Free physics calculators for motion, forces, energy and momentum. Each tool shows the formula, the units and a worked example alongside the answer, so you can check the result instead of trusting a black box. Everything runs in your browser with no signup.
Motion in one and two dimensions: projectiles, free fall, momentum and friction.
Acceleration from a change in velocity over time.
Estimate arrow speed from the drop over a known distance.
Compute the mass-over-area term that governs drag deceleration.
Projectile range for a car launched from a ramp.
Final velocities for a two-body collision with restitution.
Find displacement from positions or from steady velocity.
Time, speed and distance for an object dropped from rest.
Speed and distance when drag grows with the square of speed.
Static and kinetic friction force on flat and inclined surfaces.
Combine airspeed and wind into a ground speed.
Range, time and impact speed for a horizontal launch.
Convert between force, time, impulse and velocity change.
Acceleration and forces for a mass sliding down a ramp.
Peak height of a projectile launched at an angle.
Convert minute-of-angle adjustments into spread at a distance.
Momentum and kinetic energy from mass and velocity.
Muzzle speed from a ballistic pendulum rise.
Torsional resistance of solid and hollow circular sections.
Range, peak height and flight time for an angled launch.
Flat-ground range from launch speed and angle.
Estimate drag-strip elapsed time and trap speed from power and weight.
Add two velocities into one resultant vector.
Rolling resistance force and power for a moving wheeled load.
Speed at the bottom of a sledding slope.
Solve the five constant-acceleration equations of motion.
The steady fall speed where drag balances weight.
Air time for a projectile launched and landing at the same height.
Height of a projectile at any horizontal distance.
Average velocity from displacement and time.
Forces and the motion they cause: Newton's laws, drag, thrust and gravity.
Find the scale reading when a lift accelerates up or down.
The speed a banked curve is designed to handle.
Force, speed or radius for motion in a circle.
Bounciness from drop and rebound height.
Aerodynamic drag from speed, area and drag coefficient.
Find force, mass or acceleration from Newton's second law.
Newton's law of gravitation between two masses.
Average force in a fall, a car crash or any sudden stop.
Add two forces at an angle and get the resultant magnitude and direction.
Find the support force on a flat surface or an incline.
Delta-v, mass ratio and propellant mass for a rocket burn.
Tension in a hanging rope or in an Atwood pulley system.
Thrust from exhaust mass flow, velocity and nozzle pressure.
Convert between mass and weight at any gravitational acceleration.
Objects at rest: torque, balance, pressure and structural reactions.
Support reactions for a simply supported beam with a point load.
Balance point of up to three masses along a line.
Spring force, spring constant or extension.
Force multiplication from two piston diameters.
Pressure at depth in a liquid, gauge and absolute.
Pressure, force or contact area from P = F/A.
Balance a lever with unequal masses or distances.
Turning effect of a force about a pivot.
Energy storage and transfer: work, kinetic and potential energy, power and efficiency.
Useful output as a percentage of energy input.
Energy stored in a stretched or compressed spring.
Energy of motion from mass and speed.
Total kinetic plus potential energy of an object.
Gravitational energy from mass and height.
Power from work and time, or from force and speed.
Distance needed to stop from a given speed.
Work done by a force at an angle to the motion.
Energy dissipated by sliding friction over a distance.
Spinning, rolling and oscillation: angular kinematics, inertia, momentum and springs.
Rate of change of angular velocity.
Spin momentum from inertia and angular velocity.
Angular speed from angle turned and time taken.
Time for one orbit from radius and speed.
Final spin after the moment of inertia changes.
Rotational inertia for common shapes about a standard axis.
Period of a real rigid body swinging about a pivot.
Total energy of a rolling hoop, cylinder or sphere.
Linear speed, angular speed or radius for rolling without slipping.
Energy stored in a spinning object.
Angular velocity and angle under constant angular acceleration.
Power delivered by a torque at an angular speed.
Acceleration of a harmonic oscillator at time t.
Position in simple harmonic motion at a given time.
Velocity of a simple harmonic oscillator at time t.
Period from length, or length from period.
Oscillation period of a mass on a spring.
Force multipliers: levers, pulleys, screws and gears, and the mechanical advantage behind them.
Output speed and torque from gear tooth counts.
Balance effort and load on a lever.
Force multiplication from load and effort.
Effort and load for a block-and-tackle with n supporting ropes.
Force multiplication from handle radius and thread pitch.
Force multiplication from wedge length and thickness.
Force multiplication from wheel and axle radii.
Reflection, refraction, lenses and instruments, plus interference, diffraction and photometry.
Colour spread from a thin prism.
Angle at which reflected light is fully polarised.
Exposure value from aperture, shutter speed and ISO.
Distance over which light remains coherent.
Angle beyond which total internal reflection occurs.
Near and far sharp limits for a focus distance.
Diffraction angle from groove spacing and wavelength.
Fringe spacing from wavelength, slit separation and screen distance.
Angle covered by a lens and sensor.
Focus distance that maximises depth of field.
Lux from luminous flux, area or intensity and distance.
Reflected angle from the angle of incidence.
Total power of thin lenses in contact.
Focal length from lens curvature and refractive index.
Optical power in dioptres from focal length.
Frequency, wavelength and photon energy of light.
Flux from intensity and solid angle.
Image size and orientation from distances or heights.
Angular magnification of a simple magnifier.
Transmitted intensity through a polarising filter.
Total magnification from tube length and lens focal lengths.
Image distance for a curved mirror.
Focal length from the radius of curvature.
Light-gathering cone of a fibre or microscope objective.
Effective optical distance through a medium.
Ray deviation through a triangular prism.
Refractive index from the speed of light in a medium.
Position of the first dark fringe behind a slit.
Angle of refraction at a boundary between two media.
Angular magnification from objective and eyepiece focal lengths.
Film thickness for constructive or destructive reflection.
Image distance for a converging or diverging lens.
Sound speed, decibels, Doppler shift, musical strings, pipes, rooms and absorption.
Characteristic impedance from density and sound speed.
Difference frequency heard when two tones nearly match.
Combine uncorrelated sound levels and identical sources.
Observed frequency for a moving source or listener.
Level change with distance in a free field.
Convert between flow speed, sound speed and Mach number.
Standing-wave frequencies for open and closed pipes.
Low-frequency axial resonances of a rectangular room.
Sabine reverberation time from room volume and absorption.
Acoustic power per unit area from a point source.
Decibels from acoustic intensity, and the inverse.
Decibels of acoustic power relative to 1 pW.
Convert acoustic pressure to dB SPL and back.
Sound speed in air, an ideal gas, or from an echo delay.
Harmonic frequencies of a stretched string.
Wavelength, frequency and speed of a sound wave.
Stress, strain and material behaviour: elastic moduli, thermal expansion, density and pressure-vessel stress.
Normal stress from force and area.
Deformation per unit length.
Elastic modulus in tension/compression.
Modulus of rigidity for shear deformation.
Modulus for uniform compression.
Negative ratio of transverse to axial strain.
Change in length from temperature change.
Change in volume from temperature change.
Mass per unit volume.
Ratio of a material's density to the density of water.
Engineering stress, strain and tangent modulus.
True stress from engineering stress and strain.
Logarithmic strain from engineering strain.
Contact stress between two cylinders or a cylinder and a flat.
Critical load for column buckling.
Non‑dimensional parameter for column stability.
Hoop stress in a pressurized cylindrical vessel.
Longitudinal stress in a pressurized cylindrical vessel.
Membrane stress in a thin-walled spherical vessel under pressure.
ASME B31.3 approximate wall thickness from pressure and allowable stress.