Byte Size Converter
Convert between all data size units at once, decimal or binary
| Unit | Value |
|---|
The Byte Converter turns one data size into every other unit at once — bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes — in either the decimal (1000) or binary (1024) convention, with an optional bits column for network math. Enter a number, choose its unit, and the full conversion table appears instantly. It is the tool for the two questions that come up constantly: why a drive holds less than its label claims, and how long a download will take on a given connection.
How to Use
- Enter a value, such as
500. - Pick the source unit: B, KB, MB, GB, TB, or PB.
- Choose the base. Decimal (1000) uses SI units; Binary (1024) uses IEC units and labels them KiB, MiB, GiB so the distinction stays visible.
- Read the table for every equivalent unit at once, or tick the bits column to add b/Kb/Mb values for bandwidth work.
Why a 1 TB Drive Shows as 931 GiB
This single discrepancy explains a large share of calls to any storage vendor’s support desk. Manufacturers advertise capacity in decimal units because the numbers are larger and the math is cleaner: 1 TB = 1000 GB = 1,000,000,000,000 bytes. Operating systems report the same physical bytes in binary units, where each step is a factor of 1024 rather than 1000.
Divide a trillion bytes by 1024 once for KiB, again for MiB, again for GiB, and again for TiB, and you land at approximately 931 GiB. The drive contains exactly the number of bytes it was sold with. The label and the operating system are simply speaking two different dialects of the same measurement, and the gap grows as units get larger — about 7% at the gigabyte level, roughly 10% by the terabyte level.
Worked Examples
Example 1 — estimating a download. A 4.7 GB ISO on a 50 Mbps connection. Convert the file to bits: 4.7 GB × 1000 MB × 8 = 37,600 Mb. At 50 Mbps that is about 752 seconds, or roughly 12.5 minutes at full line speed. Real throughput is usually 80–90% of the advertised rate, so plan for 14–15 minutes. The factor of eight between bytes and bits is the step people skip, and it turns a two-minute answer into a wildly wrong one.
Example 2 — comparing cloud storage plans. One provider offers 100 GB and another advertises 95 GiB. Converted to the same base, 95 GiB is about 102 GB — the second plan is slightly larger despite the smaller-looking number. Quoting units consistently is the only way to compare plans honestly, and the binary base is what most billing systems actually use.
Example 3 — sizing an image asset. A design export reads 2,400 KB. Switching to the binary base shows that as about 2.34 MiB, which is below the 2.5 MiB upload limit on a platform that reports limits in binary units. The same file expressed in decimal MB would have looked like 2.4 MB and caused a confusing rejection.
Bits vs Bytes: The Factor of Eight
One byte is eight bits, and that relationship produces most bandwidth estimation errors. Connection speeds, streaming bitrates, and network interfaces are measured in bits per second; file sizes, memory, and storage are measured in bytes. Every comparison between the two requires multiplying or dividing by eight.
A practical shortcut: divide the connection speed by eight to get megabytes per second. 100 Mbps becomes about 12.5 MB/s, 1 Gbps becomes 125 MB/s. From there, a 1 GB file takes roughly 80 seconds on the gigabit line and 80 seconds per 100 MB on the slower one. Keeping the factor of eight in mind is enough to give a credible estimate in your head.
Decimal vs Binary Units, Precisely
| Value | Decimal (SI) | Binary (IEC) |
|---|---|---|
| 1000 / 1024 bytes | 1 KB | 1 KiB |
| 1000² / 1024² bytes | 1 MB | 1 MiB |
| 1000³ / 1024³ bytes | 1 GB | 1 GiB |
| 1000⁴ / 1024⁴ bytes | 1 TB | 1 TiB |
The IEC names were standardized in 1998 to end the ambiguity, but adoption has been uneven: storage vendors stayed with decimal, operating systems mostly stayed with binary, and networking uses decimal for throughput. The result is that “GB” on a disk label and “GB” in a system dialog can mean two different quantities. This converter labels both bases explicitly so there is no guessing which one produced a number.
Common Mistakes
- Mixing bases within one calculation. Multiplying a binary capacity by a decimal rate produces a number that is wrong by a few percent — small in absolute terms and large enough to break a quota check.
- Forgetting the byte-to-bit conversion. Download time estimates are off by a factor of eight, not a few percent, when this step is skipped.
- Reading 931 GiB as a faulty drive. It is a unit conversion, not missing space. The filesystem overhead is a separate, much smaller factor.
- Assuming every tool uses the same convention. Two calculators can disagree on “GB” by 7%. Note which base you are feeding in.
- Applying the conversion to storage only. Memory is almost always binary, network throughput almost always decimal, and disks depend on the vendor — the context determines the right unit.
Features
- One input converts to B, KB, MB, GB, TB, and PB simultaneously
- Switchable decimal (1000) and binary (1024) bases with correct KiB/MiB/GiB labels
- Optional bits column for bandwidth and transfer-rate calculations
- Large-value support up to petabytes
- Instant, offline-capable client-side arithmetic
- No data leaves the browser
Use Cases
- Storage shopping: Compare capacity across vendors that use different units.
- Bandwidth planning: Convert file sizes to bits to estimate upload or download time.
- Cloud quotas: Reconcile billing units with what the operating system reports.
- Media work: Convert footage or export sizes before checking against a platform limit.
- Infrastructure: Size volumes, backups, and log retention in consistent units.
Related Tools
Frequently Asked Questions
Why does my 1 TB drive show as 931 GiB?
The drive really does hold 1,000,000,000,000 bytes, because manufacturers label capacity in decimal units where 1 TB = 1000 GB and 1 GB = 1000 MB. Your operating system reports the same bytes in binary units, where 1 TiB = 1024 GiB, and a trillion bytes divided by 1024 four times over comes to about 931 GiB. Nothing is missing — the two sides are counting in different bases.
Is a megabyte 1000 or 1024 kilobytes?
Both definitions exist and are used, which is the source of the confusion. In the SI decimal system, 1 MB = 1000 KB; in the IEC binary system, 1 MiB = 1024 KiB. The IEC introduced the -bi- prefixes (KiB, MiB, GiB) precisely so the two could be told apart. This converter shows both bases so you can match whichever convention your context uses.
How do I convert a file size to download time?
Convert the file to bits, then divide by the connection speed in bits per second. A 700 MB file is 700 × 8 = 5,600 Mb, so on a 100 Mbps line it takes about 56 seconds at full speed. Remember that advertised connection speeds are in megabits per second, while file sizes are in bytes — the factor of eight is where most estimates go wrong.
Why do network speeds use megabits instead of megabytes?
Because historically, serial links transmit one bit at a time, and measuring throughput in bits per second describes the link directly. Storage, meanwhile, is addressed in bytes, so file sizes are quoted in bytes. The mismatch is old and permanent, which is why the conversion factor of eight matters whenever you compare a download size against a connection speed.
Does the converter handle very large or very small values?
Yes, it covers the full decimal range from bytes up to petabytes in a single table, and switching to the binary base relabels the columns as KiB through PiB. For values below one unit, use a smaller source unit — for example, enter kilobytes and read the byte row rather than typing a fraction.
Is my data uploaded when I convert?
No. The arithmetic runs entirely in your browser with JavaScript. Nothing you type is transmitted, and there is no account or history — the numbers exist only in the tab until you close it.
Reviewed by the HandyTools Hub team · Last updated