AnyTool
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How do I solve a physics formula for any variable?

Pick a category in AnyTool Physics Calculator (kinematics, forces, energy, power, momentum, circular motion, waves, electricity, density/pressure or gravitation), choose a formula such as v = u + a·t or F = m·a, then tap the variable you want to find and leave it blank. Fill in the other quantities in SI units and the tool rearranges the formula algebraically for your unknown — for example v = u + a·t becomes a = (v − u) / t — then shows the rearranged formula, the substitution with your numbers, and the result, live in your browser.

  • Solve any formula for any of its variables — the algebra is done for you
  • Kinematics, Newton’s laws, energy, power, momentum, circular, waves, electricity, gravitation
  • Shows the rearranged formula and the substitution line, not just a number
  • Constants g, G, c and k are built in; impossible inputs flagged honestly
  • 100% in your browser — no upload, no signup, works offline

What is

Physics Calculator

A physics calculator is a multi-formula solver that takes a standard physics equation — such as Newton’s second law F = m·a, the kinematics equation v² = u² + 2·a·s, kinetic energy KE = ½·m·v², Ohm’s law V = I·R or Newton’s law of gravitation F = G·m₁·m₂/r² — and rearranges it to make any one variable the subject, then substitutes the known values to compute that unknown. It relies on the SI system of units and on idealised assumptions (no friction or air resistance unless those terms are in the equation).

Calculators

Related terms

Kinematics equationsNewton’s second lawOhm’s lawKinetic energySI units

Frequently Asked Questions

Rearrange to a = (v − u) / t: subtract the initial velocity from the final velocity and divide by the time.

The kinematics equation v = u + a·t rearranges to a = (v − u) / t. So acceleration equals the change in velocity (final minus initial) divided by the time taken. In AnyTool Physics Calculator you choose this formula, tap a as the unknown, enter v, u and t in SI units (m/s and seconds), and it shows the rearranged formula, the substitution with your numbers, and the answer in m/s² — all computed in your browser.

Kinematics, Newton’s laws and weight, energy and work, power, momentum and impulse, circular motion, waves, electricity (Ohm’s law and power) density and pressure, and gravitation.

AnyTool Physics Calculator covers more than two dozen common formulas grouped by topic: kinematics (v = u + a·t, s = u·t + ½a·t², v² = u² + 2·a·s, s = ½(u + v)·t), forces (F = m·a, weight W = m·g), energy and work (KE = ½m·v², PE = m·g·h, W = F·d·cosθ), power (P = W/t, P = F·v), momentum and impulse (p = m·v, J = F·Δt), circular motion (a = v²/r, F = m·v²/r), waves (v = f·λ, T = 1/f), electricity (V = I·R, P = V·I, P = I²·R), density and pressure (ρ = m/V, P = F/A), and Newton’s law of gravitation (F = G·m₁·m₂/r²). Each can be solved for any of its variables.

It expects consistent SI units and does not convert for you, and it assumes ideal conditions — no friction or air resistance unless those terms are in the equation.

The calculator computes on the numbers you enter, so you must supply consistent SI units — metres, kilograms, seconds, newtons, joules, and so on — because it does not convert centimetres to metres or grams to kilograms for you. It also evaluates idealised formulas that assume no friction, drag or air resistance, point masses and uniform fields, unless a quantity is explicitly part of the equation. It is candid about both limits so you check your assumptions and units before trusting the answer.

Yes. It is free with no signup and runs entirely in your browser, so the values you enter never leave your device and it works offline.

AnyTool Physics Calculator is completely free with no account, and every calculation runs in your browser on a small, unit-tested engine, so nothing you type is uploaded and the page keeps working offline after first load. Where a rearrangement involves a square root, a division, or an inverse trig function, impossible inputs (a negative radicand, a zero divisor, or a cosine out of range) are reported as “no real solution” rather than silently producing NaN.

Detailed Explanation

Methodology

How the Physics Calculator Solves for Any Variable

Each formula is stored with its variables and a solver that knows how to isolate every one of them. When you pick a target variable, the engine selects the rearranged form algebraically — for example v = u + a·t becomes a = (v − u) / t or t = (v − u) / a — substitutes the known values, and returns the result along with the rearranged formula and a substitution line. The displacement-versus-time case s = u·t + ½a·t² is solved for time as a quadratic, choosing the smallest non-negative root, and every rearrangement guards against division by zero, negative radicands and out-of-range inverse-trig arguments. All routines are pure functions in a unit-testable engine.

  • Every variable of every formula has an explicit closed-form rearrangement
  • Kinematics, forces, energy, power, momentum, circular, waves, electricity, fluids, gravitation
  • Solving s = u·t + ½a·t² for t uses the quadratic formula (smallest non-negative root)
  • Constants g = 9.80665, G = 6.6743e−11, c and k are built in
  • Pure, unit-testable engine — no DOM, no server
How It Works

Formulas, Rearrangement and Substitution Shown

More than two dozen formulas are grouped into ten topics, and a result-first card shows the chosen equation, the solved value with its unit, and a three-line working — rearrange, substitute, result — so the answer is auditable rather than opaque. You tap which symbol is unknown, leave that field blank, and fill the rest; the page solves live as you type. The copy button exports the formula, substitution and answer as text.

  • Solve for any variable by tapping its symbol and leaving it blank
  • Rearranged formula and substitution line shown for every answer
  • Live recompute as you type; one-tap copy of the full working
  • Per-field SI units displayed so you know what to enter
  • Ten topics from kinematics to gravitation in one tool
Limitations

Ideal Conditions and SI Units

These are idealised single-equation formulas: they assume no friction, drag or air resistance, point masses and uniform fields unless a term for them appears in the equation, so the user must check those assumptions. The tool expects consistent SI units and does not convert between them, and it uses IEEE-754 double precision, so extreme inputs can round. It is a formula solver, not a simulator or a computer-algebra system.

  • Idealised formulas — no friction or air resistance unless modelled
  • Consistent SI units expected; no automatic unit conversion
  • Single-equation solver, not a multi-body simulator or CAS
  • Impossible inputs (negative root, zero divisor) flagged, not NaN
  • Double-precision arithmetic can round on extreme inputs
Privacy & Security

Privacy and Offline Use

All solving runs in the browser as pure functions, so nothing you enter is sent to a server, there is no account or tracking, and the page keeps working offline after first load. The values you type live only in the page and reset on reload.

Physics formula solving: in-browser (AnyTool) vs typical online calculators
CapabilityAnyToolTypical online calculators
Where it runs100% in your browser, offline-capableOften server-side
Solve for any variableYes, every variable of every formulaOften one fixed output
Working shownRearranged formula + substitutionUsually just a number
Formula coverage25+ across ten topics in one toolOften one formula per page
Edge casesNegative root / zero divisor flaggedMay show NaN or wrong value
PrivacyNothing uploaded, no accountMay log inputs

AnyTool rearranges and evaluates each formula locally with a stable, unit-tested engine and uploads nothing.