Data Size Converter · Utilities
GiB or GB? Get the exact byte count, both ways.
Type a size — 1.5 GiB, 500 GB, 128 Mb, 500Gi — and see its exact bit and byte count next to every SI and IEC unit. Add a link speed and get the transfer time too, at line rate and at a realistic 90%. Exact integer maths, entirely in your browser.
Runs in your browser — nothing you paste leaves this page. How we prove that
Data size converter playground
Two conventions share the same words: SI (kB, MB, GB) counts in 1000s, IEC (KiB, MiB, GiB) counts in 1024s — that is ISO/IEC 80000-13. Drives are sold in SI; Windows, ls -l and Kubernetes report in IEC.
A bare number means bytes. b is always bits and B always bytes, so 128 Mb is not 128 MB. Kubernetes forms like 500Gi work too.
Results update as you type — press Enter to run now.
A link speed is a line rate in bits per second — the ceiling, not the throughput. 1 Gbps moves at most 125 MB per second, before TCP, TLS and filesystem overhead.
Leave empty to skip the transfer maths. Accepts 1 Gbps, 100 Mb/s, 50 MB/s or 1.5 MiB/s.
Type a size — or tap an example — to see its exact byte count, both unit ladders and how long it takes to move.
The Gap
1000 or 1024 — and 69 GB missing per terabyte.
The industry never settled the question. Disk vendors count in 1000s, so a drive sold as 1 TB holds exactly 1 000 000 000 000 bytes. Windows divides by 1024 and prints 931 GB. Neither is lying, and the support ticket that says "I paid for 1 TB and got 931 GB" is really a units bug — 6.9% of the number, about 69 GB per terabyte.
Ask an LLM and you will get either convention asserted with equal confidence, often in the same answer: 1 TB = 1024 GB in one sentence and 1 TB = 10^12 bytes in the next. The same coin-flip decides whether 500Gi fits a 512 GB disk (it does not: 500Gi is 536.87 GB) and whether 128 Mb is 16 MB or 128 MB.
This converter refuses to guess. It reads what you typed — final b means bits, final B means bytes, an i means 1024 — tells you which convention it landed in, and prints both ladders side by side with the divergence spelled out. Every number is exact integer arithmetic, so 5 YiB shows all 25 digits instead of a float in disguise.
The Pipeline
How it works.
Four deterministic steps turn one short token into an exact byte count, both unit ladders and a transfer window — all inside your browser tab.
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Read the token exactly as written.
Sign, number (with , _ or space groups, . or , decimals, e±N exponents) and unit. The final letter decides everything: b is bits, B is bytes, an i before it means 1024-based.
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Convert to an exact number of bits.
The value becomes a rational number over BigInt — the digits you typed as the numerator, powers of 10 and 1024 as the denominator. No double, no rounding, no 6.044629098073146e24.
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Divide down both ladders.
The same bit count is expressed in every SI unit and every IEC unit, rung by rung, with the divergence between them shown as a percentage. Any value that needs more than six decimals is flagged with ≈.
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Divide by the link speed.
Bits ÷ bits-per-second is the transfer time in seconds — exact, then humanised into days, hours, minutes and seconds. A 90%-of-line-rate row rides alongside it, because line rate is not throughput.
Unit Reference
The whole ladder, both ways.
Eight rungs, two conventions. The gap starts at 2.4% for kilo and compounds to 20.89% by yotta — which is why the unit you write matters more the bigger the number gets.
SI (1000n) ↔ IEC (1024n)
Decimal prefixes on the left, binary prefixes on the right, byte-exact in both columns.
n SI bytes (1000^n) IEC bytes (1024^n) IEC is
1 kB 1 000 KiB 1 024 +2.40%
2 MB 1 000 000 MiB 1 048 576 +4.86%
3 GB 1 000 000 000 GiB 1 073 741 824 +7.37%
4 TB 1 000 000 000 000 TiB 1 099 511 627 776 +9.95%
5 PB 1 000 000 000 000 000 PiB 1 125 899 906 842 624 +12.59%
6 EB 1 000 000 000 000 000 000 EiB 1 152 921 504 606 846 976 +15.29%
7 ZB 1 000 000 000 000 000 000 000 ZiB 1 180 591 620 717 411 303 424 +18.06%
8 YB 1 000 000 000 000 000 000 000 000 YiB 1 208 925 819 614 629 174 706 176 +20.89%Bits, bytes and rates
The other half of the confusion: one letter of case, and a factor of eight.
b = bit B = byte 8 bits = 1 byte
kb = 1000 bits kB = 1000 bytes Kib = 1024 bits KiB = 1024 bytes
100 Mbps = 12.5 MB/s 1 Gbps = 125 MB/s 10 Gbps = 1250 MB/s
128 Mb = 16 MB 1 Kb = 125 bytes 1 Kib = 128 bytes
Kubernetes: 512Mi = 536 870 912 B · 512M = 512 000 000 B · bare K is invalidNext Step
Now size the workload that holds it.
Once you know what 500Gi really is, the next question is usually a manifest: how much memory to request, what limit to set, how many replicas fit the node. The Kubernetes Resource Calculator does that arithmetic in the same binary units — no server, no signup.
