Jump to the free byte converter
Short answer: 1 KB is 1,000 bytes, while 1 KiB is 1,024 bytes. The same gap runs up the scale (MB and MiB, GB and GiB, TB and TiB), and it grows from 2.4% at the kilobyte to about 10% at the terabyte. For a single pair such as KB to GB or GB to MB, use the digital storage converters; this guide explains which unit to pick and why the numbers differ.
Understanding Digital Storage Units
Digital storage is measured in bytes: a byte is 8 bits, and each bit is a single 0 or 1 in binary. From there, units scale up by factors of 1,000 (decimal) or 1,024 (binary).
Decimal vs Binary Units
There are two competing standards for measuring digital storage, and the difference matters:
| Decimal (SI) | Binary (IEC) | Difference |
|---|---|---|
| 1 kB = 1,000 bytes | 1 KiB = 1,024 bytes | 2.4% |
| 1 MB = 1,000,000 bytes | 1 MiB = 1,048,576 bytes | 4.9% |
| 1 GB = 1,000,000,000 bytes | 1 GiB = 1,073,741,824 bytes | 7.4% |
| 1 TB = 1,000,000,000,000 bytes | 1 TiB = 1,099,511,627,776 bytes | 10% |
This is why a “1 TB” hard drive shows up as about 931 GB in Windows: the manufacturer counts in decimal, but Windows counts in binary units while still labeling them GB. macOS has counted in decimal since Mac OS X 10.6, so it shows the full 1 TB.
Common Byte Conversions
Decimal Scale
| Unit | Bytes | Abbreviation |
|---|---|---|
| Kilobyte | 1,000 | kB |
| Megabyte | 1,000,000 | MB |
| Gigabyte | 1,000,000,000 | GB |
| Terabyte | 1,000,000,000,000 | TB |
| Petabyte | 1,000,000,000,000,000 | PB |
Quick Conversions
1 GB = 1,000 MB
1 TB = 1,000 GB
1 PB = 1,000 TB
1 byte = 8 bits
1 MB = 8 Mb (megabits)
The lowercase b means bits, uppercase B means bytes. Internet speeds are usually measured in megabits per second (Mbps), while file sizes are in megabytes (MB). To convert: 100 Mbps = 12.5 MB/s.
How Much Storage Do You Need?
| Content Type | Average Size | Files per GB |
|---|---|---|
| Text document | 50 kB | 20,000 |
| High-res photo | 5 MB | 200 |
| MP3 song | 4 MB | 250 |
| 1080p video (per min) | 150 MB | ~7 min |
| 4K video (per min) | 400 MB | ~2.5 min |
Storage Planning Example
Planning storage for a photography project:
| Note | Result |
|---|---|
| photos per shoot = 200 | 200 |
| photo size = 25 MB | 25 MB |
| shoots per month = 4 | 4 |
| monthly storage = photos per shoot × photo size × shoots per month | 20,000 MB |
| monthly storage × 12 | 240,000 MB |
The right pane shows monthly storage as 20,000 MB (or 20 GB after monthly storage in GB) and the annual figure, monthly storage × 12, as 240,000 MB.
If you shoot for a living, our calculator for freelancers and photographers turns this same storage plan into a month of shoots, with a package quote converted for a client abroad.
Free Byte Converter
Convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and more in both decimal and binary units.
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Example
How many megabytes in 2 TB?
| Note | Result |
|---|---|
| size = 2 TB | 2 TB |
| size in GB | 2,000 GB |
| size in MB | 2,000,000 MB |
The right pane shows 2,000 GB and 2,000,000 MB using the decimal (SI) standard.
For one conversion at a time, the digital storage converters have a page per unit pair with a live calculator and a table, such as gigabytes to megabytes, megabytes to gigabytes and gibibytes to gigabytes.
Frequently Asked Questions
How many megabytes are in a gigabyte?
In the decimal (SI) standard used by storage manufacturers, 1 GB = 1,000 MB. In the binary (IEC) standard, used for memory and by Windows, 1 GiB = 1,024 MiB. The decimal standard is more common in everyday use, but the binary standard reflects how computers actually address memory.
Why does my hard drive show less space than advertised?
Hard drive manufacturers use the decimal standard (1 GB = 1,000,000,000 bytes), while Windows reports sizes in binary units (1 GiB = 1,073,741,824 bytes) and still labels them GB. A “1 TB” drive contains 1,000,000,000,000 bytes, which Windows displays as about 931 GB. macOS has counted in decimal since Mac OS X 10.6, so it shows the full 1 TB.
What is the difference between Mbps and MB/s?
Mbps (megabits per second) measures network speed, while MB/s (megabytes per second) measures data transfer rate. Since 1 byte = 8 bits, divide Mbps by 8 to get MB/s. A 100 Mbps internet connection downloads at about 12.5 MB/s in ideal conditions.
Convert Data Units in Notes Calculator
Notes Calculator supports both decimal and binary digital storage units:
| Note | Result |
|---|---|
| photo size = 5 MB | 5 MB |
| photos = 10000 | 10,000 |
| library size = photo size * photos | 50,000 MB |
| library size in GB | 50 GB |
| // Binary units | |
| 1 TB in GiB | 931.32 GiB |
| 1024 KiB in MiB | 1 MiB |
| // Megabits to megabytes: one second at 100 Mbps | |
| 100 Mb in MB | 12.50 MB |
| // How long to download a file? | |
| file size = 4 GB | 4 GB |
| file size in Mb | 32,000 Mbit |
| file size / 100 Mbps | 320 seconds |
The app distinguishes between bits (b, kbit, Mb, Gb) and bytes (B, kB, MB, GB; in the app, kb also means kilobytes), and supports binary units (KiB, MiB, GiB, TiB) alongside decimal ones. Variables let you plan storage needs interactively: change photos and see the total update in real time.
For converting between number bases used in computing, check our hex to decimal converter. For other unit conversions, see the unit converter. And because storage units scale the same way named numbers do, the big numbers guide shows how to write a petabyte’s worth of zeros as a single suffix.
If you size storage for a growing user base, our calculator for developers shows how to multiply per-user storage across users, estimate API cost at your traffic and turn an SLA into minutes of downtime.