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Physics Fundamentals

Physics
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Free online calculators for every physics topic. Enter your values, get instant results with step-by-step solutions. No login, no ads.

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All topicsClassical MechanicsWaves & OpticsThermodynamicsElectromagnetismModern Physics
Classical MechanicsR = v₀²sin2θ / g

Projectile Motion Calculator

Range, height, time of flight

Calculate range, maximum height, time of flight and full trajectory for any projectile. Enter launch speed and angle — get every kinematic quantity instantly.

RangeMax heightFlight timeTrajectory
Calculate →
Classical MechanicsKE = ½mv²

Kinetic Energy Calculator

KE, mass or velocity — solve any

Calculate kinetic energy from mass and velocity, or solve for mass or velocity when KE is known. Multiple unit systems with real-world examples.

Kinetic energyMassVelocityMomentum
Calculate →
ElectromagnetismV = IR · P = IV

Ohm's Law Calculator

V, I, R and P — enter any two

Calculate voltage, current, resistance and power. Enter any two known values — the calculator instantly solves for all four. Includes interactive circuit diagram.

VoltageCurrentResistancePower
Calculate →
Kinematicsh = ½gt² · v = gt

Free Fall Calculator

Distance, velocity and time

Calculate distance fallen, velocity reached, or time in free fall. Works for Earth, Moon, Mars and custom gravity. Shows the full kinematic solution.

DistanceVelocityTimeGravity
Calculate →
Classical MechanicsF = ma

Newton's Second Law Calculator

Force, mass or acceleration

Calculate force, mass or acceleration using Newton's second law. Multiple force units with worked examples — links directly to our F=ma articles.

ForceMassAccelerationWeight
Calculate →
Waves & OscillationsT = 2π√(L/g)

Pendulum Period Calculator

Period, frequency, length, gravity

Calculate pendulum period, frequency, length or gravity. Works on any planet. Live pendulum animation updates with your result.

PeriodFrequencyLengthGravity
Calculate →
Waves & Opticsv = fλ

Wave Speed Calculator

Speed, frequency or wavelength

Solve for wave speed, frequency or wavelength. Covers sound in air, water and steel; light in vacuum and glass. EM spectrum reference included.

Wave speedFrequencyWavelengthMedium
Calculate →
ThermodynamicsPV = nRT

Ideal Gas Law Calculator

P, V, n or T — solve any variable

Solve PV=nRT for pressure, volume, moles or temperature. Full unit conversion (atm, Pa, kPa, bar). Shows combined gas law comparisons.

PressureVolumeMolesTemperature
Calculate →
Classical MechanicsPE = mgh

Gravitational PE Calculator

PE, mass, height or gravity

Calculate gravitational potential energy, or solve for mass, height or gravity. Custom planet presets. Energy bar comparing PE vs KE at different heights.

Potential energyMassHeightGravity
Calculate →
Classical Mechanicsp = mv

Momentum Calculator

Momentum, impulse, collisions

Calculate momentum and impulse. Includes elastic and inelastic collision outcomes — enter two objects and solve for post-collision velocities.

MomentumImpulseMassVelocity
Calculate →
Classical Mechanicsa_c = v²/r

Circular Motion Calculator

Centripetal force, acceleration, period

Calculate centripetal acceleration, centripetal force, angular velocity and orbital period. Satellite orbit examples built in.

Centripetal forceAccelerationPeriodAngular velocity
Calculate →
Kinematicsv² = u² + 2as

SUVAT Calculator

All 5 kinematic equations

Enter any 3 of the 5 SUVAT variables and solve for the remaining two. Shows which equation was used at each step. Essential for A-level physics.

suva
Calculate →
Classical MechanicsF = −kx

Hooke's Law Calculator

Spring force, constant, extension

Calculate spring force, spring constant or extension using Hooke's law. Also computes spring potential energy. Live spring compression visualisation.

ForceSpring constantExtensionSpring PE
Calculate →
Waves & Opticsf' = f·(v±v_o)/(v∓v_s)

Doppler Effect Calculator

Observed frequency, source & observer speed

Calculate the observed frequency shift due to the Doppler effect. Works for sound and light (redshift). Ambulance and radar examples.

