🔬 Physics & Chemistry
Free physics and chemistry calculators: forces and motion, springs, gas laws, molarity and pH, half-life and decay, heat transfer and thermal expansion.
Classical mechanics made quick: acceleration and speed–distance–time, gravitational force, friction, torque, Hooke’s law and spring energy, plus Young’s modulus for materials.
Chemistry side: the four gas laws and the ideal combined one, molarity and molecular weight, pH, STP volumes — and nuclear tools for half-life and radioactive decay with named isotopes.
Acceleration Calculator
Calculate acceleration from velocity change over time, or from Newton''s second law (force divided by mass). Get results in m/s², km/h² and g-force.
Boyle's Law Calculator
Calculate pressure or volume changes using Boyle's Law (P₁V₁ = P₂V₂). Enter three known values to instantly find the fourth, with a clear visual of the inverse P–V relationship.
Centripetal Acceleration Calculator
Calculate centripetal acceleration for circular motion from speed or rotation period. Results in m/s², multiples of g and RPM, with the force on a chosen mass.
Charles's Law Calculator
Calculate volume or temperature changes using Charles's Law (V₁/T₁ = V₂/T₂). Enter three known values to instantly find the fourth. Temperature must be in Kelvin.
Combined Gas Law Calculator
Solve the combined gas law P₁V₁/T₁ = P₂V₂/T₂. Enter any five of the six variables (P₁, V₁, T₁, P₂, V₂, T₂) to find the sixth. Temperature must be in Kelvin.
Density Calculator
Calculate density (ρ = m / V) from mass and volume, or reverse-calculate mass or volume from a known density. Includes specific gravity.
Friction Calculator
Calculate friction force using F = μN. Enter coefficient of friction and normal force to find the friction force, or solve for any unknown. Covers both static and kinetic friction.
Gay-Lussac's Law Calculator
Calculate pressure or temperature changes using Gay-Lussac's Law (P₁/T₁ = P₂/T₂). Enter three known values to instantly find the fourth. Temperature must be in Kelvin.
Gravitational Force Calculator
Compute the gravitational attraction between two objects using Newton's law of universal gravitation. Supports Earth, Moon and planetary mass presets with results in newtons, kgf and dynes.
Half-Life Calculator
Calculate the remaining quantity of a radioactive substance using the half-life formula N(t) = N₀ × (1/2)^(t/t½). Enter the initial quantity, half-life and elapsed time to get the remaining amount, decayed amount, decay constant and more.
Heat Transfer Calculator
Calculate conductive heat transfer rate using Q = kAΔT/d. Enter thermal conductivity, surface area, thickness, and temperature difference to find the heat flow in watts.
Helical Spring Calculator
Design a helical compression spring: calculate spring rate from wire diameter, coil diameter and active coils, plus Wahl-corrected shear stress and deflection.
Hooke's Law Calculator
Calculate spring force, spring constant, or displacement using Hooke's Law (F = kx). Enter two known values to find the third, with clear visual of the linear force-extension relationship.
Horsepower Calculator
Calculate horsepower for hydraulic motors, rotating shafts and engines from torque, RPM, flow and pressure. Results in HP and kW with full formulas.
Ideal Gas Law Calculator
Solve the ideal gas equation PV = nRT for any unknown variable. Enter any three of pressure, volume, moles, or temperature and instantly get the fourth, with full unit conversion support.
Molarity Calculator
Calculate molarity (molar concentration, mol/L) from solute mass and solution volume, or calculate the required mass for a target molarity.
Molecular Weight Calculator
Enter a chemical formula like H2O or CaCO3 and get the molecular weight, molar mass and element composition instantly. Runs fully offline.
pH Calculator
Convert between pH and hydrogen ion concentration [H+]. Get pH, pOH, [OH-] and the acid-base classification in one click — fully offline.
Radioactive Decay Calculator
Calculate radioactive decay using N = N₀ × e⁻λᵗ. Enter initial amount, half-life, and elapsed time to find the remaining quantity, or solve for any other variable.
Speed Distance Time Calculator
Solve any speed, distance or time problem by entering two known values. Supports km/h, mph, m/s, km, miles, meters, hours, minutes and seconds. Perfect for physics homework, road trips and running pace calculations.
Spring Potential Energy Calculator
Calculate elastic potential energy stored in a spring using U = ½kx². Enter spring constant and displacement to find stored energy, or solve for any unknown in the equation.
STP Calculator
Calculate gas volumes at Standard Temperature and Pressure (STP). Convert between actual conditions and STP, or find the number of moles using the molar volume of an ideal gas (22.414 L/mol at STP).
Thermal Expansion Calculator
Calculate thermal expansion using ΔL = αL₀ΔT. Enter material coefficient, original length, and temperature change to find the expansion or contraction of metals, plastics, and other materials.
Torque Calculator
Calculate rotational force using τ = r × F. Enter force and lever arm to find torque, or solve for any unknown. Essential for wrenches, motors, levers, and rotational dynamics.
Young's Modulus Calculator
Calculate Young's Modulus (E = σ/ε) from stress and strain, or find any unknown. Enter tensile stress and strain to determine material stiffness, with a built-in reference table.
Frequently asked questions
Which units do the physics tools use?
SI by default with common imperial inputs accepted; each page lists the units it expects so results are never silently mixed.
Are the gas law results exact?
They follow the ideal gas model; deviations at high pressure or low temperature are noted on each page.
Can I calculate decay over a custom time?
Yes — enter any isotope half-life (preset or custom) and elapsed time; remaining fraction and activity update live.