Convert bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes instantly — with every step shown. Free and exact.
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How many photos fit on a 128 GB phone? Why does a “1 TB” drive show only 931 GB in Windows? Is your 100 Mbps connection really downloading at 100 megabytes per second? Our free Data Storage Converter translates among bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes — showing the two-step working — and this guide explains the famous 1,000 vs 1,024 split behind those confusing numbers.
The single most important idea on this page: a bit (binary digit, 0 or 1) is the smallest unit of digital information, and a byte is 8 bits — enough to store one text character. Everything else is built by multiplying by 1,024 (in the binary convention used by operating systems) or by 1,000 (in the decimal convention used by drive manufacturers). Confusing bits with bytes makes your internet speed look eight times faster than it is; confusing the two conventions makes 70 GB of your “terabyte” drive vanish.
Digital storage is counted in powers of two because computer memory is addressed in binary. One kilobyte is 1,024 bytes (210), one megabyte is 1,024 KB (220), one gigabyte is 1,024 MB (230), one terabyte is 1,024 GB (240), and one petabyte is 1,024 TB (250). This is the convention your operating system uses when it reports free space — which is why the numbers here use 1,024.
The confusion began when storage manufacturers started using decimal prefixes — 1 KB = 1,000 bytes, 1 GB = 1,000,000,000 bytes — because it makes drives sound bigger. A “1 TB” drive holds 1,000,000,000,000 bytes, but Windows divides by 1,024 four times and reports 931 GB. Nobody is cheating; the two sides are just counting with different rulers. To end the ambiguity, the IEC created distinct binary names — kibibyte (KiB), mebibyte (MiB), gibibyte (GiB) — which always mean powers of 1,024, while KB/MB/GB officially mean powers of 1,000. In practice, most software still says “GB” while meaning GiB.
Bits enter the picture with network speeds: ISPs advertise in megabits per second (Mbps), but files are measured in megabytes (MB). Since 1 byte = 8 bits, a 100 Mbps connection downloads at most 12.5 MB/s — before overhead. That factor of eight explains why a “fast” connection still takes minutes to fetch a movie.
Value in target unit = Value in original unit × (bytes per original unit) ÷ (bytes per target unit)
Convert to bytes first, then divide by the byte count of the target unit. This converter uses the binary convention: 1 bit = 0.125 bytes; 1 KB = 1,024 B; 1 MB = 1,048,576 B; 1 GB = 1,073,741,824 B; 1 TB = 1,099,511,627,776 B; 1 PB = 1,125,899,906,842,624 B.
Example 1 — The missing gigabytes: 1 TB drive in GB. Step 1: a decimal terabyte is 1,000,000,000,000 bytes. Step 2: divide by 1,073,741,824 bytes per binary GB: 1,000,000,000,000 ÷ 1,073,741,824 ≈ 931.32 GB. That is exactly what Windows shows — the “missing” 69 GB was never missing, just counted differently.
Example 2 — Download time: 100 Mbps to MB/s. Step 1: 100 megabits × 0.125 bytes/bit = 12.5 megabytes. So 100 Mbps = 12.5 MB/s theoretical maximum. A 5 GB (5,120 MB) game therefore needs at least 5,120 ÷ 12.5 = 409.6 seconds — about 7 minutes — under perfect conditions.
Example 3 — Photo storage: 128 GB phone, 4 MB photos. Step 1: 128 GB × 1,073,741,824 = 137,438,953,472 bytes. Step 2: divide by 4,194,304 bytes per 4 MB photo: 137,438,953,472 ÷ 4,194,304 = 32,768 photos — before the operating system and apps take their share, which is typically 10–15 GB.
Your photo library is 340 GB and you are eyeing a 2 TB cloud plan. Convert: 2 TB = 2 × 1,099,511,627,776 = 2,199,023,255,552 bytes ÷ 1,073,741,824 = 2,048 GB of binary space. Your library uses 340 ÷ 2,048 ≈ 17% of the plan — comfortable headroom for years of growth at typical shooting rates.
A 4K stream needs 25 Mbps sustained. Your household shares a 100 Mbps line among three simultaneous streams: 3 × 25 = 75 Mbps — fine in theory, but convert to bytes to sanity-check a download running alongside: 25 Mbps remaining ÷ 8 = 3.125 MB/s, so a 1 GB file takes 1,024 ÷ 3.125 ≈ 328 seconds. If the video buffers, the math says the line — not the app — is the bottleneck.
In 1956, IBM’s RAMAC 305 — the first commercial hard drive — stored 5 megabytes on fifty 24-inch platters, weighed over a ton, and leased for $3,200 per month (about $35,000 today). Engineers of that era measured capacity in characters and words, not bytes; the 8-bit byte itself was popularized by IBM’s System/360 in 1964, which made it the industry standard.
The floppy disk era made megabytes tangible: a 1981 double-density floppy held 360 KB — this page’s converter shows that as 0.35 MB — and installing Windows 95 required 13 of them. The CD-ROM’s 650 MB (1990s) felt cavernous until DVDs (4.7 GB) and Blu-rays (25 GB) arrived. Flash memory then collapsed the curve: the first 1 GB USB stick (2003) cost about $200; today change buys 128 GB.
