About Data Size Converter
Convert between common data-size-converter units instantly. Free online converter. Free, no sign-up required.
How to use
- Type the data quantity into the Value field. Whole numbers and decimals work — 1.5 GB or 250000 bytes are both valid inputs and the conversion runs the moment you stop typing.
- Pick the source unit from the From dropdown. Bytes are the base; you can also start in KB, MB, GB, TB, PB, or jump to bits, kilobits, megabits, and gigabits when working with network speeds.
- Select the target unit in the To dropdown. The converter uses binary (base-1024) factors for byte units, matching what your operating system reports — so the number you see here will match what File Explorer or Finder shows.
- Use the swap button to flip the From and To selectors instantly. Useful when you need to round-trip a value, such as confirming that 8 Gbit really equals 1 GB (it does — 8 bits = 1 byte).
- Read the result in the highlighted box. Numbers are displayed with up to 4 decimal places — accurate enough for storage planning, file transfer estimates, and bandwidth budgeting.
- When in doubt about decimal vs. binary, remember: drive manufacturers use decimal (1 GB = 1,000,000,000 bytes), but operating systems and this converter use binary (1 GiB = 1,073,741,824 bytes). The 7% gap explains the “missing” space on every new drive.
Examples
ISO download speed estimate
A 4.7 GB DVD ISO equals 4,812.8 MB or 38,503 megabits. On a 100 Mbps home connection (12.5 MBps real throughput), that download takes about 6.4 minutes — bits/bytes math you can do in your head once the conversion is clear.
Phone storage in three units
A 256 GB iPhone holds 262,144 MB or 2,199 billion bits. After iOS overhead, expect about 235 GiB free as reported by the system — the gap is decimal-marketing GB versus binary-OS GiB, not missing capacity.
1 PB data center scale
1 petabyte = 1,024 TB = 1,048,576 GB = 1.126 × 10¹⁵ bytes. That is roughly 250 million MP3 files at 4 MB each, or 500 hours of uncompressed 4K video. PB-scale storage now appears in scientific computing, archive systems, and large media libraries.
Frequently asked questions
How do I convert GB to MB or TB?
In binary units (what operating systems use): 1 GiB = 1,024 MiB and 1 TiB = 1,024 GiB = 1,048,576 MiB. In decimal units (used by storage marketing): 1 GB = 1,000 MB and 1 TB = 1,000 GB. This converter uses the binary convention, so a “500 GB” drive that ships with 500,000,000,000 bytes of capacity reports as roughly 465 GiB after the OS converts to base-1024.
Why does my hard drive show less space than advertised?
It is not missing — it is two different units. Manufacturers use SI decimal prefixes where 1 GB = 10⁹ bytes. Operating systems use IEC binary prefixes where 1 GiB = 2³⁰ bytes = 1,073,741,824 bytes. A 1 TB (10¹²-byte) drive reports as roughly 931 GiB. Both labels are technically correct; they reference different definitions of “giga.”
What is the difference between Mbps and MBps?
Mbps (lowercase b) means megabits per second — used for network speeds. MBps (uppercase B) means megabytes per second — used for file transfer rates. Since 1 byte = 8 bits, divide Mbps by 8 to get MBps. A 1 Gbps fiber connection delivers about 125 MBps real-world throughput. ISPs advertise in Mbps because the bigger number sounds faster.
What are KiB, MiB, and GiB — are they the same as KB, MB, GB?
No. The IEC introduced binary prefixes in 1998 to remove ambiguity: KiB = 1,024 bytes (kibibyte), MiB = 1,048,576 bytes (mebibyte), GiB = 1,073,741,824 bytes (gibibyte). The original SI prefixes (KB, MB, GB) were redefined to mean strict powers of 1,000. In practice, Linux and macOS use the IEC prefixes correctly; Windows still labels binary values with “KB/MB/GB,” which is technically incorrect but pragmatic.
How many bytes are in a TB?
Decimal: 1 TB = 1,000,000,000,000 bytes (10¹²). Binary: 1 TiB = 1,099,511,627,776 bytes (2⁴⁰). The 9.95% gap between them grows at every prefix step — it is 2.4% at KB, 4.9% at MB, 7.4% at GB, and 9.95% at TB. By the time you hit petabytes the difference is over 12%, which is why scientific and archival systems usually quote IEC binary explicitly.
What size are common files in bytes?
Rough rules of thumb: a plain text email is about 5 KB; a smartphone photo is 2-5 MB; an MP3 song is 3-5 MB; a 1080p movie file is 1-2 GB; a 4K HDR film is 25-100 GB; a Blu-ray ISO is around 50 GB; a full uncompressed Wikipedia dump is roughly 100 GB. Typing any of these into the converter shows the bit-equivalent for transfer speed estimates.
Are bits and bytes interchangeable?
No — they are exactly 8:1. One byte (B) = 8 bits (b). The convention dates to early computing when an 8-bit byte became the standard machine word. Network engineers count in bits because data is serialized over a wire one bit at a time; storage and memory engineers count in bytes because addressable chunks are bytes. This converter handles both, so you never need to mentally divide or multiply by 8.
Part of ToolFluency’s library of free online tools for Converters. No account needed, no data leaves your device.