorPrice from cost and markup, markup and margin from a price, or the price that hits a target margin.Open calculator
Results are estimates for reference. Verify against manufacturer data and your local code.
Know the numbers. Now price the job.
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