The decimal/binary schism dates to this history. Early engineers used “kilobyte” loosely for 1,024 bytes because binary addressing made powers of two natural. When drive marketers adopted decimal prefixes in the 1990s — legally defensible, since “kilo” means 1,000 — the 7% gap at gigabyte scale started generating consumer complaints and even class-action lawsuits. The IEC’s kibibyte/mebibyte/gibibyte standards (1998) were the metrologists’ answer, though everyday language still resists them.
Example 4 — Music library: 8,000 songs at 5 MB each. Total: 8,000 × 5 = 40,000 MB. Convert: 40,000 × 1,048,576 = 41,943,040,000 bytes ÷ 1,073,741,824 = 39.06 GB. A 64 GB phone holds it with room to spare; a 32 GB phone does not.
Example 5 — Backup time: 500 GB over USB 2.0 (480 Mbps). Convert data to bits: 500 GB = 500 × 1,073,741,824 × 8 = 4,294,967,296,000 bits = 4,294,967 Mb. Time: 4,294,967 ÷ 480 ≈ 8,948 seconds ≈ 2.5 hours — and real-world USB 2.0 throughput is roughly half the headline rate, so budget five hours.
Example 6 — Petabyte scale: 1 PB in terabytes. 1 × 1,125,899,906,842,624 ÷ 1,099,511,627,776 = 1,024 TB. Data centers think in these units: a single rack of modern drives can exceed a petabyte, and hyperscale facilities measure in exabytes.
Three related-but-different quantities trip up even technical buyers. Bandwidth (Mbps) is the pipe’s width — how many bits per second the connection can carry. Throughput is what you actually get after protocol overhead, congestion, and Wi-Fi losses — typically 70–90% of bandwidth on a good day. Data caps (GB per month) are the total volume allowed, a completely separate limit: a 100 Mbps line with a 1 TB cap can theoretically move 32 TB monthly, but the cap stops you at 3% of that.
The old unit baud — symbols per second — equals bits per second only for simple two-state signaling; modern modulation packs multiple bits per symbol, so a 2,400-baud modem of the 1980s could carry 9,600 bps. Marketing still exploits the confusion: “gigabit” internet sounds 8× faster than “125 megabyte” internet, but they are the same speed. Whenever a number looks too good, convert it with the tool above — dividing bits by 8 is the great debunker of speed claims.
Example 7 — Monthly cap check: 2 hours of HD streaming daily. HD video ≈ 3 GB/hour. Daily: 6 GB; monthly: 180 GB. On a 1 TB (1,024 GB) cap that is 17.6% — comfortable. Switch to 4K at 15 GB/hour and the same habit needs 900 GB — suddenly the cap matters.
The Data Storage Converter converts among bits, bytes, KB, MB, GB, TB, and PB using the binary convention (1 KB = 1,024 bytes; 1 bit = 0.125 bytes). Formula: target = value × (bytes per from-unit) ÷ (bytes per to-unit). Examples: decimal 1 TB = 931.32 binary GB; 100 Mbps = 12.5 MB/s; 128 GB holds 32,768 four-megabyte photos. Explains decimal vs binary prefixes (KiB/MiB/GiB) and the bits-vs-bytes network speed distinction.
1,024 MB in the binary convention used by operating systems (1 GB = 1,024 × 1,024 × 1,024 bytes). Drive manufacturers quoting decimal units mean 1,000 MB per GB.
The manufacturer counts decimal terabytes (10^12 bytes) while Windows counts binary gibibytes (2^40 bytes). 10^12 ÷ 2^40 ≈ 931.3, so nothing is missing — the units differ.
A bit is a single binary digit (0 or 1). A byte is 8 bits — enough for one text character. Network speeds are quoted in bits (Mbps); file sizes in bytes (MB). Divide bits by 8 to get bytes.
Both, depending on context: 1,024 in the traditional binary convention (kibibyte, KiB), 1,000 in SI decimal usage. The IEC reserves KB for 1,000 and KiB for 1,024, though everyday software mixes them.
About 32,768 photos at 4 MB each (128 × 1,024 ÷ 4), minus 10–15 GB typically consumed by the OS and apps — so roughly 29,000 in practice.
At least 409.6 seconds (about 7 minutes): 5 GB = 5,120 MB = 40,960 Mb; 40,960 ÷ 100 = 409.6 s under perfect conditions, longer with overhead.
A petabyte (1,024 TB), then exabyte (1,024 PB), zettabyte, and yottabyte. Global internet traffic is measured in zettabytes per year.
Use MiB when you mean 1,048,576 bytes (binary) and MB when you mean 1,000,000 bytes (decimal). In casual use “MB” almost always means the binary value on computers.
Cite this page as: Data Storage Converter. Sigma Calculator. Retrieved October 12, 2026, from https://sigmacalculator.net/math-calculators/data-storage-converter/
Last updated: October 12, 2026