Physics and Engineering

  • EV vs Gas Cost per Mile Calculator
    Compare the cost per mile of driving an electric vehicle versus a gas car. Enter kWh/mile, electricity price, gas price, and MPG to see your savings.
  • Electricity Usage From Meter Reading Calculator
    Calculate kWh used between two electricity meter readings. Enter current and previous readings plus a meter multiplier to get usage and estimated cost.
  • kWh to BTU Calculator
    Convert kilowatt-hours (kWh) to British Thermal Units (BTU) instantly. Enter kWh and get BTU using the factor 1 kWh = 3412.142 BTU.
  • Amps to Milliamps Calculator
    Convert amps (A) to milliamps (mA) instantly. Enter a current value in amperes and get the equivalent in milliamps using mA = A × 1000.
  • Stefan-Boltzmann Radiation Calculator
    Calculate thermal radiation power with the Stefan-Boltzmann law P = εσAT⁴. Enter emissivity, surface area and absolute temperature to get watts radiated.
  • Battery Amp-Hours Needed Calculator
    Calculate the battery amp-hours (Ah) needed from watts, runtime hours and voltage. Includes depth-of-discharge adjustment for any 12V, 24V or 48V battery.
  • Water Flow Rate Through a Hose Calculator
    Estimate water flow rate through a hose from inner diameter, supply pressure and discharge coefficient. Get liters/min, GPM and exit velocity instantly.
  • Battery State of Charge Calculator
    Estimate battery State of Charge (SOC %) from a measured voltage reading using linear interpolation between empty (Vmin) and full (Vmax) voltages.
  • Reynolds Number for Pipe Flow Calculator
    Calculate the Reynolds number for fluid flow in a pipe from density, velocity, diameter and viscosity. Re = ρvD/μ. Find if flow is laminar or turbulent.
  • Electric Field Between Plates Calculator
    Calculate the uniform electric field between two parallel plates using E = V/d from the voltage and plate separation. Fast, free physics tool.
  • Quarter Wave Antenna Length Calculator
    Calculate the ideal quarter-wave antenna length from frequency and velocity factor. Get results in meters, cm and inches instantly.
  • 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.
  • Resultant Force Calculator
    Calculate the resultant of two forces acting at an angle using the parallelogram law. Get magnitude and direction in newtons instantly.
  • Two-Support Beam Reaction Calculator
    Calculate support reactions R1 and R2 for a simply supported beam with a single point load using static equilibrium equations.
  • Kilowatts to Watts Calculator
    Convert kilowatts (kW) to watts (W) instantly. Enter a power value in kW and get the exact result in watts using W = kW × 1000.
  • Watts to Kilowatts Calculator
    Convert watts (W) to kilowatts (kW) instantly. Just divide power in watts by 1000 to get kilowatts. Fast, accurate, free W to kW converter.
  • Average Acceleration Calculator
    Calculate average acceleration from initial and final velocity over a time interval using a = Δv / Δt. Free, instant, with worked example.
  • Linear Velocity from Angular Velocity Calculator
    Calculate linear (tangential) velocity from radius and angular velocity using v = r·ω. Enter radius in meters and ω in rad/s to get speed in m/s.
  • 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.
  • Lumens Needed Calculator
    Calculate how many lumens you need to light a room. Multiply floor area (m²) by the recommended lux level to get total lumens for any space.
  • Electric Potential of a Point Charge Calculator
    Calculate the electric potential V of a point charge using V = kQ/r. Enter the charge in coulombs and distance in meters to get volts instantly.
  • Density Calculator
    Calculate density from mass and volume using ρ = m / V. Get results in kg/m³ and g/cm³ instantly. Free, accurate physics density calculator.

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