Data Storage Converter
Convert between bits, bytes, KB, MB, GB, TB and PB with binary (1024) and decimal (1000) modes.
Reviewed by Aygul Dovletova · Last reviewed
Using the Data Storage Converter
- Type a non-negative value into the input field. The converter accepts decimals and scientific notation.
- Pick the input unit by clicking one of the unit buttons (b, B, KB, MB, GB, TB, PB).
- Choose a base: Binary (powers of 1024, how your OS and RAM report sizes) or Decimal (powers of 1000, how drive and bandwidth makers advertise).
- Read every unit at once. The grid updates live as you type - all seven unit rows recompute from a shared bit-total.
- Click Copy on any row to send that specific value to your clipboard.
What This Tool Is For (vs the Byte Converter)
The focus here is consumer-device comparisons: what a 1 TB SSD really stores, why a 256 GB iPhone shows less than 256 GB free, and how ISP download quotas in GB compare to Netflix-per-hour usage. The byte converter next door is strictly about bits vs bytes and the IEC binary prefixes (KiB / MiB / GiB) versus SI (K / M / G). Here we lean into the marketing mismatch that confuses most people: drive makers advertise decimal, operating systems report binary, and a 1 TB drive looks like "only 931 GB" through that mismatch. Under the hood, every unit is stored as a count of bits. Conversion is integer math where possible, with JavaScript Number fallback above Number.MAX_SAFE_INTEGER (2^53 - 1). The component is Preact, runs fully in your browser, and does not round-trip anything to a server.
When You Will Reach For It
- Buying a hard drive - "is 2 TB (decimal) enough for my 1.5 TB backup (binary)?"
- Budgeting mobile data when the plan says 30 GB and streaming services list MB per minute.
- Sanity-checking cloud bills where an AWS S3 invoice reports storage in GB-months.
- Estimating backup durations: 500 GB over a 100 Mbps pipe takes roughly 40,000 seconds, just over 11 hours.
- Comparing SSD specs - consumer SSDs often show decimal capacity and drop binary-equivalent MB/s write speeds in the same spec sheet.
- Deciding how many 4 MB JPEGs fit in an Instagram cache or an 8 GB photo archive.
Pitfalls and Marketing vs Reality
Hard-drive and SSD manufacturers have used decimal units (1 GB = 1,000,000,000 bytes) since the 1970s because the Federal Trade Commission and international labelling rules treat the SI prefixes literally. Operating systems historically report binary (1 GB = 1,073,741,824 bytes = 2^30), which makes the same physical drive look smaller by about 7-10% depending on the unit. macOS switched to decimal-only reporting in 2009 (Snow Leopard onward) to match drive labels; Windows and Linux still use binary in most tools. Network bandwidth is decimal by convention (100 Mbps = 100,000,000 bits per second), while RAM is always binary (16 GB RAM is really 17,179,869,184 bytes). Cellular data plans are inconsistent: AT&T and Verizon bill in decimal, but your phone\'s data counter often displays binary, so you hit "10 GB used" at 10.74 GB of actual traffic.
The Binary vs Decimal Prefix Story
Until 1998 there was no officially defined way to say "1024 bytes" unambiguously. Computer scientists used "K", "M", "G" with both meanings depending on context, which the industry tolerated because everyone was in the same factor-of-two world. IEC 60027-2, ratified in 1998 and updated in 2005, formalized the binary prefixes kibi (Ki), mebi (Mi), gibi (Gi), tebi (Ti) and pebi (Pi) so that 1 KiB = 1024 B exactly and 1 KB = 1000 B exactly. IEEE 1541-2002 and ISO/IEC 80000-13:2008 use the same prefixes. Adoption is slow: Linux tools often show "KiB" and "MiB" in df, du or free; Windows Explorer still calls both the binary thing "KB"; hard-drive boxes print "TB" meaning decimal. This tool lets you flip between the two interpretations and see both answers in parallel.
Alternatives
A spreadsheet formula (=A1/1024^3) works fine for one-off binary conversions but does not show both bases side by side. Linux df -h and du -h switch to binary with -H for decimal; macOS df -h is decimal. ls -lh displays binary by default. For network-related sizing (streaming, download ETAs), a bandwidth calculator that multiplies Mbps by duration is closer to the need than this pure unit converter. For filesystem math that includes block-size overhead, a filesystem-specific calculator is more accurate - a 100-byte file still occupies a full 4 KiB block on ext4 by default.
Frequently Asked Questions
Why does my 1 TB drive show as 931 GB in Windows?
