Fluid Calculator

  • Hydrostatic Pressure Calculator
    Calculate hydrostatic (fluid) pressure with P = ρgh. Get gauge and absolute pressure in Pa, kPa, bar and atm from density, gravity and depth.
  • Water Hammer Pressure Surge Calculator
    Calculate water hammer pressure surge with the Joukowsky equation. Enter fluid density, pressure wave speed and velocity change to get the surge in Pa, kPa, bar and psi.
  • V-Notch Weir Flow Calculator
    Calculate discharge over a triangular (V-notch) weir from head, notch angle, and discharge coefficient using the standard weir equation.
  • Rectangular Weir Discharge Calculator
    Calculate discharge (flow rate) over a rectangular weir from crest width, head and discharge coefficient using Q = (2/3)·Cd·L·√(2g)·H^1.5.
  • Colebrook-White Friction Factor Calculator
    Solve the implicit Colebrook-White equation for the Darcy friction factor f from Reynolds number, pipe roughness and diameter. Free engineering tool.
  • Hydraulic Press Force Calculator
    Calculate hydraulic press output force using Pascal's law. Enter input force and both piston areas to find F2 = F1 × (A2/A1) plus system pressure.
  • Swamee-Jain Friction Factor Calculator
    Calculate the Darcy friction factor for turbulent pipe flow using the Swamee-Jain explicit equation from roughness, diameter, and Reynolds number.
  • NPSH Available Calculator
    Calculate Net Positive Suction Head available (NPSHa) for centrifugal pumps to avoid cavitation, using surface pressure, vapor pressure, density and head losses.
  • Pipe Flow Rate from Diameter & Velocity Calculator
    Calculate volumetric water flow rate (Q) in a pipe from inner diameter and velocity. Get results in m³/s, L/s, and m³/h instantly.
  • GPM to LPM Flow Rate Converter
    Convert flow rate from gallons per minute (GPM) to liters per minute (LPM) instantly. Also shows liters per hour and cubic meters per hour.
  • Pipe Cross-Sectional Area Calculator
    Calculate the internal cross-sectional area of a pipe from its inside diameter using A = πD²/4. Supports mm, cm, inches and meters.
  • Flow Rate Calculator (Volume ÷ Time)
    Calculate volumetric flow rate from volume and time with Q = V/t. Convert results to L/s, L/min, m³/h and GPM instantly. Free online flow rate calculator.
  • Gallons Per Hour (GPH) Calculator
    Calculate gallons per hour (GPH) flow rate from a volume in gallons and elapsed time in hours. Free, instant GPH and GPM results.
  • Keg Volume Calculator
    Find how many beers are in a keg. Enter keg size and serving ounces to get servings, gallons, fluid ounces, and liters instantly.
  • Barrel Volume Calculator
    Calculate the volume of a barrel, cask, or drum using the Kepler approximation. Enter height and the middle & end diameters to get liters and gallons.
  • Pressure Head Calculator
    Calculate pressure head h = P/(ρg) in meters of fluid from pressure, density and gravity. Free online hydraulics & fluid mechanics tool.
  • Hydraulic Horsepower Calculator
    Calculate hydraulic horsepower (HHP) from flow rate in GPM and pressure in PSI using HHP = (Q × P) / 1714. Fast, free, accurate.
  • Milliliters to Fluid Ounces Converter
    Convert milliliters (mL) to US fluid ounces (fl oz) instantly. Enter a volume and get the precise fluid ounce result using floz = ml / 29.5735.
  • Antoine Equation Vapor Pressure Calculator
    Calculate vapor pressure from Antoine equation coefficients (A, B, C) and temperature. Get results in mmHg, atm, bar and kPa instantly.
  • Dynamic to Kinematic Viscosity Calculator
    Convert dynamic (absolute) viscosity to kinematic viscosity with ν = μ/ρ. Enter μ in Pa·s and density ρ in kg/m³ to get ν in m²/s, cSt and St.
  • Flow Velocity from GPM and Pipe Diameter Calculator
    Calculate water flow velocity (ft/s) from flow rate in GPM and inside pipe diameter in inches. Free pipe velocity calculator with formula and example.
  • Minor Head Loss Calculator
    Calculate minor (local) head loss in pipe fittings using hL = K·v²/(2g). Enter the loss coefficient K and flow velocity to get head loss in meters.
  • Rectangular Pool Volume Calculator
    Calculate how many gallons of water your rectangular pool holds. Enter length, width, and average depth in feet to get the volume instantly.
  • Pump Affinity Laws Calculator
    Use the pump affinity laws to find new flow, head, and power when impeller speed changes. Enter initial values and the new RPM to get instant results.

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