My Calculator Stack · Physics formulas

Physics · Formula sheet

Physics formulas

One printable sheet for 49 Physics tools — formulas collected from each calculator’s How it works.

Physics calculators →

Acceleration Calculator

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\[ a = \frac{v_f - v_i}{t} \]

Divide the change in velocity by time.

Angular Resolution Calculator

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\[ \theta = 1.22\,\frac{\lambda}{D} \]

Multiply 1.22 by wavelength and divide by aperture diameter.

Angular Velocity Calculator

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\[ \omega = \frac{\theta}{t} \]

Divide angle in radians by elapsed time.

Aperture Area Calculator

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\[ A = \pi \left(\frac{D}{2}\right)^{2} \]

Use A = π (D/2)².

Bernoulli Equation Calculator

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\[ P_{2}=P_{1}+\tfrac12\rho(v_{1}^{2}-v_{2}^{2})+\rho g(h_{1}-h_{2}) \]

Rearrange to solve for P₂ given P₁, densities, velocities, and heights.

Brewster's Angle Calculator

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\[ \theta_{B} = \arctan\!\left(\frac{n_{2}}{n_{1}}\right) \]

Take the arctangent of the refractive-index ratio.

Buoyancy Calculator

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\[ F_{b} = \rho V g \]

Multiply fluid density, displaced volume, and g.

Capacitance Calculator

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\[ C=Q/V \]

Enter Charge Q (C) and Voltage V for the Capacitance Calculator; use finite values in the indicated domain. The calculator reports C (F): Capacitance relates stored charge to voltage. Voltage must be nonzero when deriving capacitance from charge.

Cylindrical Pipe Flow Rate Calculator

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\[ Q = \pi r^{2} v \]

Compute area from diameter, then multiply by velocity.

Density Calculator

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\[ \rho = \frac{m}{V} \]

Divide mass by volume.

Displacement (distance traveled) Calculator

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\[ s = ut + \tfrac12 at^{2} \]

Combine initial-velocity and acceleration contributions over time.

Drag Equation Calculator

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\[ F_{d} = \tfrac12 \rho v^{2} C_{d} A \]

Combine fluid density, speed squared, drag coefficient, and reference area.

E = mc² Calculator

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\[ E = mc^{2} \]

Multiply mass by c² (c = 299,792,458 m/s).

Electric Power Calculator

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\[ P=VI \]

Enter Voltage (V) and Current (A) for the Electric Power Calculator; use finite values in the indicated domain. The calculator reports Power (W): Electrical power is voltage times current. Voltage and Current must describe the same operating point; AC circuits may also require power factor.

Force Calculator

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\[ F = ma \]

Multiply mass by acceleration.

Free Fall Calculator

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\[ s=\tfrac12 gt^{2},\quad v=gt \]

Distance is half g t squared; speed is g times t.

Frequency Wavelength Calculator

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\[ v=f\lambda \]

Enter Mode (0=f→λ, 1=λ→f), Frequency (Hz), Wavelength (m), and Wave speed (m/s, 0=c) for the Frequency Wavelength Calculator; use only the listed mode or unit codes. The calculator reports Result: v = f λ with speed defaulting to c. Frequency must be positive and Wave speed must use compatible distance/time units.

Friction Calculator

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\[ F = \mu N \]

Multiply μ by normal force.

Froude Number Calculator

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\[ Fr = \frac{v}{\sqrt{gL}} \]

Divide velocity by the square root of g times characteristic length.

Gravitational Force Calculator

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\[ F = G\frac{m_1 m_2}{r^{2}} \]

Use G = 6.6743×10⁻¹¹ N·m²/kg².

Hooke's Law Calculator

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\[ F=kx \]

Enter Spring constant k (N/m) and Displacement x (m) for the Hooke's Law Calculator; use finite values in the indicated domain. The calculator reports Force (N): Hooke's law is linear restoring force for springs. The result applies only within the spring's linear elastic range.