Observed frequencySource speedObserver speedWave speed
Calculate →
Waves & Opticsn₁sinθ₁ = n₂sinθ₂

Snell's Law Calculator

Refraction angle, critical angle, TIR

Calculate refraction angle, find the critical angle for total internal reflection, and look up refractive indices for common materials. Live ray diagram.

Refraction angleCritical angleRefractive indexTIR
Calculate →
Classical Mechanicsτ = rFsinθ

Torque Calculator

Torque, force, lever arm, angle

Calculate torque in Newton-metres or foot-pounds. Solve for force, lever arm length or angle. Practical wrench and bolt examples.

TorqueForceLever armAngle
Calculate →
Fluid MechanicsF_b = ρVg

Buoyancy Calculator

Archimedes' principle — sink or float

Calculate buoyant force using Archimedes' principle. Determine whether an object sinks or floats. Fluid density lookup for water, seawater, oil.

Buoyant forceDisplaced volumeFluid densityObject density
Calculate →
Classical MechanicsW = Fd · P = W/t

Work & Power Calculator

Work done, power output, efficiency

Calculate work done, power output or time. Convert between watts, horsepower and kilowatts. Machine efficiency comparison.

Work donePowerForceTime
Calculate →
Gravitationv_esc = √(2GM/r)

Escape Velocity Calculator

Escape speed for any planet or body

Calculate escape velocity for Earth, Moon, Mars, Jupiter, the Sun or any custom body. Shows why rockets need such high speeds to leave orbit.

Escape velocityPlanet massPlanet radiusSurface gravity
Calculate →
ThermodynamicsΔL = αL₀ΔT

Thermal Expansion Calculator

Linear, area and volumetric expansion

Calculate thermal expansion for linear, area and volumetric cases. Material library (steel, glass, aluminium, concrete). Engineering applications.

Length changeExpansion coefficientTemperature changeVolume change
Calculate →
ElectromagnetismF = kQ₁Q₂/r²

Coulomb's Law Calculator

Force between two charges — solve F, Q or r

Calculate the electrostatic force between two point charges, or solve for charge or distance when force is known. Shows attraction/repulsion and a live force-diagram.

ForceCharge 1Charge 2Distance
Calculate →
Modern PhysicsN = N₀(½)^(t/t½)

Half-Life & Radioactive Decay Calculator

Remaining quantity, elapsed time or half-life

Calculate remaining radioactive quantity after any elapsed time, or solve for half-life or elapsed time. Includes a live decay curve and isotope presets.

Remaining amountElapsed timeHalf-lifeDecay constant
Calculate →
Classical MechanicsE = σ/ε

Stress, Strain & Young's Modulus Calculator

Stiffness, extension or required force

Calculate Young's modulus, extension, or required force for any material under tension. Material library and live stretching diagram.

Young's modulusStressStrainForce
Calculate →
Modern PhysicsKE_max = hf − φ

Photoelectric Effect Calculator

Kinetic energy, work function or frequency

Calculate maximum photoelectron kinetic energy, a metal's work function, or the frequency needed for a target energy, using Einstein's photoelectric equation.

Kinetic energyWork functionThreshold frequencyStopping voltage
Calculate →
ElectromagnetismR_s=ΣR · 1/R_p=Σ1/R

Resistors in Series & Parallel Calculator

Total resistance, current & voltage per resistor

Calculate total resistance for any number of resistors in series or parallel, plus current and voltage across each one.

Total resistanceCurrent per resistorVoltage per resistor
Calculate →
ElectromagnetismE = kQ/r²

Electric Field Strength Calculator

Field strength, force, or source charge

Calculate the electric field from a point charge, the force on a test charge, or the source charge producing a field. Live field-line diagram.

Field strengthForceSource chargeDistance
Calculate →
ElectromagnetismQ=CV, E=½CV²

Capacitor Charge & Energy Calculator

Charge stored, energy stored, or capacitance

Calculate the charge and energy stored in a capacitor, or solve for capacitance or voltage. Live charging diagram.

