Physics and Engineering

  • Circle Moment of Inertia (Area) Calculator
    Calculate the area moment of inertia of a solid circle from its radius or diameter using I = πr⁴/4 = πd⁴/64. Free engineering tool.
  • Partially Filled Circle Area Calculator
    Calculate the filled cross-section area and fill percentage of a partially filled circle or cylindrical tank from radius and fill depth.
  • Linear Thermal Expansion Calculator
    Calculate linear thermal expansion (ΔL = α·L₀·ΔT) from the expansion coefficient, original length, and temperature change. Free physics tool.
  • Solar Panel System Size Calculator
    Estimate the solar PV system size (kW) and number of panels you need from your daily energy use, peak sun hours, performance ratio and panel wattage.
  • Solar System Size Calculator
    Estimate the solar PV system size (kW) you need from your monthly kWh use, peak sun hours and a system derate factor. Free, instant solar sizing.
  • LC Resonant Frequency Calculator
    Calculate the resonant frequency of an LC tank circuit from inductance and capacitance using f = 1/(2π√(LC)). Supports H/mH/µH/nH and F/µF/nF/pF.
  • Speed, Distance & Time Calculator
    Free Speed, Distance & Time calculator. Solve for speed, distance, or time using d = s × t. Supports km, miles, meters, hours, minutes & seconds.
  • Density Calculator (Mass and Volume)
    Calculate density from mass and volume with ρ = m/V. Supports grams, kilograms, cm³, mL, liters and m³. Get results in g/cm³ and kg/m³ instantly.
  • Whole Home Electricity Bill Calculator
    Estimate your whole-home electricity bill by adding up each device's kWh, then applying your per-kWh rate and fixed fee. Works in any currency.
  • Watts, Volts, Amps & Ohms Calculator
    Solve for voltage, current, resistance or power from any two known values using Ohm's Law (V=IR) and the power equations P=VI, P=I²R, P=V²/R.
  • Appliance Energy Cost Calculator
    Calculate how much an appliance costs to run per day, month, and year from its wattage, hours of use, days per week, and your electricity rate per kWh.
  • Kinetic Friction Incline Acceleration Calculator
    Calculate the acceleration of a block sliding down a rough incline from angle, kinetic friction coefficient, and gravity using a = g(sinθ − μcosθ).
  • Coefficient of Restitution Calculator
    Calculate the coefficient of restitution (e) from collision velocities or from drop and bounce heights. Free, instant physics calculator.
  • Continuity Equation Flow Rate Calculator
    Solve the continuity equation A₁v₁ = A₂v₂ for fluid velocity and find volumetric flow rate Q = A·v in pipes and ducts instantly.
  • Electrical Energy Calculator
    Calculate electrical energy from power and time with E = P·t. Enter watts or kilowatts and seconds, minutes or hours to get joules, Wh and kWh.
  • Spring-Mass Oscillation Period Calculator
    Calculate the period, frequency and angular frequency of a mass on a spring using T = 2π√(m/k). Free online simple harmonic motion calculator.
  • Inverter Size Calculator
    Calculate the right inverter size in VA from your total load in watts and power factor, with a safety margin for surge headroom and reliable operation.
  • Elastic Collision Calculator
    Compute the final velocities of two objects after a 1D elastic collision from their masses and initial velocities. Conserves momentum and kinetic energy.
  • EV Cost Per Mile Calculator
    Calculate the energy cost per mile of your electric vehicle from its efficiency (miles/kWh) and your electricity rate. See cost per 100 miles and trip cost.
  • Speaker Impedance Calculator
    Calculate total speaker impedance for series or parallel wiring. Enter up to 4 speaker impedances in ohms to find the combined load on your amplifier.
  • Watts to Amps Calculator (Three Phase)
    Convert watts to amps for three-phase AC circuits. Enter power, line-to-line voltage and power factor to get line current in amperes instantly.
  • Vector Magnitude Calculator
    Calculate the magnitude (length) of a 2D or 3D vector from its x, y, z components using |v| = √(x²+y²+z²). Fast and accurate.
  • Resultant Vector Calculator
    Add 2 or 3 vectors by their X and Y components to find the resultant vector's magnitude and direction angle θ. Free, instant 2D vector addition.
  • 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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