Physics Calculators
22 tools in this collection — free, instant, and private in your browser.
Physics calculators give you instant, formula-driven answers to the equations that describe how the physical world behaves. Whether you are a student working through a textbook problem, an engineer verifying a quick estimate, or a curious learner who wants to see a concept in action, these tools let you skip the arithmetic and focus on understanding the result.
The tools in this category span classical mechanics, waves, thermodynamics, electrostatics, and fluid dynamics. Tools like the Force Calculator (F = ma), Kinetic Energy Calculator, and Potential Energy Calculator cover the core of Newtonian mechanics and are a natural starting point. If you are studying oscillatory or wave phenomena, the Pendulum Period Calculator, Sine Wave Calculator, and Doppler Shift Calculator let you explore frequency, amplitude, and period interactively.
Several tools handle more specialised scenarios. The Projectile Motion Calculator and Projectile Range Calculator both deal with objects launched at an angle, but the Range tool is optimised for quickly finding the horizontal distance while the Motion tool gives a fuller breakdown of the trajectory at any point in time. Similarly, the Escape Velocity Calculator is useful for astronomy and rocketry contexts, whereas the Altitude Pressure Calculator suits aviation and meteorology questions.
For electrostatics, the Coulomb's Law Calculator quantifies the force between charged objects. For fluid mechanics, the Reynolds Number Calculator classifies flow as laminar or turbulent. For radioactive decay, the Half-Life Calculator handles exponential decay problems. The Snell's Law Calculator covers refraction at optical boundaries, and the Hooke's Law Spring Force Calculator links spring displacement to restoring force.
When choosing a tool, match it to the variables you already know. Each calculator lists its input fields clearly, so identify your knowns first, then pick the tool whose inputs align with the information you have on hand.
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| Tool | What it does |
|---|---|
| Altitude Pressure Calculator | Calculate atmospheric pressure at any altitude using the international barometric formula. Useful for aviation, hiking, and altitude sickness planning. |
| Coulomb's Law Calculator | Calculate the electrostatic force between two point charges using Coulomb's law: F = kq₁q₂/r². Enter the two charges (C) and separation distance (m). |
| Density Calculator (ρ = m/V) | Calculate density, mass or volume using ρ = m/V. Enter any two of density, mass and volume to find the third. Includes specific gravity vs water. |
| Doppler Shift Calculator | Calculate the observed frequency due to the Doppler effect. Enter source frequency, source velocity, observer velocity and wave speed. Positive source velocity = source moving away; positive observer velocity = moving toward. |
| Escape Velocity Calculator | Calculate the escape velocity of any celestial body using v_e = √(2GM/R). Enter mass (kg) and radius (m). Earth's escape velocity is ~11,186 m/s. |
| Force Calculator (F = ma) | Calculate force using Newton's second law F = ma. Enter mass (kg) and acceleration (m/s²) to get force in Newtons, plus the object's weight on Earth. |
| Half-Life Calculator | Calculate radioactive or exponential decay using half-life. Enter the initial amount, half-life and elapsed time to get remaining amount, fraction left, number of half-lives and a chart. |
| Kinetic Energy Calculator | Calculate kinetic energy KE = ½mv² and momentum p = mv. Enter mass (kg) and speed (m/s) for instant results in Joules. |
| Pendulum Period Calculator | Calculate the period of a simple pendulum: T = 2π√(L/g). Enter pendulum length and gravity. Includes a large-angle correction for amplitudes above 10°. |
| Potential Energy Calculator (PE = mgh) | Calculate gravitational potential energy PE = mgh. Enter mass, gravitational acceleration and height to get potential energy in Joules. |
| Power Calculator (P = W/t) | Calculate mechanical power in Watts and horsepower. Enter work done and time, or force and distance (at constant speed) and time. |
| Projectile Motion Calculator | Calculate projectile motion: range, max height, time of flight and a trajectory chart. Enter launch velocity, angle, initial height and gravity. |
| Projectile Range Calculator | Calculate the horizontal range, maximum height and time of flight of a projectile launched from flat ground using R = v₀²sin(2θ)/g. Distinct from the trajectory plotter — this gives numerical answers only. |
| Reynolds Number Calculator | Calculate the Reynolds number Re = ρvL/μ to determine whether fluid flow is laminar, transitional or turbulent. Enter fluid density, velocity, characteristic length and dynamic viscosity. |
| Sample Rate & Nyquist Calculator | Calculate the Nyquist frequency (maximum reproducible frequency) for any audio sample rate. The Nyquist limit is exactly half the sample rate. |
| Sine Wave Calculator & Plotter | Plot a sine wave y = A·sin(2πft + φ). Enter amplitude, frequency and phase to see the waveform, period, angular frequency and RMS value. |
| Snell's Law Calculator | Calculate the angle of refraction using Snell's law: n₁sinθ₁ = n₂sinθ₂. Enter the refractive indices and angle of incidence. Detects total internal reflection and calculates the critical angle. |
| Speed, Distance & Time Calculator | Solve for speed, distance or time using the formula distance = speed × time. Enter any two values to find the third instantly. |
| Terminal Velocity Calculator | Calculate terminal velocity using the drag equation: v_t = √(2mg / ρC_dA). Enter mass, gravity, drag coefficient, fluid density and cross-section area. |
| Thin Lens Equation Calculator | Solve the thin lens equation 1/f = 1/dₒ + 1/dᵢ for any unknown. Enter two of focal length, object distance and image distance (in cm) to find the third, magnification and image type. |
| Wavelength & Frequency Calculator (c = fλ) | Calculate wavelength, frequency and photon energy of light using c = fλ. Enter wavelength in metres or frequency in Hz to find the other. |
| Work Calculator (W = Fd·cosθ) | Calculate mechanical work done W = F·d·cos(θ). Enter force, distance and angle between force and displacement to get work in Joules. |
Frequently asked questions
- Do these calculators show the formula they use?
- Yes. Each physics calculator displays the relevant equation alongside the result so you can see exactly how the answer was derived and use it as a learning reference.
- What units should I use when entering values?
- The calculators use SI units by default (metres, kilograms, seconds, newtons, joules). Input fields are labelled with the expected unit, and some tools offer unit selectors for common alternatives such as feet or miles.
- What is the difference between the Projectile Motion Calculator and the Projectile Range Calculator?
- The Projectile Motion Calculator gives you the full trajectory, including height, velocity components, and time of flight at any point. The Projectile Range Calculator is a faster single-output tool focused solely on the maximum horizontal distance the projectile travels.