Data Storage Converter
Convert bits, bytes, KB, MB, GB and TB — and the binary KiB, MiB, GiB, TiB — and see why a 1 TB drive shows up as 931 GB. Decimal vs binary explained.
Data Storage Converter: with the default inputs, gigabytes (gb, 10⁹) is 1,000 GB.
- Bytes
- 1,000,000,000,000 B
- Bits
- 8,000,000,000,000 bit
- Kilobytes (KB, 10³)
- 1,000,000,000 KB
- Megabytes (MB, 10⁶)
- 1,000,000 MB
- Terabytes (TB, 10¹²)
- 1 TB
- Kibibytes (KiB, 2¹⁰)
- 976,562,500 KiB
- Mebibytes (MiB, 2²⁰)
- 953,674.316406 MiB
- Gibibytes (GiB, 2³⁰)
- 931.322575 GiB
- Tebibytes (TiB, 2⁴⁰)
- 0.909495 TiB
- Time to transfer at 100 Mbit/s
- 22.2 hoursBytes × 8 ÷ 100,000,000 — a typical home broadband speed.
Assumptions
- KB/MB/GB/TB are decimal (powers of 1,000); KiB/MiB/GiB/TiB are binary (powers of 1,024).
- A byte is 8 bits.
| Decimal | Bytes | Binary | Bytes | Difference |
|---|---|---|---|---|
| 1 KB (kilobyte) | 1,000 | 1 KiB (kibibyte) | 1,024 | 2.4% |
| 1 MB (megabyte) | 1,000,000 | 1 MiB (mebibyte) | 1,048,576 | 4.9% |
| 1 GB (gigabyte) | 10⁹ | 1 GiB (gibibyte) | 1,073,741,824 | 7.4% |
| 1 TB (terabyte) | 10¹² | 1 TiB (tebibyte) | 1,099,511,627,776 | 10.0% |
| 1 PB (petabyte) | 10¹⁵ | 1 PiB (pebibyte) | 2⁵⁰ | 12.6% |
| Advertised | Bytes | Shown as |
|---|---|---|
| 128 GB | 128,000,000,000 | 119.2 GB |
| 256 GB | 256,000,000,000 | 238.4 GB |
| 512 GB | 512,000,000,000 | 476.8 GB |
| 1 TB | 1,000,000,000,000 | 931.3 GB |
| 2 TB | 2,000,000,000,000 | 1,862.6 GB |
| 4 TB | 4,000,000,000,000 | 3,725.3 GB |
| Approx. size | |
|---|---|
| Plain-text email | 5 KB |
| Smartphone photo (JPEG) | 3–5 MB |
| MP3 song (4 min, 256 kbps) | 8 MB |
| RAW photo | 25–50 MB |
| 1 hour of HD streaming video | 3 GB |
| 1 hour of 4K streaming video | 7 GB |
| Blu-ray movie | 25–50 GB |
| Modern AAA video game | 100–150 GB |
How this is worked out
The formula
1 byte = 8 bits Decimal (SI): 1 KB = 1,000 B; 1 MB = 10⁶ B; 1 GB = 10⁹ B; 1 TB = 10¹² B Binary (IEC): 1 KiB = 1,024 B; 1 MiB = 2²⁰ B; 1 GiB = 2³⁰ B; 1 TiB = 2⁴⁰ B value in unit B = bytes ÷ (bytes per unit B)
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Amount of data
- A number.in TB · 0 or more · defaults to 1
What you get back
- Gigabytes (GB, 10⁹)main answer
- Bytes
- Bits
- Kilobytes (KB, 10³)
- Megabytes (MB, 10⁶)
- Terabytes (TB, 10¹²)
- Kibibytes (KiB, 2¹⁰)
- Mebibytes (MiB, 2²⁰)
- Gibibytes (GiB, 2³⁰)
- Tebibytes (TiB, 2⁴⁰)
- Time to transfer at 100 Mbit/s
- Bytes × 8 ÷ 100,000,000 — a typical home broadband speed.
What this assumes
- KB/MB/GB/TB are decimal (powers of 1,000); KiB/MiB/GiB/TiB are binary (powers of 1,024).
- A byte is 8 bits.
