--- title: "GB to GiB converter: Mac storage units explained" description: "Convert between GB, MB and TB (decimal, used by Finder) and GiB, MiB and TiB (binary, used by du -h), and see why your Mac and Terminal show different sizes." url: https://tidymac.space/tools/storage-unit-converter/ updated: 2026-10-16 --- [Home](/) [Tools](/tools/) GB to GiB storage unit converter # GB to GiB converter for Mac storage 1 GB is 1,000,000,000 bytes; 1 GiB is 1,073,741,824 bytes, about 7.4% more. Finder uses GB, while `du -h` in Terminal uses GiB and labels it “G”. Convert any size below. Updated October 16, 2026By the Tidy Mac team Convert Size UnitMB (decimal)GB (decimal)TB (decimal)MiB (binary)GiB (binary)TiB (binary) Unit Value System MB 10,737.4182 Decimal (Finder, drive makers) GB 10.7374 Decimal (Finder, drive makers) TB 0.010737 Decimal (Finder, drive makers) MiB 10,240 Binary (du -h, df -h) GiB 10 Binary (du -h, df -h) TiB 0.009766 Binary (du -h, df -h) \= 10,737,418,240 bytes ![](/img/brand/tidy-128.png) ### See your storage in plain numbers Tidy Mac measures your storage in the same decimal units Finder uses, counts APFS clones once, and adds up to what Disk Utility reports. $9.99 once, 2 Macs. [Download](/download/TidyMac.dmg) [Buy for $9.99 once](/buy/) ## How it works Every value is converted to bytes and then divided by the size of each unit. Decimal units step by 1,000 (MB → GB → TB). Binary units step by 1,024 (MiB → GiB → TiB), so the gap grows with size: 2.4% at the KB level, 4.9% at MB, 7.4% at GB and almost 10% at TB. **Why the numbers differ.** Drive makers and macOS Finder use decimal units, defined by the International System of Units. Many command-line tools, including `du -h` and `df -h` on a Mac and many Linux tools, count in binary units but print them with the same letters (G, GB). The IEC created the names KiB, MiB, GiB and TiB to tell them apart. No space is lost; it’s the same number of bytes written two ways. See [checking disk space in Terminal](/guides/check-disk-space-mac-terminal/) for which command uses which. ## Questions Is 1 GB 1,000 MB or 1,024 MB? In the decimal (SI) system that Finder and drive makers use, 1 GB = 1,000 MB = 1,000,000,000 bytes. The binary unit, 1 GiB, is 1,024 MiB = 1,073,741,824 bytes. Many tools write “GB” or “G” when they mean GiB, which is where the confusion comes from. Why does my 1 TB drive show as 931 GB? It doesn’t on a Mac: Finder counts in decimal units, so a 1 TB drive shows close to 1,000 GB of capacity. Tools that count in binary units show 1 TB (1,000,000,000,000 bytes) as about 931 GiB, often labelled “931 GB”. Which units does du use on a Mac? `du -h` and `df -h` use binary units and print them as K, M, G and T. `df -H` uses decimal units like Finder. So a folder du shows as 10G is about 10.7 GB in Finder. Which units does macOS use? Finder, Get Info and System Settings › Storage have used decimal units (1 GB = 1,000,000,000 bytes) since Mac OS X 10.6 Snow Leopard. ## Related [Check disk space from TerminalGuide](/guides/check-disk-space-mac-terminal/)[What is purgeable space?Guide](/guides/purgeable-space-mac/)[What is System Data?Library](/learn/what-is-system-data-on-mac/)[What is /private/var/vm?Folder](/folders/private-var-vm/)[Mac battery health checkerFree tool](/tools/mac-battery-health/)[Mac memory usage explainerFree tool](/tools/mac-memory-usage/)