Hydraulic Pressure Calculator

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\[ P = \frac{F}{A} \]

Divide force by area.

Hydraulic Radius Calculator (Full Pipe)

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\[ R_{h} = \frac{D}{4} \]

For a circle, A/P simplifies to D/4.

Hydrostatic Pressure Calculator

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\[ P = \rho g h \]

Multiply density, gravity, and depth.

Ideal Gas Calculator

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\[ PV=nRT \]

Rearrange PV = nRT for the selected variable.

Impulse and Momentum Calculator

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\[ J = Ft = m\Delta v \]

Compute impulse, then Δv = J/m, and add to initial velocity.

Index Of Refraction Calculator

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\[ n = \frac{c}{v} \]

Divide the speed of light by the wave speed in the medium.

Kinetic Energy Calculator

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\[ KE = \tfrac{1}{2}mv^{2} \]

Half the product of mass and velocity squared.

Knudsen Number Calculator

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\[ Kn = \frac{\lambda}{L} \]

Divide mean free path by characteristic length.

Length Contraction Calculator

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\[ L = L_{0}\sqrt{1 - v^{2}/c^{2}} \]

Scale proper length by the Lorentz factor sqrt term.

Lightning Distance Calculator

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\[ d = t\,v_{\text{sound}} \]

Multiply delay by the speed of sound (default 343 m/s).

Mach Number Calculator

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\[ M = \frac{v}{a} \]

Divide object speed by the speed of sound.

Magnitude Of Acceleration Calculator

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\[ |a| = \left|\frac{v_f - v_i}{t}\right| \]

Take the absolute value of Δv / t.

Malus Law Calculator

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\[ I = I_{0}\cos^{2}\theta \]

Multiply incident intensity by cos² of the angle between axes.

Moment Of Inertia Calculator

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\[ I = \tfrac12 m r^{2} \]

Use I = ½ m r² for a uniform solid cylinder or disk.

Newton's Second Law Calculator

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\[ F = ma \]

Multiply mass by acceleration.

Normal Force Calculator

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\[ N = mg\cos\theta \]

Multiply weight by cos of the incline angle.

Ohm's Law Calculator

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\[ V=IR \]

Rearrange V = I R for the unknown.

Period Pendulum Calculator

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\[ T = 2\pi\sqrt{\frac{L}{g}} \]

Take 2π times the square root of length over g.

Poisson's Ratio Calculator

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\[ \nu = -\frac{\varepsilon_{\perp}}{\varepsilon_{\parallel}} \]

Negate the ratio of lateral strain to axial strain.

Potential Energy Calculator

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\[ PE = mgh \]

Multiply mass, gravitational acceleration, and height.

Pressure Calculator

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\[ P = \frac{F}{A} \]

Divide force by area.

Reduced Mass Calculator

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\[ \mu = \frac{m_{1}m_{2}}{m_{1}+m_{2}} \]

Multiply the masses and divide by their sum.

Rotational Kinetic Energy Calculator

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\[ KE = \tfrac{1}{2}I\omega^{2} \]

Half the moment of inertia times angular velocity squared.

Series Parallel Resistance Calculator

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\[ R_s=\sum R_i,\ R_p^{-1}=\sum R_i^{-1} \]

Enter R1 (Ω), R2 (Ω), and R3 (Ω, 0=skip) for the Series Parallel Resistance Calculator; use finite values in the indicated domain. The calculator reports Series (Ω) and Parallel (Ω): Series adds; parallel uses reciprocal sum. Resistances should be nonnegative, and zero-ohm parallel branches need special handling.

Strain Calculator

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\[ \varepsilon = \frac{\Delta L}{L_{0}} \]

Divide change in length by original length.

Stress Calculator

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\[ \sigma = \frac{F}{A} \]

Divide applied force by cross-sectional area.

Velocity Calculator

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\[ v = \frac{d}{t} \]

Divide distance by time.

Work Calculator

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\[ W = Fd\cos\theta \]

Multiply force, distance, and cos of the angle between them.

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