1.5 GiB = 1 610 612 736 bytes (1.610613 GB)
1 TB = 1 000 000 000 000 B (931.322575 GiB)
500Gi = 536 870 912 000 bytes (536.87 GB)
128 Mb = 16 000 000 bytes (16 MB)
500 GB over 1 Gbps = 4000 s = 1 h 6 min 40 s
at 90% = 4444.44 s = 1 h 14 min 4 sFAQ
Questions, answered.
Tap a question to expand the answer.
Is 1 TB 1000 GB or 1024 GB?
Both, depending on which unit you mean — and that is exactly the confusion. 1 TB is 1000 GB: the SI prefixes are powers of 1000, so 1 TB = 1 000 000 000 000 bytes. The 1024-based unit has its own name and symbol: 1 TiB (tebibyte) = 1 099 511 627 776 bytes, which is 1024 GiB. So "1 TB = 1024 GB" mixes two systems. If a tool reports 1024-based numbers with SI labels — as Windows does — it is really showing you TiB and calling it TB.
What is the difference between GiB and GB?
A GB (gigabyte) is 10^9 = 1 000 000 000 bytes. A GiB (gibibyte) is 2^30 = 1 073 741 824 bytes. GiB is 7.37% bigger. The IEC prefixes (Ki, Mi, Gi, Ti…) exist precisely so you can say "1024-based" without ambiguity; ISO/IEC 80000-13 standardised them in 2008. Kubernetes, Java, ls -l and most Linux tooling use the binary values; disk vendors, network gear and macOS use the decimal ones.
Why does my 1 TB drive only show 931 GB?
Nothing is missing — two units are being compared. The drive really holds 1 000 000 000 000 bytes (1 TB, SI). Windows divides by 1024 three times and labels the result "GB", giving 931.32 — which is actually 931.32 GiB. A GiB is 1024^3 / 1000^3 = 7.37% larger than a GB, so the count shrinks by about 69 units — 6.9% of the number — for every TB you buy. Paste 1 TB into the converter above and the GiB rung shows 931.322575 directly.
What is the difference between Mb and MB?
Case is the whole difference: a lowercase b means bits, an uppercase B means bytes, and there are 8 bits in a byte. So 128 Mb is 16 MB, and a 100 Mbps link moves at most 12.5 MB/s. Network equipment and ISPs quote bits; files and disks are measured in bytes. This converter never guesses — it reads the final letter exactly as written and tells you which one you asked for.
How do I convert Mbps to MB/s?
Divide by 8. 100 Mbps = 12.5 MB/s, 1 Gbps = 125 MB/s, 10 Gbps = 1250 MB/s. The division is exact because both units are 1000-based; no rounding is involved. Enter the speed in the Link speed field and the tool prints both forms side by side, so you can quote either without doing the arithmetic in your head.
How long does it take to transfer 500 GB over 1 Gbps?
500 GB is 4 000 000 000 000 bits, and 1 Gbps is 1 000 000 000 bits per second, so the line-rate answer is exactly 4000 seconds — 1 h 6 min 40 s. That is the theoretical floor. TCP/IP headers, TLS, filesystem overhead and disk seek time typically cost 5–15%, so the tool also shows the 90%-of-line-rate row: 1 h 14 min 4 s. Quote that one when you are planning a migration window.
What is a kibibyte?
A kibibyte (KiB) is 1024 bytes — the binary counterpart of the kilobyte (kB), which is 1000 bytes. The name is a contraction of "kilo binary byte". Its siblings are the mebibyte (MiB, 1024^2), gibibyte (GiB, 1024^3), tebibyte (TiB), pebibyte (PiB), exbibyte (EiB), zebibyte (ZiB) and yobibyte (YiB). They are the unambiguous way to write 1024-based sizes, and this converter always shows them alongside the SI values.
Why does Kubernetes use Mi and Gi instead of MB and GB?
Because memory is allocated in binary units, and Kubernetes wanted the notation to say so. A resource quantity like 512Mi is 512 × 1024^2 = 536 870 912 bytes, while 512M is 512 × 1000^2 = 512 000 000 bytes — a 7% difference on the same manifest line. Kubernetes accepts a lowercase k for 1000 and Ki/Mi/Gi/Ti/Pi/Ei for the binary set, and rejects a bare uppercase K. This tool parses the Kubernetes forms directly, so you can paste 500Gi and see whether that PVC fits a 512 GB disk (it does not — 500Gi is 536.87 GB).
Does anything I type get uploaded?
No. The conversion is exact BigInt arithmetic running 100% in your browser — there is no server, no account and no logging. The sizes and link speeds you enter never leave your device. The optional Copy link button builds a #q= fragment locally, so even a shared link carries its data in the URL rather than through us.
More free, private DevOps tools.
The Data Size Converter is one tool in OpsCanopy — a growing canopy of browser-based validators, converters and testers that never touch a server.
More in Utilities
39 free tools, every one offline-capable — opscanopy.com works with no signup and nothing uploaded.
Related tools: the Kubernetes Resource Calculator for Mi/Gi requests and limits, the Subnet Calculator and CIDR Checker for address-space maths, or the chmod Calculator — or browse the full tools directory.
Provided as-is for convenience; always confirm capacity and transfer estimates against the device or link you are actually using. OpsCanopy is free and open.