How many GiB is 1 GB?

1 GB (gigabyte, SI decimal) equals 10⁹ ÷ 2³⁰ ≈ 0.931322574615 GiB. In other words, one gigabyte is slightly less than one gibibyte.

What is the difference between GB and GiB?

GB follows the SI decimal system: 1 GB = 1,000,000,000 bytes (10⁹). GiB follows the IEC binary system: 1 GiB = 1,073,741,824 bytes (2³⁰). The binary unit is about 7.37% larger, which is why an OS always reports less than the advertised gigabyte count.

Why does my 1,000 GB drive show as 931 GiB in Windows?

Storage manufacturers measure capacity in decimal GB (powers of 1,000). Windows, macOS, and Linux report usage in binary GiB (powers of 1,024). 1,000 GB × (10⁹ ÷ 2³⁰) ≈ 931.32 GiB — no capacity is lost, it is simply reported in a different unit.

How do I convert gigabytes to gibibytes?

Multiply the GB value by 1,000,000,000 (10⁹) to get bytes, then divide by 1,073,741,824 (2³⁰). Or simply multiply GB by 0.931322574615. Example: 256 GB × 0.931322574615 ≈ 238.42 GiB.

Does this conversion lose any data?

No. Converting between GB and GiB is a unit change only — like converting kilometers to miles. The actual byte count of the storage or file does not change.

Gigabytes to Gibibytes Converter

Enter gigabytes (GB) and get gibibytes (GiB) instantly — with the full calculation breakdown and a side-by-side comparison explaining why OS-reported sizes differ from advertised storage.

Input — Gigabytes (GB)

Number of gigabytes

Conversion factor: 1 GB = 10⁹ bytes; 1 GiB = 2³⁰ bytes. Therefore 1 GB = 10⁹ ÷ 2³⁰ ≈ 0.931322574615 GiB.

Results

Enter a gigabyte value and click Convert.

Reference Table — Common GB Values in GiB

Typical storage capacities as advertised (GB) vs. OS-reported (GiB).

GB (advertised)	GiB (OS-reported)	Bytes	Typical device

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Summary

This tool converts gigabytes (GB, decimal SI) into gibibytes (GiB, binary IEC). 1 GB equals exactly 10⁹ bytes; 1 GiB equals 2³⁰ = 1,073,741,824 bytes. Because 10⁹ ÷ 2³⁰ ≈ 0.931322574615, each advertised gigabyte works out to slightly less than one gibibyte. Storage manufacturers use GB (powers of 1,000) while operating systems report disk and file sizes in GiB (powers of 1,024) — this ~6.87% gap is why a 1,000 GB drive appears as roughly 931 GiB in Windows, macOS, or Linux.

How it works

Enter the number of gigabytes (GB) in the input field.
The tool multiplies by 10⁹ to get bytes, then divides by 2³⁰ to get gibibytes.
The calculation steps panel shows the full formula with your values substituted in.
The comparison card shows the original GB value alongside the converted GiB value.
Use the copy button to grab the GiB result for use elsewhere.
Check the reference table for common GB values and their GiB equivalents.

Use cases

Understand why a 500 GB SSD shows as ~466 GiB in Windows or macOS.
Convert cloud storage quotas from GB (advertised) to GiB (OS-reported).
Cross-check backup sizes when tools report in GB but dashboards display GiB.
Verify that a 256 GB phone's usable space matches what the OS shows.
Explain the SI vs IEC gap to clients reading storage specs and disk reports.
Quick capacity planning when mixing GB specs with GiB limits in infrastructure configs.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu