Data Storage Converter
Enter a size and a unit and see it in every bit and byte unit at once, decimal (kB, MB, GB — powers of 1000) beside binary (KiB, MiB, GiB — powers of 1024), with exact digits. The second half estimates how long that amount takes to transfer at a bandwidth you choose, keeping megabits and megabytes straight. Free, no sign-up, and everything runs in your browser.
A size such as 500, 1.5 or 256. Convert between bits, bytes, decimal units (kB, MB, GB) and binary units (KiB, MiB, GiB).
Result
1,000,000,000,000
Bytes
8,000,000,000,000
Bits
0.909495 TiB
The same TB in binary units
Every unit
| Unit | Name | Value |
|---|---|---|
| bit | bit | 8,000,000,000,000 |
| B | byte | 1,000,000,000,000 |
| Unit | Name | Value |
|---|---|---|
| kB | kilobyte | 1,000,000,000 |
| MB | megabyte | 1,000,000 |
| GB | gigabyte | 1,000 |
| TB | terabyte | 1 |
| PB | petabyte | 0.001 |
| EB | exabyte | 0.000001 |
| ZB | zettabyte | 1 × 10⁻⁹ |
| YB | yottabyte | 1 × 10⁻¹² |
| Unit | Name | Value |
|---|---|---|
| KiB | kibibyte | 976,562,500 |
| MiB | mebibyte | 953,674.3164 |
| GiB | gibibyte | 931.3225746 |
| TiB | tebibyte | 0.9094947018 |
| PiB | pebibyte | 0.0008881784197 |
| EiB | exbibyte | 8.67361738 × 10⁻⁷ |
| ZiB | zebibyte | 8.470329473 × 10⁻¹⁰ |
| YiB | yobibyte | 8.271806126 × 10⁻¹³ |
| Unit | Name | Value |
|---|---|---|
| kbit | kilobit | 8,000,000,000 |
| Mbit | megabit | 8,000,000 |
| Gbit | gigabit | 8,000 |
| Tbit | terabit | 8 |
| Pbit | petabit | 0.008 |
| Kibit | kibibit | 7,812,500,000 |
| Mibit | mebibit | 7,629,394.531 |
| Gibit | gibibit | 7,450.580597 |
| Tibit | tebibit | 7.275957614 |
| Pibit | pebibit | 0.007105427358 |
Why 1000 and 1024 are not the same
Each decimal prefix is slightly smaller than its binary twin, and the gap compounds at every step. This is why a drive sold as 1 TB shows up as about 931 GiB in software that counts in powers of 1024.
| Decimal / binary | Decimal size in bytes | Binary size in bytes | Decimal is smaller by |
|---|---|---|---|
| kB / KiB | 1,000 | 1,024 | 2.3% |
| MB / MiB | 1,000,000 | 1,048,576 | 4.6% |
| GB / GiB | 1,000,000,000 | 1,073,741,824 | 6.9% |
| TB / TiB | 1,000,000,000,000 | 1,099,511,627,776 | 9.1% |
| PB / PiB | 1,000,000,000,000,000 | 1,125,899,906,842,624 | 11.2% |
| EB / EiB | 1,000,000,000,000,000,000 | 1,152,921,504,606,846,976 | 13.3% |
| ZB / ZiB | 1,000,000,000,000,000,000,000 | 1,180,591,620,717,411,303,424 | 15.3% |
| YB / YiB | 1,000,000,000,000,000,000,000,000 | 1,208,925,819,614,629,174,706,176 | 17.3% |
Transfer time
How long the amount above takes to move at a given speed. Network speeds are quoted in bits per second; file sizes are in bytes.
For example 100 for a 100 Mbit/s connection.
Real transfers rarely reach the advertised speed — protocol overhead and congestion take a share. 100 means the full line rate.
2 h 13 min 20 s
Transfer time
8,000
Seconds
| Unit | Name | Speed |
|---|---|---|
| Mbit/s | megabit | 1,000 |
| MB/s | megabyte | 125 |
| MiB/s | mebibyte | 119.209 |
How to Use the Data Storage Converter
- 1. Enter an amount and pick its unit. Any size works, including decimals such as
1.5. The list covers bits, bytes, and both the decimal and binary prefixes up to yotta and yobi. - 2. Read the tables. Every other unit is shown with exact digits, grouped into bits and bytes, decimal bytes, binary bytes and bits. Values too small to write plainly appear as a power of ten.
- 3. Compare the systems. The summary card gives the same prefix in the other system, so 1 TB shows next to its TiB value, and the gap table shows how the difference grows.
- 4. Estimate a transfer. Enter a speed, its unit and, if you like, a link efficiency below 100%. The result is a time, the seconds behind it, and the speed restated in Mbit/s, MB/s and MiB/s.
