Data Storage Unit Converter — Bytes, KB, MB, GB, TB Explained
Convert data storage units — bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes. Covers both decimal (SI) and binary (IEC) definitions.
Data storage units are deceptively complicated. On the surface it looks simple: 1 KB is 1,000 bytes, right? Except sometimes it's 1,024 bytes. The reason your 1 TB hard drive shows up as "931 GB" in Windows isn't a mistake — it's two different definitions of the same word being used by different parties. This confusion has been around since the 1970s and it's still causing headaches today.
The CalcHub data storage converter handles both definitions and shows you which one you're using.
Data Storage Conversion Table (Decimal / SI)
This is what hard drive manufacturers, ISPs, and storage specs typically use:
| Unit | Bytes |
|---|---|
| 1 Kilobyte (KB) | 1,000 bytes |
| 1 Megabyte (MB) | 1,000,000 bytes |
| 1 Gigabyte (GB) | 1,000,000,000 bytes |
| 1 Terabyte (TB) | 1,000,000,000,000 bytes |
| 1 Petabyte (PB) | 1,000,000,000,000,000 bytes |
Data Storage Conversion Table (Binary / IEC)
This is what operating systems (Windows, macOS, Linux) typically use internally:
| Unit | Bytes |
|---|---|
| 1 Kibibyte (KiB) | 1,024 bytes |
| 1 Mebibyte (MiB) | 1,048,576 bytes |
| 1 Gibibyte (GiB) | 1,073,741,824 bytes |
| 1 Tebibyte (TiB) | 1,099,511,627,776 bytes |
The "Missing Space" Problem Explained
When you buy a 1 TB hard drive, the manufacturer measures it as 1,000,000,000,000 bytes. Your operating system measures storage in binary GiB (1,073,741,824 bytes per unit) — so it divides the same number of bytes differently and reports 931 GiB, which it calls "GB" on screen (because most OS interfaces still use the wrong label).
The actual bytes on the drive are identical — it's purely a labeling mismatch. Nobody stole 69 GB from you.
| Drive Label | Manufacturer's bytes | What OS shows |
|---|---|---|
| 500 GB | 500,000,000,000 bytes | ~465 GB |
| 1 TB | 1,000,000,000,000 bytes | ~931 GB |
| 2 TB | 2,000,000,000,000 bytes | ~1.82 TB |
| 4 TB | 4,000,000,000,000 bytes | ~3.64 TB |
How to Use the CalcHub Data Storage Converter
- Open calchub.in and navigate to the Data Storage Converter
- Enter your value
- Select the unit you're starting with (e.g., "GB")
- See the equivalent in all other units at once
Practical File Size Reference
| What It Is | Typical Size |
|---|---|
| 1 minute of voice call (compressed) | ~500 KB |
| A high-res JPEG photo | 3–8 MB |
| A 3-minute MP3 song | 3–5 MB |
| A 1-hour SD video | ~700 MB |
| A 1-hour HD (1080p) video | 3–8 GB |
| A 4K movie (2 hours) | 50–100 GB |
| Full OS installation (Windows) | 20–40 GB |
Common Mistakes
Confusing MB and Mb. Uppercase B = bytes; lowercase b = bits. Internet speeds are measured in megabits per second (Mbps). Storage is measured in megabytes (MB). 1 byte = 8 bits, so a 100 Mbps internet connection downloads at about 12.5 MB/s. Assuming all GB are the same. When a phone says "128 GB storage," that's decimal GB. When an app says it needs "2 GB RAM," that might be binary GiB, depending on the operating system. Close enough for casual use but important when precise.Why do ISPs advertise speeds in Mbps instead of MB/s?
Because Mbps (megabits per second) sounds bigger than MB/s (megabytes per second) — a 100 Mbps connection is only 12.5 MB/s. Legally it's accurate since the unit is labeled correctly, but it's absolutely a marketing choice.
What is a petabyte used for?
Petabytes are used by large organizations and data centers. Google processes roughly 100 petabytes of data per day. The entire Library of Congress is estimated at about 10–20 terabytes — a petabyte is 1,000 of those.
How many photos fit on 1 GB?
At typical smartphone quality (8–12 MB per photo), about 80–125 photos per GB. Lower-resolution photos (3–4 MB each) get you 250–330 photos. Videos shrink that number dramatically.
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