Drive makers use decimal (1 TB = 10^12 = 1,000,000,000,000 bytes) while Windows reports binary (1 GB = 2^30 = 1,073,741,824 bytes). Dividing the decimal TB by the binary GB gives 1e12 / 2^30 = 931.32 GB. The storage is correct; only the reported number differs because of the prefix convention. macOS since 2009 uses decimal everywhere so the same drive shows as 1 TB on a Mac.
What is a kibibyte (KiB) and why should I care?
A kibibyte is exactly 1024 bytes - the binary equivalent of the kilobyte. IEC 60027-2 introduced the kibi / mebi / gibi / tebi / pebi prefixes in 1998 so that "KB" could mean 1000 bytes unambiguously (matching SI) and "KiB" could mean 1024 bytes. Linux utilities and many technical documents use the IEC prefixes; Windows Explorer and most consumer software still say "KB" when they mean KiB. When an exact value matters, prefer the IEC form.
Is my input sent anywhere?
No. All conversions happen inside the Preact component in your browser using plain JavaScript arithmetic. There is no network call for the numbers - you can take the tab offline after the page loads and the tool keeps working. Google Analytics records the pageview for aggregate reporting but does not see your input.
How does streaming video consume storage?
Streaming uses bandwidth, not persistent storage, but the same quantity of bytes flows through. A 1080p Netflix stream runs about 3 GB per hour (decimal), a 4K stream about 7 GB per hour. A 10 GB data cap covers roughly 3 hours of 1080p or 1.4 hours of 4K. If you are tethering or on a cellular data plan, this converter lets you translate quickly between provider GB (decimal) and phone-reported GiB (binary).
Why is RAM always in powers of two?
Memory is addressed by binary addresses, and commercial DRAM chips are manufactured in power-of-two die sizes because the address decoder chains cleanly divide by two at each stage. A 16 GB stick really contains 2^34 bytes = 17,179,869,184 bytes = 16 GiB exactly. Operating systems report RAM in binary because there is no physically natural decimal quantity to round to; the stick was made in binary increments by the fab.
How much data is in one Blu-ray?
A single-layer Blu-ray holds 25 GB (decimal), a dual-layer 50 GB, a triple-layer 100 GB (BDXL) and quadruple-layer 128 GB. At 1080p those figures give roughly 9, 18, 36 and 46 hours of high-bitrate video. A 4K Ultra HD Blu-ray is typically a 66 GB dual-layer or 100 GB triple-layer disc. All Blu-ray capacities are quoted in decimal units in the packaging spec.
What is the largest unit on this page?
Petabyte. 1 PB = 10^15 bytes decimal, or 2^50 bytes binary (1 PiB = 1,125,899,906,842,624 bytes). Modern hyperscale data centers routinely manage exabytes (1 EB = 1000 PB). The IEEE specs go further: zetta, yotta, and the 2022 additions ronna and quetta (10^27, 10^30 bytes). Almost no consumer device reaches petabyte scale, but enterprise storage arrays do, and this tool covers the consumer-to-cloud range.
Is 1 Mbps equal to 1 MiB/s for downloads?
No - three factors separate them. First, Mbps is megabits per second (decimal millions of bits); MiB/s is mebibytes per second (binary millions of bytes). Second, a byte is 8 bits. Third, decimal vs binary. A 100 Mbps link, ignoring overhead, transfers at 100,000,000 / 8 = 12,500,000 bytes per second = 11.92 MiB/s. So a 1 GB file takes about 85 seconds on a perfect 100 Mbps pipe.
Why do phones report storage as "available"?
The total flash capacity on the chip is advertised (say 128 GB decimal), but the operating system, system fonts, baseline apps and the filesystem's metadata consume roughly 10-15 GB before the user sees any free space. A "128 GB" iPhone typically shows around 118 GB of user-available storage in Settings, which matches the binary conversion of 128 * 10^9 bytes into GiB minus OS overhead. Apple clarifies this in their capacity disclosure footnotes.
What do KiB, MiB, GiB officially mean?
1 KiB = 2^10 bytes = 1024 B; 1 MiB = 2^20 bytes = 1,048,576 B; 1 GiB = 2^30 bytes = 1,073,741,824 B; 1 TiB = 2^40 bytes; 1 PiB = 2^50 bytes. The definitions come from IEC 60027-2 (1998, updated 2005), reaffirmed in ISO/IEC 80000-13:2008 and IEEE 1541. Using the IEC form removes all ambiguity about whether "KB" meant 1000 or 1024 in a given document.
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