ChargeEnergyCapacitanceVoltage
Calculate →
Modern Physicsλ = h/mv

de Broglie Wavelength Calculator

Wavelength, velocity, or mass of any particle

Calculate the de Broglie wavelength associated with any moving particle, or solve for velocity or mass.

WavelengthMomentumMassVelocity
Calculate →
Modern PhysicsEₙ = −13.6/n² eV

Bohr Model Energy Levels Calculator

Hydrogen energy levels and transitions

Calculate hydrogen atom energy levels, or the energy, frequency, and wavelength of a photon for any electron transition.

Energy levelTransition energyFrequencyWavelength
Calculate →
Gravitationg = GM/r²

Gravitational Field Strength Calculator

Surface gravity, mass, or distance

Calculate the gravitational field strength (surface gravity) of any body, or solve for its mass or distance from its centre. Planet presets.

Field strengthMassDistance
Calculate →
ElectromagnetismF = qvBsinθ · F = BILsinθ

Magnetic Force Calculator

Force on a charge, a wire, or field strength

Calculate the magnetic force on a moving charge or a current-carrying wire, or solve for the field strength from a measured force.

ForceField strengthChargeCurrent
Calculate →
ElectromagnetismEMF = −NΔΦ/Δt

Faraday's Law — Induced EMF Calculator

EMF, coil turns, or time interval

Calculate the EMF induced by a changing magnetic flux, or solve for the number of coil turns or the time interval.

Induced EMFTurnsFlux changeTime
Calculate →
Modern PhysicsE_B = Δmc²

Nuclear Binding Energy Calculator

Binding energy from mass defect

Calculate nuclear binding energy from mass defect, or find the mass defect from a known binding energy. Includes energy per nucleon.

Binding energyMass defectPer nucleon
Calculate →
ThermodynamicsP₁V₁/T₁ = P₂V₂/T₂

Combined Gas Law Calculator

Pressure, volume, or temperature

Solve the combined gas law for any of six variables — fill in five values and leave the one you want blank.

PressureVolumeTemperature
Calculate →
Waves & Opticsw = λD/d

Double-Slit Fringe Spacing Calculator

Fringe spacing, wavelength, or slit separation

Calculate the fringe spacing in a double-slit interference pattern, or solve for wavelength or slit separation.

Fringe spacingWavelengthSlit separation
Calculate →
Waves & Opticsn = c/v · θc = sin⁻¹(n₂/n₁)

Refractive Index & Critical Angle Calculator

Refractive index, speed, or critical angle

Calculate refractive index from light's speed in a medium, or find the critical angle for total internal reflection.

Refractive indexSpeedCritical angle
Calculate →
ThermodynamicsQ = mcΔT · Q = mL

Specific Heat & Latent Heat Calculator

Heat for temperature change or phase change

Calculate heat energy for a temperature change, or for a phase change (melting or boiling). Material presets included.

Heat energySpecific heatLatent heatTemperature change
Calculate →
Kinematicsv(A rel B) = vA − vB

Relative Velocity Calculator

1D and 2D relative motion

Calculate the velocity of one object as observed from another, in one dimension or as full 2D vectors.

Relative velocityDirection
Calculate →
ElectromagnetismP = IV = I²R = V²/R

Electrical Power Calculator

Power from current, voltage or resistance

Calculate electrical power from any two of current, voltage, or resistance — all three forms of the power equation.

PowerCurrentVoltageResistance
Calculate →
Waves & Optics1/f = 1/v + 1/u

Lens & Mirror Equation Calculator

Focal length, image distance & magnification

Calculate focal length, image distance, or object distance for any lens or curved mirror, plus magnification.

Focal lengthImage distanceObject distanceMagnification
Calculate →
Classical Mechanicstanθ = v²/(rg)

Banked Curve Calculator

Ideal banking angle, speed or radius

Calculate the ideal banking angle for a curve, the maximum safe speed, or the curve radius — no friction required.

