About FileSizeCalc

FileSizeCalc is a set of free calculators for the numbers that surround files: how big they are, how long they take to move, and how many of them fit on a drive. Every calculator runs locally in your browser — there is no account, no upload, and no server-side processing of what you type.

Why these specific problems

Storage arithmetic is where the confusing parts of computing meet: SI prefixes with two competing definitions, network speeds in bits against file sizes in bytes, bitrates that vary with content, and file systems that keep a slice of every drive. Most tools quietly pick one convention and let the user discover the other the hard way. These pages show both, state the formula, and explain the assumptions — so the number you leave with is one you can defend.

What the calculators do not claim

• They do not measure your connection, your drive or your camera — they do arithmetic on the values you enter.
• Transfer estimates assume a healthy link; real throughput is 90–95% of line rate on Ethernet and often 50–80% over Wi-Fi.
• Bitrate presets are honest averages: two files at the same setting can differ by several times depending on content.
• Capacity counts subtract file-system overhead in a separate conservative row rather than pretending it does not exist.

Privacy, in one paragraph

Nothing you type into a calculator leaves your device. We do not run accounts and have no server that receives your inputs. The site uses privacy-respecting analytics to count page views and serves ads to pay for hosting — see the privacy policy for the details.

Corrections welcome

If a number here disagrees with a specification you can point at — a vendor document, a standard, a measured result — tell us. The contact page explains what to include.