GCSE Physics Equations: The Complete List You Need to Memorise

GCSE Physics equations can feel like a foreign language at first — a jumble of letters, symbols, and units that you’re expected to memorise and apply under exam pressure. The good news? There’s a manageable number of them. With the right approach, they become second nature.

You need to know which equations you must memorise and which ones are given in the exam. This varies by exam board, so check your specification carefully. This guide focuses on the core equations that appear across AQA, Edexcel, and OCR.

Equations You Must Memorise

These don’t appear on formula sheets, so they need to be locked into your memory:

Energy and Power

Kinetic energy = 0.5 × mass × speed² KE = ½mv²

Gravitational potential energy = mass × gravitational field strength × height GPE = mgh

Power = energy transferred ÷ time or Power = work done ÷ time P = E/t or P = W/t

Work done = force × distance W = Fs

Efficiency = useful energy output ÷ total energy input (×100 for percentage)

Forces and Motion

Weight = mass × gravitational field strength W = mg

Force = mass × acceleration F = ma

Momentum = mass × velocity p = mv

Acceleration = change in velocity ÷ time a = Δv/t

Electricity

Charge = current × time Q = It

Potential difference = current × resistance V = IR (Ohm’s Law)

Power = potential difference × current or Power = current² × resistance P = VI or P = I²R

Energy transferred = power × time or Energy = charge × potential difference E = Pt or E = QV

Waves

Wave speed = frequency × wavelength v = fλ

Period = 1 ÷ frequency T = 1/f

Density and Pressure

Density = mass ÷ volume ρ = m/V

Pressure = force ÷ area P = F/A

Equations Given in the Exam

These typically appear on your formula sheet, but you still need to know when and how to use them:

Energy

Elastic potential energy = 0.5 × spring constant × extension²
Change in thermal energy = mass × specific heat capacity × temperature change

Forces

Force applied to a spring = spring constant × extension
Moment of a force = force × distance from pivot

Atomic Physics

Activity = number of decays ÷ time
Half-life calculations (various forms)

Space and Gravity

Orbital speed formulas
Red-shift equations

Check your exam board’s equation sheet so you know exactly what will be provided. You can also find neatly organised versions on our formula sheets page.

Tips for Memorising Equations

1. Understand, Don’t Just Memorise

Memorising “F equals ma” is harder than understanding “the force needed to accelerate an object depends on its mass and how fast you want to accelerate it.” Once you understand what an equation represents, it sticks.

A consistent pattern in physics: the students who struggle most are the ones who memorise without understanding. They can recite the formula but freeze the moment a question looks slightly different from the textbook example.

2. Use Triangle Methods for Simple Rearrangements

For equations like v = fλ or V = IR, the triangle method works well.

Put the top variable (v or V) at the top of a triangle, and the two bottom variables (f and λ, or I and R) at the bottom. Cover the variable you want to find, and what remains shows you the calculation.

3. Create Flashcards

Write the equation name on one side, the formula on the other. Include:

The formula itself
What each symbol means
The units for each quantity
When you’d use this equation

Test yourself regularly. Not just the night before.

4. Use Mnemonics

Some students create memory aids:

V = IR: “Vampire Is Ridiculous”
P = VI: “Please Vote Independence”
W = Fs: “Work For Success”

They’re silly, but if they help you remember, use them.

5. Practice, Practice, Practice

You can know every equation perfectly, but if you can’t apply them to questions, you won’t score marks. Past papers are essential. Look for:

Which equations the question requires
What information you’re given
What units you need to convert
How to rearrange the equation

6. Learn the Units

Every quantity has units. For example:

Energy: joules (J)
Power: watts (W)
Force: newtons (N)
Mass: kilograms (kg)
Distance/height: metres (m)
Time: seconds (s)
Current: amperes (A)
Potential difference: volts (V)
Resistance: ohms (Ω)

Knowing units helps you check if your answer makes sense.

Common Mistakes and How to Avoid Them

The most common mistake in mock energy questions: Students write KE = mv² and forget both the ½ AND the squaring, calculating mv instead of ½mv². It’s not unusual to see this single error account for 30–40% of dropped marks across an energy section. The fix is procedural: write the equation first, every single time, and check you’ve included every part before substituting numbers.

Using the wrong units. If the question gives mass in grams but your equation needs kilograms, you must convert. Always check units before calculating.

Not showing your working. Even if your final answer is wrong, you can still earn method marks by showing you selected the correct equation and substituted values properly.

Rearranging incorrectly. If you need to find mass from F = ma, rearrange to m = F/a before substituting numbers. Don’t try to calculate with numbers in the wrong places.

Using calculator incorrectly. When squaring or dividing, use brackets to ensure the calculator follows the correct order of operations.

How to Structure Calculation Questions

Follow these steps for every calculation question:

Write down the equation you’re using
Substitute the numbers with units
Show your calculation step-by-step
Write your answer with the correct unit

For example:

Question: Calculate the kinetic energy of a car with mass 1000 kg travelling at 20 m/s.

KE = ½mv²

KE = ½ × 1000 × 20²

KE = 0.5 × 1000 × 400

KE = 200,000 J or 200 kJ

This method earns you marks even if you make a small arithmetic error.

Topic-Specific Equation Clusters

Energy Topic

When revising energy, learn the whole cluster together: KE, GPE, work done, power, and efficiency. Many questions require multiple equations in sequence.

A useful mental model for students who freeze on multi-equation energy questions: treat it like a chain. Energy transfers from one form to another, and each transfer has its own equation. Work out which forms are involved, then pick the matching equations one transfer at a time.

Electricity Topic

Ohm’s Law (V = IR) links to power equations. Practice questions that require you to use V = IR to find current, then P = VI to calculate power.

Waves Topic

Wave speed equations appear in almost every waves question. Combine with frequency and wavelength knowledge to solve problems about sound, light, and electromagnetic waves.

Foundation vs Higher Tier

Foundation Tier students need fewer equations and simpler calculations. Higher Tier includes more complex rearrangements and multi-step problems.

If you’re on the Foundation/Higher borderline, master the Foundation equations perfectly before worrying about Higher-only content.

Week Before the Exam

Create a one-page “equation dump sheet” with all the equations you need to memorise. Test yourself by covering the equations and writing them from memory. Do this daily in the final week.

On exam morning, don’t try to learn new equations. Just review your sheet once to refresh your memory.

In the Exam

If you can’t remember an equation, don’t panic. Look at the units in the question — they often give clues. If you’re calculating energy (joules) and you’re given mass (kg) and height (m), that points toward GPE = mgh.

Read the question carefully. It often tells you which formula to use: “Calculate the momentum…” immediately tells you to use p = mv.

A persistent confusion under exam conditions: students mix up weight and mass. Weight is a force (newtons). Mass is measured in kilograms. If a question asks for weight, you need W = mg. If it gives you weight and asks for mass, rearrange to m = W/g.

The Bottom Line

Physics equations are the foundation of your calculations grade. You can’t escape them, so embrace them. With regular practice and active revision, they become automatic.

Don’t wait until the last minute. Start memorising now, practice weekly, and by exam day these equations will feel as natural as knowing your times tables.

How to Use This Guide

Print off the “Equations You Must Memorise” section and stick it somewhere you’ll see daily — your bedroom wall, inside your planner, wherever works. Test yourself on five equations each morning before school. When you get one wrong, that’s your focus for the day. Once you’re confident with recall, move on to past paper questions and practice applying them. I’d suggest our formula sheets page as your next stop, then straight into timed questions.

UpGrades provides targeted equation practice with step-by-step worked solutions, helping you not just memorise formulas but understand exactly how to apply them in different question types.