About this calculator
Enter an amount of data in any unit and see it in all the others — including both the decimal units drive makers use (GB = 10⁹ bytes) and the binary units operating systems often use under the same name (GiB = 2³⁰ bytes). That confusion is the reason a "1 TB" drive shows 931 GB in Windows; nothing is missing.
Bits and bytes
A bit is a single 0 or 1. A byte is 8 bits — enough for one character of ASCII text. Network speeds are quoted in bits per second (100 Mbps), storage in bytes (100 MB), so a 100 Mbps connection moves 12.5 MB per second, not 100. The converter's transfer-time line does that arithmetic.
Decimal vs. binary
The SI prefixes kilo, mega, giga and tera mean 10³, 10⁶, 10⁹ and 10¹². Early computing borrowed them for the nearby powers of two (2¹⁰ = 1,024), and the two meanings drifted apart as sizes grew: a "kilobyte" of 1,024 is only 2.4% off, but a "terabyte" of 2⁴⁰ bytes is 10% bigger than 10¹². In 1998 the IEC introduced the unambiguous binary prefixes kibi, mebi, gibi and tebi (KiB, MiB, GiB, TiB).
Who uses which:
- Storage manufacturers, network engineers, macOS (since 10.6), Ubuntu — decimal. A 1 TB drive holds 1,000,000,000,000 bytes.
- Windows, many Linux tools, RAM sizes — binary, but often labelled with the decimal symbol. Windows reports that same drive as 931 "GB", meaning 931 GiB.
- RAM is always binary: a 16 GB module holds 16 × 2³⁰ bytes.
Reading the results
Every unit is shown at once, so you can check a claim in either system. The second table lists the common drive sizes and what Windows will display for each — useful for settling "is my drive faulty?" questions (it isn't; a little space also goes to the file system).
Transfer time
The time to transfer line assumes a 100 Mbit/s link, roughly typical home broadband. Scale it: a 1 Gbit/s connection is 10× faster, a 20 Mbit/s upload 5× slower. Real transfers run 10–20% below the headline rate because of protocol overhead.
Frequently asked questions
▸How many MB are in a GB?
1,000 MB in a decimal gigabyte (the storage-industry meaning), or 1,024 MiB in a binary gibibyte. Windows shows binary values with decimal labels, which is where the '1,024 MB in a GB' answer comes from.
▸Why does my 1 TB drive show only 931 GB?
The drive holds 1,000,000,000,000 bytes, as advertised. Windows divides by 2⁴⁰ (1,099,511,627,776) but labels the result 'GB' and 'TB', giving 931.3. macOS divides by 10¹² and shows 1 TB. Nothing is missing.
▸How many bytes are in a kilobyte?
1,000 bytes by the SI definition. A kibibyte (KiB) is 1,024 bytes. Older software and textbooks used 1,024 for 'kilobyte', so context matters.
▸What's the difference between Mbps and MBps?
Mbps is megabits per second, MBps is megabytes per second — 8× larger. A 100 Mbps connection downloads at most 12.5 MB per second, so a 1 GB file takes about 80 seconds.
▸How many GB is 1 TB?
1,000 GB (decimal) or 1,024 GiB (binary). 2 TB is 2,000 GB; 4 TB is 4,000 GB.
Put this calculator on your own site
A working data storage, free for any site, with no ads and no sign-up. It resizes to fit wherever you paste it and updates itself as this page improves.
Paste this anywhere. It works on any site, carries no ads, never expires, and always shows the current version.
Data Storage Converter by CalculateItNow
The page's own title. The clearest description of what the link leads to.
The credit line sits outside the widget on purpose, so it is a real link on your page rather than one buried in a frame. Please keep it — it is what pays for CalculateItNow staying free and ad-free. The script only resizes the widget to fit its contents; drop it and the widget still works.
Browse every calculator widget·How to add it to WordPress, Squarespace or Wix
Related calculators
The questions people ask next to a data storage.
Find what percent one number is of another, take a percentage of a number, or calculate percentage increase and decrease — with the working shown.
Add or subtract two durations in hours, minutes and seconds and get the result as h:mm:ss, decimal hours, total minutes and total seconds — with the carrying shown.
Convert between inches, feet, yards, miles, millimeters, centimeters, meters, kilometers and nautical miles — all at once, with exact factors and a reference table.