GCSE Maths calculator tips: what you can use and how to use it well
Your calculator is one of the most useful things in the exam hall. It's also one of the easiest ways to lose marks if you don't know it well.
Here's which papers allow one, what the rules say, and how to get the most out of it.
Which papers allow a calculator
GCSE Maths has three papers, each 1 hour 30 minutes and 80 marks. For both Edexcel and AQA:
| Paper | Calculator |
|---|---|
| Paper 1 | No |
| Paper 2 | Yes |
| Paper 3 | Yes |
That means a third of your marks come from a paper where you work everything out by hand. Practise without your calculator as well, or Paper 1 will feel like a different subject. If you're taking a different board, check your own exam timetable.
What the exam boards expect
Many students use a scientific calculator, and that's the sensible choice. Your calculator needs to be allowed in the exam, though, and the rules come from JCQ, the body that sets the regulations the main exam boards follow.
As JCQ's published rules read at the time of checking, a calculator must not have information stored in it that can be retrieved, such as formulae or text. Some calculators have an exam mode, which is only acceptable if it makes the calculator comply. The question paper also says whether calculators are allowed.
These rules are updated, so don't rely on this post alone. Check your own model with your school's exams officer, and look at the exam board's and JCQ's current guidance. Do it well before the exam, not in the last week.
Learn the functions you'll actually use
Every model is laid out differently, so read your calculator's manual or look the keys up online. These are the jobs worth learning.
- Fractions. Most scientific calculators have a fraction key, so you can type a fraction and work with it directly. Use it to check your answers to fraction questions. If a question asks you to show your method, write that down too.
- Powers and roots. Learn the keys for squares, cubes, higher powers and square roots. Put brackets round anything being squared, especially negative numbers.
- Standard form. There's usually a key for entering "times ten to the power". Learn it, because typing it as an ordinary multiplication often goes wrong.
- Brackets. Use them for the top and the bottom of a fraction, like (3 + 4) ÷ (2 + 5). Without them, the calculator follows the order of operations and gives something else.
- Memory and the last answer. Use them to carry a long answer into the next step without rounding in the middle.
Check your answers
Your calculator is great for checking. Before you write an answer down, ask whether it's sensible. A person's height of 17 metres, or a probability of 1.4, is a sign something went wrong. Estimating roughly in your head first, then comparing with the calculator, catches a lot of mistakes.
Common slips
- Rounding too early. Keep the full number in the calculator until the last step.
- Wrong angle mode. For trigonometry, check the calculator is working in degrees unless the question says otherwise.
- Missing brackets. Probably the most common calculator mistake of all.
- Writing the whole display. If the question says "to 2 decimal places" or "3 significant figures", round it.
- Forgetting units. The calculator doesn't write them for you.
- Only writing the answer. Method marks are given for working, even when the final answer is wrong. Write each step down.
- Not having it ready. Use the same calculator all year, and make sure it has working batteries.
Here's my debrief on a calculator paper, which shows where students pick up and lose marks:
And this is a non-calculator paper, to see how the same topics look without one:
Questions people also ask
Can you use a calculator in GCSE Maths?
Yes, on Papers 2 and 3. Paper 1 is non-calculator on both Edexcel and AQA.
What calculator do I need for GCSE Maths?
Many students use a scientific calculator. Your calculator has to be allowed under the JCQ rules and your exam board's rules, so check with your school or exams officer before buying or relying on a particular model.
Do I still need to show working if I use a calculator?
Yes. The mark schemes give method marks for correct working, so if you only write the final answer and it's wrong, there's nothing to give you marks for. Write down the steps you typed in, or the calculation you did.