The Physics Formula Searcher is a free reference and calculator covering more than 170 formulas across classical mechanics, thermodynamics, electromagnetism, optics, waves, modern physics, nuclear physics, and astrophysics. Unlike a static formula sheet, it is organized around the physical quantities themselves: type the name of a variable — such as velocity, force, energy, charge, or wavelength — and instantly see every equation that contains it.
Start typing in the search box. Searching displacement returns every kinematics and energy equation that includes displacement, with the matching variable highlighted. You can also click any variable chip beneath a formula to jump to all the formulas that share that quantity.
Enable Search by symbol to look things up by their mathematical symbol instead of their name. Typing λ finds wavelength and decay-constant formulas; typing v matches velocity in all its forms, including subscripted variants like v₀ and v_d.
Turn on Show calculators and most formulas gain a calculator. Enter the values you know, leave exactly one field blank, and press Solve — the tool rearranges the equation and computes the unknown. Fundamental constants such as the speed of light, the gravitational constant, and Planck's constant are pre-filled automatically.
Each calculator input has a unit menu. Enter a speed in km/h, a mass in grams, an energy in electron-volts, or an angle in degrees, and the calculator converts to SI units before solving, then returns the answer in the unit you choose.
The entire interface — including category names, variable names, and formula names — is available in English, Spanish, French, German, and Chinese. Search works in your selected language too.
Yes. The Physics Formula Searcher is completely free to use for students, teachers, and anyone studying physics.
The calculators use the exact algebraic rearrangement of each formula and standard values for physical constants. As with any tool, always double-check critical results and mind significant figures.
A small number of relations — such as vector sums, derivative definitions, and equations with several interdependent unknowns — are shown for reference but do not include a calculator.
Traditional formula sheets are organized by chapter, which is fine if you already know which equation you need. But studying and problem-solving usually works the other way around: you know the quantities in front of you — maybe a mass, a velocity, and a time — and you need to find the equation that connects them. Searching by variable mirrors how you actually think through a problem. Type what you have, and every relevant equation appears at once, across every topic, so you can spot the one that fits. It also reveals connections students often miss — for example, that displacement shows up not only in the kinematics equations but also in work, elastic potential energy, and simple harmonic motion.
A car accelerates from rest at 3 m/s² for 5 seconds. Search velocity, open the calculator on v = u + a·t, enter initial velocity u = 0, acceleration a = 3, and time t = 5, then Solve for v. The result is 15 m/s. Because you can leave any field blank, the same calculator also lets you work backwards — for instance, find how long it takes to reach a target speed.
Suppose a current is given as 250 mA and a resistance as 4.7 kΩ, and you want the voltage. Search Ohm, open the calculator on V = I·R, type 250 and switch its unit to mA, type 4.7 and switch to kΩ, then Solve. The tool converts both inputs to SI before computing, so you get the correct voltage without doing the conversions by hand.
Kinetic energy is 90 J and speed is 6 m/s; what is the mass? Search kinetic energy, open KE = ½·m·v², enter KE = 90 and v = 6, leave m blank, and Solve. The calculator rearranges the equation for you and returns 5 kg.
momentum) to see every equation it appears in — a fast way to build a mental map.Yes. The coverage spans introductory and intermediate physics, including the topics found in AP Physics 1 & 2, IB Physics, A-Level, and first-year university courses — kinematics, dynamics, energy, electricity, magnetism, thermodynamics, waves, optics, and modern physics.
Yes. The layout adapts to phones and tablets, and because it's a single lightweight page it loads quickly and even works offline once cached.