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Physics equation calculator for GCSE and A-level
Pick a physics equation, enter the values you know with their units, and get the answer with the working set out the way it is marked in exams. Every equation also has practice questions.
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Motion
- v = s / tSpeed, distance and time
- a = Δv / tAcceleration
- v = u + a tFinal velocity
- v2 = u2 + 2a sVelocity squared
- s = u t + ½ a t2Displacement under constant acceleration
- s = ½ (u + v) tDisplacement from average velocity
- p = m vMomentum
- F = Δp / ΔtForce and change in momentum
- F = m v2 / rCentripetal force
- a = v2 / rCentripetal acceleration
- ω = 2πfAngular speed and frequency
- v = ω rSpeed in a circle
Forces
Energy and power
Waves
- v = f λWave speed
- f = 1 / TFrequency and time period
- magnification = image height / object heightMagnification
- n = c / vRefractive index
- n1 sin(θ1) = n2 sin(θ2)Snell’s law
- sin(C) = 1 / nCritical angle
- w = λ D / sDouble-slit fringe spacing
- n λ = d sin(θ)Diffraction grating
- I = P / AIntensity
- I = P / (4πr2)Inverse square law for intensity
Electricity
- Q = I tCharge, current and time
- V = I ROhm’s law
- P = V IElectrical power
- P = I2 RElectrical power
- E = Q VEnergy transferred
- Rtotal = R1 + R2Resistors in series
- 1 / Rtotal = 1 / R1 + 1 / R2Resistors in parallel
- R = ρ L / AResistivity
- ε = V + I rEMF and internal resistance
- Vout = Vin R2 / (R1 + R2)Potential divider
- Vp / Vs = Np / NsTransformer turns ratio
- Vp Ip = Vs IsTransformer power
- C = Q / VCapacitance
- E = ½ C V2Energy stored in a capacitor
- τ = R CTime constant
- V = V0 e−t / τCapacitor discharge
- V = V0 (1 − e−t / τ)Capacitor charging
- F = B I l sin(θ)Force on a current-carrying wire
- ε = N ΔΦ / ΔtInduced emf
Fields and space
- F = Q1 Q2 / (4πε0 r2)Coulomb’s law
- E = V / dUniform electric field
- E = F / QElectric field strength
- E = Q / (4πε0 r2)Field of a point charge
- F = G m1 m2 / r2Newton’s law of gravitation
- g = G M / r2Gravitational field strength
- Vg = −G M / rGravitational potential
- T = 2π√(r3 / (G M))Orbital period
- v = √(2G M / r)Escape velocity
Thermal physics and gases
Nuclear and particles
Oscillations
Materials
Practise with a random question
Press the button for a question with random numbers. Work it out on paper first, then type your answer.
How the calculator works
- Choose an equation from the list above.
- Pick the quantity you want to find. Every other quantity becomes an input.
- Type your values and pick the units they are in. Standard form such as 3e8 or 3 x 10^8 works.
- Read the working underneath. It is set out like a marked answer: equation, rearrangement, substitution, answer.
Common questions
Which equations does this physics calculator cover?
It covers 91 GCSE and A-level physics equations, grouped by topic: motion, forces, energy and power, waves, electricity, thermal physics, nuclear physics, fields and space, oscillations and materials. Check your exam board’s specification and data sheet for the equations you must remember and the ones you are given.
Does the calculator show the working?
Yes. For each calculation it writes the equation, the rearrangement, any unit conversions, the substitution, the calculation and the final answer with units and the number of significant figures you choose.
Can I use it in an exam?
No. It is a revision and homework tool. In exams use the calculator your exam board allows. Use this page to check your own working and to practise.
Is it free to use?
Yes. It is free, with no sign-up, no adverts and no personal tracking.
Looking for a physics formula rather than a calculator? See the formula library, or try the other tools.