Bank angleSpeedRadius
Calculate →
Classical Mechanicsv_t = √(2mg/ρCdA)

Terminal Velocity Calculator

Terminal speed, mass or area

Calculate the terminal velocity of a falling object, or solve for mass or cross-sectional area.

Terminal velocityMassDrag coefficientArea
Calculate →
Modern Physicsλmax = b/T · P = εσAT⁴

Black-Body Radiation Calculator

Wien's Law & Stefan-Boltzmann Law

Calculate peak emission wavelength (Wien's Law) or total radiated power (Stefan-Boltzmann Law) for any temperature.

Peak wavelengthRadiated powerTemperature
Calculate →
Classical MechanicsR = √(x²+y²)

2D Vector Addition & Resolution Calculator

Add vectors or resolve into components

Add two vectors given their components, or resolve a vector's magnitude and angle into x and y components.

ResultantDirectionComponents
Calculate →
Classical MechanicsJ = FΔt = Δp

Impulse & Momentum Calculator

Impulse, force or time interval

Calculate impulse from force and time, or find the force or time interval for a given change in momentum.

ImpulseForceTimeMomentum change
Calculate →
Modern Physicsc = 299,792,458 m/s

Speed of Light Calculator

mph, miles per second, travel time

Speed of light in miles per second, mph, km/h and m/s — in a vacuum or any medium. Convert any speed to a fraction of c and calculate how long light takes to travel any distance.

Speed of lightFraction of cTravel timeRefractive index
Calculate →
Physics Calculation Tools

Instant physics answers with shown working

Every calculator on this page shows the formula used, substitutes your values step-by-step, and links to the full article explaining the physics. Not just answers — understanding.

What makes a good physics calculator

Most online calculators give you a number and nothing else. Every calculator here shows the equation first, substitutes your exact values, and walks through the arithmetic so you can see exactly how the answer was reached. If you're a student, that shown working is what helps the formula stick.

Each calculator also solves in every direction — not just "give me the output given the inputs." If you know kinetic energy and mass, you can solve for velocity. If you know force and acceleration, you can solve for mass. The triangles work in all directions.

Calculators by topic

Classical Mechanics15 calculators

Projectile Motion, Kinetic Energy, Newton's Second Law, Momentum, Circular Motion, SUVAT, Hooke's Law, Torque, Work & Power, Gravitational PE, Young's Modulus, Banked Curve, Terminal Velocity, Vector Addition, Impulse & Momentum

Waves & Optics7 calculators

Wave Speed, Pendulum Period, Doppler Effect, Snell's Law, Double-Slit Interference, Refractive Index, Lens & Mirror Equation

Electromagnetism8 calculators

Ohm's Law, Coulomb's Law, Resistors in Series & Parallel, Electric Field, Capacitor Energy, Magnetic Force, Faraday's Law, Electrical Power

Thermodynamics4 calculators

Ideal Gas Law, Thermal Expansion, Combined Gas Law, Specific & Latent Heat

Kinematics3 calculators

Free Fall, SUVAT Equations, Relative Velocity

Gravitation3 calculators

Escape Velocity, Gravitational PE, Gravitational Field Strength

Modern Physics6 calculators

Half-Life & Radioactive Decay, Photoelectric Effect, de Broglie Wavelength, Bohr Energy Levels, Nuclear Binding Energy, Black-Body Radiation

Frequently asked questions

Are these calculators free?
Yes — completely free, no account required, no ads. Every calculator on Physics Fundamentals is free to use.
Do you show the working?
Yes. Every calculator shows the formula, substitutes your values, and walks through the arithmetic step by step. You can see exactly how the answer was derived.
Can I solve for any variable?
Yes. Every calculator works in all directions. If you know kinetic energy and velocity, you can solve for mass. If you know force and mass, you can solve for acceleration.
What units do you support?
All calculators support SI units (metres, kilograms, seconds, joules, newtons) as the default. Most also support imperial units and allow switching between common variants (km, cm, miles, etc.).
Can I use these for homework?
Yes — and the step-by-step solutions are specifically designed to help you understand the method, not just get an answer to copy.

Physics Fundamentals

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