Calculators

GB to GiB Converter

Convert bits and bytes with SI decimal prefixes or IEC binary kibibytes and tebibytes.

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About this tool

Storage and data-size figures appear in everyday computing, networking, and purchasing decisions — yet the units that describe them are surprisingly inconsistent. Drive manufacturers advertise capacity in decimal units where 1 GB equals exactly one billion bytes, but operating systems often display the same drive using binary units where 1 GiB equals 1,073,741,824 bytes. That 7% gap is why a brand-new 1 TB drive shows up as roughly 931 GiB. This converter covers bits, bytes and the four main prefixes in either system. Leave the IEC binary box unticked to convert between bits, bytes, KB, MB, GB and TB using powers of 1,000, or tick it to switch the lists to KiB, MiB, GiB and TiB using powers of 1,024. Choose the From and To units and the result appears instantly to fourteen significant digits. To compare the two systems, convert to bytes in one mode and then from bytes in the other.

Why use it

  • Decimal or Binary on Demand: One checkbox switches between SI units (KB = 1,000 bytes) and IEC units (KiB = 1,024 bytes), and the result label always states which multiplier was used, so you know which figure a vendor or OS is quoting.

  • Bits and Bytes: Bits are in both unit lists, so you can turn a bandwidth figure into bytes — 100,000,000 bits is 12.5 MB — or the reverse.

  • Live Conversion: The result updates on every keystroke or unit change without a page reload, which is handy when checking whether a file or backup fits a storage tier.

  • Precise Results: Values carry up to fourteen significant digits, so large byte counts such as 1,099,511,627,776 for one TiB are shown exactly.

  • Offline, No Account Needed: Every conversion is browser-side arithmetic. No data is uploaded, no sign-in is required, and the tool works without a live internet connection once the page has loaded.

How to use

  1. Tick IEC binary for KiB, MiB, GiB and TiB, or leave it unticked for decimal KB, MB, GB and TB
  2. Type the numeric value you want to convert into the Value field
  3. Choose the source unit in the From dropdown — Bits, Bytes or a prefixed unit
  4. Choose the target unit in the To dropdown
  5. Read the result and the ×1000 or ×1024 note under it, which update in real time

When it helps

  • When a newly purchased hard drive or SSD shows a smaller capacity than advertised after formatting
  • When converting a broadband bit rate into bytes to estimate download speed
  • When sizing cloud storage tiers and needing to compare decimal and binary capacities correctly
  • When a developer needs to convert API response sizes or message queue limits between bits and bytes
  • When planning backup storage and reconciling OS-reported sizes with vendor-listed capacities

Examples

Why 1 TB shows as 931 GiB

Input

Decimal: 1 Terabytes → Bytes = 1000000000000; then IEC: 1000000000000 Bytes → Gibibytes

Expected result

931.32257461548 GiB

Broadband speed

Input

Decimal: 100000000 Bits (100 Mbps) → Megabytes

Expected result

12.5 MB (per second)

TiB in bytes

Input

IEC: 1 Tebibytes → Bytes

Expected result

1099511627776 bytes

Tips

  • Hard drives are advertised in decimal (1 TB = 10¹² bytes) but operating systems display binary (TiB), which is why a '1 TB' drive appears as ~931 GiB after formatting
  • Network bandwidth is always in bits per second; file-transfer speed is in bytes per second — divide Mbps by 8 to get the MB/s download rate
  • RAM uses binary units internally, so a '16 GB' stick is technically 16 GiB — powers of two all the way down
  • The decimal/binary gap compounds with scale: 1% at KB, 5% at MB, 7% at GB, 10% at TB
  • Use IEC prefixes (KiB, MiB, GiB) when writing technical documentation or contracts where ambiguity could be costly

Frequently Asked Questions

What is the difference between MB and MiB?
MB (megabyte) in the SI/decimal system equals exactly 1,000,000 bytes. MiB (mebibyte) in the IEC binary system equals 1,048,576 bytes (2²⁰). The difference is about 4.9% and grows at higher prefixes, reaching roughly 7% at GB/GiB and nearly 10% at TB/TiB.
Why does my 1 TB drive show as roughly 931 GB in Windows?
Drive manufacturers define 1 TB as 1,000,000,000,000 bytes (decimal). Windows and Linux display storage in binary units (GiB) but label them 'GB'. Dividing 10¹² by 2³⁰ gives approximately 931.3 GiB, which is displayed as 931 GB.
What is the difference between Mbps and MB/s?
Mbps stands for megabits per second (used for network speeds), while MB/s stands for megabytes per second (used for file-transfer rates). Since one byte contains 8 bits, divide Mbps by 8 to find MB/s. A 100 Mbps connection has a theoretical peak download rate of 12.5 MB/s.
Are GB and GiB interchangeable in everyday use?
Informally they are often treated as the same, but they differ by 7.4%. For most casual purposes the distinction is minor, but for storage purchasing, backup planning, or billing by the gigabyte, the gap is large enough to matter and should be verified explicitly.
How many bytes are in a kilobyte?
In the decimal (SI) system, 1 KB equals 1,000 bytes. In the binary (IEC) system, 1 KiB equals 1,024 bytes. Most consumer software historically used 1,024, but modern storage and networking standards increasingly use 1,000. Always check which system the source is using.
Why is network speed measured in bits rather than bytes?
Network protocols transmit data one bit at a time at the physical layer, so bandwidth is naturally expressed in bits per second. Marketing adopted bits because the numbers look eight times larger than the equivalent byte-per-second figure. The confusion is intentional in some respects.
How big is a petabyte?
One petabyte (PB) equals 1,000 terabytes or 10¹⁵ bytes in the decimal system. One pebibyte (PiB) equals 1,024 tebibytes or 2⁵⁰ bytes. To put it in context, the US Library of Congress print collection is estimated at roughly 10 TB — a petabyte is 100 times that.
What unit do RAM and solid-state storage use?
RAM is manufactured and addressed in powers of two, so it uses binary units: a 16 GB RAM stick is actually 16 GiB. Consumer SSDs and hard drives use decimal units in marketing but are physically addressed in binary by the OS, causing the apparent size discrepancy.

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Glossary

Bit
The smallest unit of digital information, representing a binary 0 or 1. Network speeds are typically quoted in bits per second (bps, Kbps, Mbps, Gbps).
Byte
A group of 8 bits, the fundamental unit of addressable memory and file size. File sizes and storage capacities are measured in bytes and their multiples.
Kilobyte vs Kibibyte (KB vs KiB)
KB (kilobyte) equals 1,000 bytes in the SI decimal system. KiB (kibibyte) equals 1,024 bytes in the IEC binary system. The 2.4% difference is small but compounds at higher prefixes.
Megabyte vs Mebibyte (MB vs MiB)
MB equals 1,000,000 bytes; MiB equals 1,048,576 bytes. The roughly 4.9% difference means that a file reported as 100 MB by a decimal system is closer to 95.4 MiB in binary.
Gigabyte vs Gibibyte (GB vs GiB)
GB equals 10⁹ bytes; GiB equals 2³⁰ bytes (1,073,741,824). The 7.4% difference is the most commonly encountered source of confusion in consumer storage advertising.
Bit Rate (Mbps vs MB/s)
Mbps (megabits per second) measures network transmission speed. MB/s (megabytes per second) measures data-transfer throughput. Converting between them requires dividing or multiplying by 8.
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