Data Storage Converter
Convert between digital storage units: bytes, KB, MB, GB, TB, and more.
Quick Examples
Data Storage Units
Binary vs Decimal
Decimal (KB, MB): 1000 base (SI standard)
Storage manufacturers use decimal (1000). Operating systems often use binary (1024), causing the "missing" space on drives.
Unit Sizes
| Unit | Binary | Decimal |
|---|---|---|
| Kilobyte (KB) | 1024 B | 1000 B |
| Megabyte (MB) | 1024 KB | 1000 KB |
| Gigabyte (GB) | 1024 MB | 1000 MB |
| Terabyte (TB) | 1024 GB | 1000 GB |
| Petabyte (PB) | 1024 TB | 1000 TB |
Common File Sizes
- Text message: ~1 KB
- Photo (smartphone): 3-5 MB
- MP3 song: 3-8 MB
- HD movie: 4-8 GB
- Video game: 50-150 GB
What Is Data Storage?
Everything a computer stores is a string of bits — ones and zeros. Eight bits make a byte, historically the space needed for one text character, and every larger unit counts bytes (or bits) in bulk. The bit-vs-byte distinction is the source of most data-size confusion.
Why Your 1 TB Drive Shows 931 GB
This is the single most-searched data-storage question, and the answer is two measuring systems disagreeing:
- Step 1 — What the manufacturer means: 1 TB (decimal/SI) = 1,000,000,000,000 bytes.
- Step 2 — What the operating system counts: many systems report in binary units, where 1 GiB = 1,073,741,824 bytes, but still print the label "GB".
- Step 3 — Divide: 1,000,000,000,000 ÷ 1,073,741,824 = 931.32. That is the number your file manager shows.
- Step 4 — The rest: file systems, metadata, and recovery partitions reserve a few more percent on top.
No storage is missing — the same bytes are just being counted in larger units. The gap widens at each step: KB vs KiB differ by 2.4%, but TB vs TiB differ by almost 10%.
Bits vs Bytes: Network Speeds
Internet speeds are sold in bits per second (Mbps), while files are measured in bytes. To get a real download rate, divide by 8: a 100 Mbps connection moves at most 12.5 MB/s. A 1 GB file (8,000 megabits) then takes about 80 seconds at line rate — before overhead, congestion, and Wi-Fi losses.
Worked Examples
Example 1: Download size in mebibytes
A game download is listed as 2.5 GB (decimal): 2.5 × 1,000,000,000 = 2,500,000,000 bytes; ÷ 1,048,576 = 2,384.19 MiB. The number goes up because a MiB is smaller than the GB it replaces — more of them fit.
Example 2: Phone storage in binary
A 500 GB phone: 500,000,000,000 ÷ 1,073,741,824 = 465.66 GiB — what the OS reports before its own overhead.
Example 3: How many photos fit in 1 GB?
At roughly 4 MB per smartphone photo: 1,024 ÷ 4 = 256 photos per GB (using binary GB). At 2–3 MB per photo (modern HEIC format), it is 350–500.
Common Mistakes
- Reading "MB" as "MiB": some systems label GiB as "GB" — match the unit to the system that produced the number.
- Dividing Mbps by 10 instead of 8: the bit-to-byte factor is exactly 8.
- Expecting a fixed number of photos per GB: file sizes vary — use the per-photo average from your own camera roll.
- Confusing storage with memory: RAM sizes are binary by design; drive sizes are decimal by convention — both are legitimate.
Transfer Times: How Long to Move 1 GB?
At the rated speed with no overhead, moving 1 GB (8,000 megabits) takes:
| Connection | Rated Speed | 1 GB Transfer Time |
|---|---|---|
| USB 2.0 flash drive | 480 Mbps | ~17 s |
| Typical home broadband | 100 Mbps | 80 s |
| Fast fiber | 1 Gbps | 8 s |
| 4G mobile | 25 Mbps | ~5.3 min |
Real times run 10–30% longer because of protocol overhead, congestion, and storage write speeds. Estimate with time = (file size in bits) ÷ (speed in bits per second), then add margin.
How Much Storage Do You Actually Need?
| Use | Rough Guideline |
|---|---|
| Documents and email | 64–128 GB is plenty |
| Smartphone (photos, apps) | 128–256 GB |
| Laptop (general use) | 256–512 GB |
| Photo/video hobbyist | 1–2 TB |
| 4K video editing | 4 TB and up, plus backups |
| Gaming PC | 1–2 TB (modern titles run 50–150 GB each) |
Whatever you buy, keep 10–15% free: operating systems and SSDs slow down and wear faster when nearly full, and the binary-vs-decimal gap means a "1 TB" drive really offers about 931 GiB before formatting.
The Full Prefix Ladder: Beyond Tera
| Decimal (SI) | Value | Binary (IEC) | Value |
|---|---|---|---|
| kilo (K) | 10³ | kibi (Ki) | 2¹⁰ |
| mega (M) | 10⁶ | mebi (Mi) | 2²⁰ |
| giga (G) | 10⁹ | gibi (Gi) | 2³⁰ |
| tera (T) | 10¹² | tebi (Ti) | 2⁴⁰ |
| peta (P) | 10¹⁵ | pebi (Pi) | 2⁵⁰ |
| exa (E) | 10¹⁸ | exbi (Ei) | 2⁶⁰ |
| zetta (Z) | 10²¹ | zebi (Zi) | 2⁷⁰ |
| yotta (Y) | 10²⁴ | yobi (Yi) | 2⁸⁰ |
The SI added ronna (10²⁷) and quetta (10³⁰) in 2022 for data-scale science — the world now generates on the order of a hundred zettabytes a year. The 2.4%/4.9%/7.4%/9.9% drift between the columns is exactly the "missing space" effect, compounding at each step.
Frequently Asked Questions
How many MB are in a GB? 1,000 MB in the decimal (SI) standard; 1,024 MiB in one GiB under the binary (IEC) standard.
What is the difference between MB and MiB? A megabyte (MB) is 1,000,000 bytes; a mebibyte (MiB) is 1,048,576 bytes. The IEC introduced the "-bi" names in 1998 to end the ambiguity.
How many GB are in a TB? Exactly 1,000 GB (decimal). In binary units, 1 TiB = 1,024 GiB.
Is a bit bigger than a byte? No — a byte is 8 bits. The bit is the smallest unit of digital information.
Why do ISPs advertise in Mbps instead of MB/s? Bits make the number eight times larger. It is the same speed measured differently — always divide by 8 for the download rate.