Fluid Calculator

  • Water Density by Temperature Calculator
    Calculate the density of water at any temperature from 0 to 100 °C using the standard empirical polynomial. Results in kg/m³ and g/cm³.
  • GPM to CFS Converter
    Convert gallons per minute (GPM) to cubic feet per second (CFS) instantly. Enter a flow rate and get an accurate CFS value using CFS = GPM / 448.831.
  • CFS to GPM Converter
    Convert cubic feet per second (CFS) to gallons per minute (GPM) instantly. Uses 1 CFS = 448.831 US GPM. Free flow-rate conversion tool.
  • Liters per Second to GPM Converter
    Convert liters per second (L/s) to US gallons per minute (GPM) instantly. Enter a flow rate and get the exact GPM value using the 15.8503 factor.
  • Acre-Feet to Gallons Calculator
    Convert acre-feet to US gallons instantly. Enter acre-feet and get the exact gallon volume using 1 acre-foot = 325,851 gallons.
  • Relative Humidity from Dew Point Calculator
    Calculate relative humidity (%) from air temperature and dew point using the Magnus formula. Fast, accurate, and free online RH calculator.
  • Water Flow From Tank Time Calculator
    Calculate the time to fully drain a tank through a hole using Torricelli law. Enter tank area, hole area, liquid height and discharge coefficient.
  • Pump Efficiency Calculator
    Calculate pump efficiency from flow rate, head, fluid density and shaft power using η = (ρgQH)/P. Get hydraulic power and efficiency percentage instantly.
  • Absolute to Gauge Pressure Calculator
    Convert absolute pressure to gauge pressure instantly. Enter absolute and atmospheric pressure to find gauge pressure using Pg = Pabs − Patm.
  • Water Vapor Pressure Calculator
    Calculate the saturation vapor pressure of water at any temperature using the Tetens formula. Get results in kPa, hPa (mbar), and mmHg.
  • Hoop Stress Calculator (Thin-Wall Pipe)
    Calculate hoop (circumferential) and axial stress in a thin-wall pressurized pipe or cylinder using σ = PD/2t. Enter pressure, diameter and wall thickness.
  • Pipe Wall Thickness Calculator (Barlow's Formula)
    Calculate minimum pipe wall thickness from internal pressure, outside diameter, and allowable stress using Barlow formula t = PD/(2S). In inches and mm.
  • Sprinkler Flow Rate Calculator
    Calculate fire sprinkler discharge flow rate (GPM) from K-factor and pressure using Q = K times the square root of P. Free hydraulic calculator.
  • Air Flow Rate (CFM) Calculator
    Calculate airflow in CFM from air velocity (ft/min) and rectangular duct dimensions. Uses CFM = velocity × duct area for HVAC sizing.
  • Pipe Water Velocity Calculator (GPM & Diameter)
    Calculate water velocity (ft/s) in a pipe from flow rate in GPM and inside diameter in inches. Fast, accurate plumbing and pipe-sizing tool.
  • Water Column to Pressure Calculator
    Convert a water column height (feet or inches of water) into pressure in PSI, kPa and bar. Uses ftH2O x 0.4335 and inH2O x 0.03613.
  • Wind Load Pressure Calculator
    Calculate dynamic wind pressure with q = ½ρv². Enter wind speed and air density to get pressure in pascals, plus total wind force on an area.
  • Flow Rate to Velocity Converter
    Convert volumetric flow rate (Q) and pipe diameter into fluid velocity. Supports m³/s, L/s, GPM and mm, cm, in. Free pipe flow velocity calculator.
  • Darcy-Weisbach Pressure Drop Calculator
    Calculate pressure drop in a pipe using the Darcy-Weisbach equation from friction factor, length, diameter, density and velocity. Get Pa, kPa, bar and head loss.
  • Pump Power (HP) Calculator
    Calculate pump brake horsepower (BHP) and water horsepower from flow rate (GPM), total head (ft), specific gravity, and pump efficiency.
  • Valve Kv Flow Coefficient Calculator
    Calculate the valve flow coefficient Kv (metric) from flow rate, specific gravity and pressure drop. Get equivalent Cv too. Free engineering tool.
  • SCFM to ACFM Calculator
    Convert SCFM to ACFM using actual pressure and temperature. Free airflow conversion calculator for compressors, blowers, and HVAC systems.
  • Head Loss per 100 ft Calculator (Hazen-Williams)
    Calculate Hazen-Williams friction head loss in feet of water per 100 ft of pipe from flow rate (gpm), inside diameter, and C coefficient. US units.
  • Pump Hydraulic Power (kW) Calculator
    Calculate pump hydraulic power in kW from fluid density, gravity, flow rate and head using P = ρgQH. Also outputs watts, horsepower and shaft power.

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