AQA · GCSE · Computer Science
Course version: 8525 · Version from Sept 2020
Units of information: tera, 1 TB is 1,000 Gigabytes.
The prefix tera (symbol T) multiplies a unit by 10¹², and in this specification the byte prefixes are decimal, so 1 terabyte (1 TB) equals 1,000 gigabytes (1,000 GB).
Checked against the AQA 8525 specification (opens in a new tab) on .
- Point 11 of 12
Study notes
From the checked teaching notes for this specification point.
The idea
The prefix tera (symbol T) multiplies a unit by 10¹², and in this specification the byte prefixes are decimal, so 1 terabyte (1 TB) equals 1,000 gigabytes (1,000 GB). Work from the prefix table: kilo = 10³, mega = 10⁶, giga = 10⁹, tera = 10¹². Because each step up is a factor of 1,000, converting GB to TB means dividing by 1,000, so 4,000 GB = 4 TB and 250 GB = 0.25 TB. Converting the other way means multiplying by 1,000, so 2 TB = 2,000 GB. A useful check is that the number of terabytes must always be smaller than the number of gigabytes for the same storage. Keep the decimal relationship consistent: do not mix in the binary 1,024 factor, which belongs to a different counting convention and is not what this statement describes.
What earns the marks
- Tera is represented by the symbol T and means 10¹² of the base unit.
- 1 TB = 1,000 GB because giga is 10⁹ and tera is 10¹², a difference of a factor of 1,000.
- Converting GB to TB divides the number by 1,000; converting TB to GB multiplies by 1,000.
- The decimal prefix relationship is used here, so the factor between adjacent prefixes is 1,000, not 1,024.
- Applying the conversion correctly to a value, for example 3,500 GB = 3.5 TB.
Common mistakes and how to put them right
Using 1,024 as the factor between GB and TB.
Put it right: The specification's prefix table is decimal, so the factor is 1,000.
Multiplying when converting GB to TB.
Put it right: The number of terabytes is smaller, so divide by 1,000.
Confusing the symbol T with the prefix for another unit or writing TB when GB is meant.
Put it right: Check which unit is larger before converting.
Exam tips
- Write the prefix powers (10³, 10⁶, 10⁹, 10¹²) beside the question before converting so the factor of 1,000 is visible.
- Sanity-check the direction: a storage figure in TB should be a smaller number than the same storage in GB.
- Show the division or multiplication by 1,000 in your working so a slip in arithmetic is easy to spot and correct.
Try the lesson
The start of the Units of information: tera, 1 TB is 1,000 Gigabytes. lesson, made from checked teaching notes for this specification point.
Have a go first
Using the decimal (SI) convention, how many gigabytes are there in 1 terabyte?
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