Decimal and Binary Prefixes
The SI prefixes kilo, mega, giga and the rest always mean powers of 1000. Computers address memory in powers of two, so for decades "kilobyte" was also used for 1,024 bytes. To end the ambiguity the IEC introduced separate binary prefixes at the end of the 1990s, and IEC 80000-13 now defines both sets. A kibibyte (KiB) is exactly 1,024 bytes; a kilobyte (kB, with a lowercase k) is exactly 1,000.
| Prefix | Decimal (SI) | Bytes | Binary (IEC) | Bytes |
|---|---|---|---|---|
| Kilo / kibi | kB | 1,000 | KiB | 1,024 |
| Mega / mebi | MB | 1,000,000 | MiB | 1,048,576 |
| Giga / gibi | GB | 1,000,000,000 | GiB | 1,073,741,824 |
| Tera / tebi | TB | 1,000,000,000,000 | TiB | 1,099,511,627,776 |
Why a 1 TB Drive Shows About 931 GB
Storage makers count in decimal, so a 1 TB drive holds exactly 1,000,000,000,000 bytes. Divide that by 1,073,741,824 and you get 931.32 GiB. Some software then prints the figure with the label "GB": Windows, for one, divides by 1,024 per step but keeps the decimal symbol. macOS has counted in decimal since 2009, so the same drive reads 1 TB there, and Linux tools vary — df -H is decimal, df -h is binary. Nothing is missing from the drive; two systems are using one word for two sizes.
The gap compounds with each prefix. A kilobyte is 2.3% smaller than a kibibyte, a megabyte 4.6% smaller than a mebibyte, a gigabyte 6.9% smaller, and a terabyte 9.1% smaller than a tebibyte. Memory is the opposite case: it is built in powers of two, so 16 GB of RAM is really 16 GiB.
Bits, Bytes and Network Speeds
A byte is 8 bits. File sizes are quoted in bytes, but network speeds are quoted in bits per second and always in decimal prefixes: 1 Mbit/s is 1,000,000 bits per second. Capital and lowercase matter — Mbit/s or Mb/s is megabits, MB/s is megabytes, and they differ by a factor of eight. A 100 Mbit/s connection therefore moves at most 12.5 MB/s, which is 11.92 MiB/s, and a 1 GB file takes at least 80 seconds to arrive.
Worked Example: Moving 1 TB over Gigabit Ethernet
- Size in bits: 1 TB is 1012 bytes × 8 = 8 × 1012 bits.
- Speed in bits per second: 1 Gbit/s is 109 bits per second.
- Time at full speed: 8 × 1012 ÷ 109 = 8,000 seconds, or 2 hours 13 minutes 20 seconds.
- Add reality: a full-size TCP segment on Ethernet carries 1,460 bytes of data in 1,538 bytes on the wire, about 95%. At 95% efficiency the same transfer takes about 8,421 seconds, or 2 hours 20 minutes 21 seconds.
Which Unit Should You Write?
Use the unit that matches what you measured. For a drive's advertised capacity, a download size or a network rate, the decimal units (kB, MB, GB) are standard. For memory, or for a size reported by an operating system that counts in 1,024s, write KiB, MiB or GiB so a reader cannot mistake it for the decimal figure. In a paper or specification, state the convention once — for example "1 GB = 109 bytes" — and keep to it. The converter shows both columns so you can quote either with confidence.
Frequently Asked Questions
- What is the difference between KB and KiB?
- KiB, the kibibyte, is exactly 1,024 bytes and is the IEC binary unit. kB, the kilobyte, is exactly 1,000 bytes in the SI system. A capital "KB" is informal and has been used for both, which is why the standardised symbols exist. The same applies to MB and MiB, GB and GiB, and so on.
- Why does my 1 TB hard drive show only 931 GB?
- The drive really holds 1,000,000,000,000 bytes. Software that divides by 1,024 three times shows 931 of its gigabytes, which are gibibytes in the standard's terms. No space is lost; the maker counted in decimal and the operating system in binary.
- How many bytes are in a gigabyte?
- In the SI definition, 1,000,000,000 bytes. A gibibyte, the binary unit often called a gigabyte in older software, is 1,073,741,824 bytes. Use GiB when you mean the latter.
- What is the difference between Mbps and MBps?
- Mbps (megabits per second) measures network speed; MBps (megabytes per second) measures file transfer speed. One byte is eight bits, so 8 Mbps equals 1 MBps. Internet plans are quoted in megabits, which is why a 200 Mbps plan downloads at no more than 25 MB/s.
- How do I calculate download time?
- Convert the file size to bits (bytes × 8) and divide by the speed in bits per second. For example, 500 MB is 4,000,000,000 bits, and at 50 Mbit/s it takes 80 seconds. Real downloads run slower than the advertised speed, so treat the answer as a lower bound or lower the efficiency.
- Is RAM measured in GB or GiB?
- RAM is built in powers of two, so a module sold as 16 GB holds 16 GiB, which is 17,179,869,184 bytes. Storage devices are the opposite: they follow the decimal definition. That mismatch is the source of most confusion about capacity.