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Physics Fundamentals

Physics
Calculators.

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 & OpticsThermodynamicsElectromagnetism
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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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 →
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 Mechanics10 calculators

Projectile Motion, Kinetic Energy, Newton's Second Law, Momentum, Circular Motion, SUVAT, Hooke's Law, Torque, Work & Power, Gravitational PE

Waves & Optics4 calculators

Wave Speed, Pendulum Period, Doppler Effect, Snell's Law

Electromagnetism1 calculators

Ohm's Law

Thermodynamics2 calculators

Ideal Gas Law, Thermal Expansion

Kinematics2 calculators

Free Fall, SUVAT Equations

Gravitation2 calculators

Escape Velocity, Gravitational PE

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.