Storage Calculator
Calculate total storage needed for a quantity of items at a given size each - e.g. how much space 5,000 photos at 4MB each require.
Enter how many items you have and the size of each - this tool calculates the total storage required, with a decimal/binary unit choice.
Manufacturers state capacity using decimal (1 GB = 1,000,000,000 bytes) multiples; operating systems commonly display it using binary (1 GiB = 1,073,741,824 bytes) multiples - which is why a "2 TB" drive shows as roughly 1.82 TB in your OS. Both figures are shown so you can see the difference.
More Data / Number / Computer Science Tools
View all 19For converting a single value between size units instead of calculating a total, see the Byte Converter or KB/MB/GB/TB Converter.
What Does This Tool Calculate?
Given a quantity of identical (or average-sized) items and the size of each one, this multiplies them together to estimate the total storage space required - useful for planning how much disk space, cloud storage, or backup capacity you'll need.
How to Use It
- Enter the number of items (photos, videos, files, etc.).
- Enter the average size of one item, with its unit.
- Choose decimal or binary convention for the result.
- View the total storage required.
Limitations
This assumes all items are the same size (or you're using a reasonable average) - real file sizes vary, so treat the result as a planning estimate rather than an exact prediction.
Worked Examples
- Photos: 5,000 photos × 4 MB = 20,000 MB = 20 GB.
- Video: 120 hours of CCTV at 1 GB per hour = 120 GB per camera; four cameras need 480 GB.
- Documents: 200,000 PDFs averaging 300 KB = 60,000,000 KB = 60 GB.
Plan for More Than the Raw Total
- Growth: multiply by how long you keep data. 20 GB of new photos per year for three years is 60 GB.
- Backups: the 3-2-1 rule (three copies, two media types, one off-site) triples the space you need.
- Headroom: keep 15-20% free - full disks slow down and some filesystems behave badly.
- Units: a "1 TB" drive shows about 931 GB in Windows, so compare like with like.
Estimating the Average Size
Select a sample folder, check its total size and divide by the number of files. That gives a far better average than guessing from a single file.
Convert the result between units with the Byte Converter, estimate upload time with the Download Time Calculator, and estimate a single file's size with the File Size Calculator.
Frequently Asked Questions
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