Trades Unit Converter - Pressure, Flow, Temperature & More for Industrial Workers

How It Works

1. Select Category

   Choose a conversion category: pressure, liquid flow, gas/air flow, temperature, torque, length, water chemistry, or electrical. Categories are organized by trade discipline so HVAC, plumbing, instrumentation, and mechanical conversions are easy to find.

2. Enter Value and Source Unit

   Type the value you want to convert and select the source unit. For example, enter 28 and select inches of water column (inWC) to convert a pressure reading.

3. View All Conversions at Once

   The converter displays the value in every other unit of the category simultaneously - no target-unit picking. For the 28 inWC example you see PSI, kPa, bar, mbar, MPa, mmHg, inHg, atm, cmWC, and ft H2O together, each with a copy button.

4. Enter Conditions for Gas Flow

   For SCFM/ACFM work, enter altitude and temperature; the tool shows the standard-atmosphere pressure it uses. Confirm the vendor standard and actual site conditions before using the result for equipment comparisons.

5. Export the Conversion Report

   Generate a PDF with the inputs, converted values, assumptions, source warnings, and residual gaps for the record.

Built For

• Instrument technicians converting pressure readings between inWC, PSI, kPa, bar, and mmHg during calibration
• HVAC technicians screening SCFM and ACFM differences before checking the equipment reference standard
• Plumbers converting between GPM and liters per minute, or grains per gallon to ppm for water hardness
• Millwrights converting torque between Newton-meters, foot-pounds, and inch-pounds during equipment assembly
• Electricians doing HP, kW, kVA, and arithmetic amp checks before NEC/table review
• Water treatment operators converting between mg/L, ppm, and grains per gallon for hardness and dosing checks
• Mechanical engineers converting valve Cv to Kv for metric equipment specifications

Features & Capabilities

Pressure Conversions

Convert between PSI, inWC (inches of water column), cmWC, ft H2O, kPa, MPa, bar, mbar, mmHg, atm, and inHg. Includes the critical inWC-to-PSI conversion (1 PSI = 27.68 inWC) used constantly in HVAC and instrumentation work.

Flow Conversions

Convert between GPM, LPM, m3/hr, SCFM, ACFM, and ft3/hr style rows. The SCFM/ACFM conversion uses altitude, temperature, and a disclosed reference standard; vendor and site conditions still govern equipment decisions.

Temperature Conversions

Convert between Fahrenheit, Celsius, Kelvin, and Rankine with the standard offset formulas and common reference points.

Torque Conversions

Convert between foot-pounds (ft-lbs), Newton-meters (Nm), inch-pounds (in-lbs), and kilogram-meters (kgm). Essential for bolt torque specifications, which arrive in different units depending on whether the manufacturer is domestic or metric.

Water Chemistry

Convert between ppm, mg/L, and grains per gallon. The grains-per-gallon to ppm conversion (1 GPG = 17.1 ppm) is used daily in water treatment and softener sizing. The ppm = mg/L equivalence assumes dilute aqueous solutions near 25 C.

Valve Cv/Kv Conversion

Convert Cv (US flow coefficient) to Kv using the rounded relationship Kv = 0.865 x Cv. Final valve sizing still needs the applicable ISA/IEC equation basis, fluid properties, pressure drop, and manufacturer data.

Assumptions

• SCFM reference used by this app is 14.696 PSIA and 68 degrees F (528 degrees R); humidity and vendor alternate standards are not modeled.
• Water density/reference-fluid effects are not modeled for pressure-head or water-chemistry rows beyond disclosed rounded factors.
• Pressure conversions use rounded shop factors based on common defined relationships; use NIST SP 811 full precision for metrology-grade work.
• Temperature conversions use standard offset formulas (F = C x 9/5 + 32; K = C + 273.15).
• Cv/Kv conversion uses the rounded relationship Kv = 0.865 x Cv.
• Water chemistry ppm assumed equivalent to mg/L for dilute aqueous solutions at standard temperature and pressure

Limitations

• SCFM to ACFM conversion requires user-entered actual pressure, temperature, and altitude - defaults to sea level if not specified
• Does not account for gas compressibility factors (Z-factor) for non-ideal gas behavior at high pressures or cryogenic temperatures
• Water chemistry conversions assume dilute solutions - concentrated brines and chemical solutions require density corrections
• Cv/Kv conversion applies to liquid flow only - gas and steam Cv calculations require additional factors (expansion factor, specific heat ratio)
• Electrical unit conversions include a user-entered power factor but do not model harmonics, motor code FLA, conductor derating, overload sizing, or phase-angle waveform detail.
• Does not include viscosity, density, or other fluid property conversions beyond the listed categories

References

• NIST Special Publication 811 - Guide for the Use of the International System of Units (SI)
• CAGI/ASME - Standard conditions for compressed air flow measurement (14.696 PSIA, 68deg F)
• ISA-75.01.01 - Industrial-Process Control Valves: Flow Equations for Sizing (Cv/Kv definitions)
• IEC 60534-2-1 - Industrial-Process Control Valves: Flow Capacity (metric Kv standard)
• AWWA B100 - Granular Filter Material (grains per gallon to ppm conversion for water treatment)
• ASHRAE Handbook - Fundamentals, Chapter 1: Psychrometrics (SCFM/ACFM altitude and temperature corrections)

Frequently Asked Questions