Fiducia TogetherSignificant figures in science
How many digits your answer is allowed to claim. Marks are dropped here constantly.
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.
What it is
Your answer should be given to the same number of significant figures as the least precise measurement it came from — usually two or three at GCSE.
Where it applies
All three sciences and maths.
How it works
A calculator produces ten digits. Data measured with a ruler to the nearest millimetre does not support ten digits, and writing them claims a precision that does not exist.
This is the same idea as significant figures in maths, applied to measurement.
How to use it in your work
Do the rounding at the END of the calculation only.
If the question gives data to 2 s.f., give the answer to 2 s.f. unless told otherwise.
Units are marks. An answer with no unit, or the wrong one, generally scores nothing however correct the number.
Where to get help
Your teacher, your board's specification for the depth required at your tier, and Bitesize for the diagrams. The subject song runs the topics in order.
Where to read more
Last reviewed 2026-08-28 by Fiducia Together · Next review due 2027-08-28
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.