File Size Calculator
Adds up a set of files and checks them against a drive.
Total size
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Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
In binary units (powers of 1,024) —
Files that fit —
Share of the capacity — %
The formula
total = average size × number of files files that fit = capacity ÷ average size
A file system uses a little extra space for its own records, so a nearly full drive holds slightly fewer.
What to watch out for
Decimal units (MB, GB) count in thousands and binary units (MiB, GiB) in 1,024s. To convert a single figure, use the data storage converter.
Frequently Asked Questions
How big are 1,000 files of 4 MB?
4.00 GB, which is 3.73 GiB.
How many 4 MB files fit on a 256 GB drive?
64,000, before file system overhead.