Bits & Bytes: Reading Data Sizes and Speeds
Data sizes and speeds are quoted in bits and bytes that look almost identical but differ by a factor of eight — which is why a fast connection can feel slower than its headline number. Untangling bits from bytes clears up most of the confusion.
Bit vs byte
A bit is a single 1 or 0 — the smallest unit of data. A byte is eight bits, and is enough to store one character of text. The crucial convention: a lowercase b means bits (Mbps, megabits per second), an uppercase B means bytes (MB, megabytes). That one letter is worth a factor of eight.
Why downloads look slow
Internet speeds are sold in megabits per second (Mbps), but files are measured in megabytes (MB). To turn a speed into a download rate, divide by eight: a 100 Mbps connection downloads at about 12.5 MB/s at best. The numbers are both correct — they just use different units.
KB, MB, GB
Each step up is about a thousand of the one below: a kilobyte (KB) is about a thousand bytes, a megabyte (MB) about a thousand KB, a gigabyte (GB) about a thousand MB. A photo might be a few MB, a movie a few GB. The Data Storage Converter moves between all of them.
1000 vs 1024
There is a long-running ambiguity: historically a "kilobyte" often meant 1,024 bytes rather than 1,000. Storage makers use 1,000, so a "1 TB" drive shows as about 931 GB in an operating system that counts in 1,024s. Both are right by their own definition — the mismatch is why a new drive looks smaller than advertised.
Frequently asked questions
Is Mbps the same as MBps? No — Mbps is megabits, MBps is megabytes, eight times larger. Providers quote the smaller.
Why is my drive smaller than the label? Because the maker counts in 1,000s and your OS often counts in 1,024s.
How big is a byte? Eight bits — enough for one text character.
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Last updated: August 27, 2026