Byte Size Converter
Convert B / KB / MB / GB / TB / PB with IEC (1024) and SI (1000) standards side by side.
published
- [FREE]
- [NO_SIGNUP]
- [NO_UPLOAD]
A byte size converter translates between B, KB, MB, GB, TB, and PB under either IEC (1024-based) or SI (1000-based) conventions.
When to use which standard
| Context | Use | Why |
|---|---|---|
| RAM, file size in OS, filesystem block | IEC (KiB, MiB, GiB) | All powers of 1024 by hardware design |
| Disk capacity on the box | SI (KB, MB, GB) | Drive vendors count powers of 1000 |
| Network bandwidth | SI | Bits per second multiplied by 1000s |
| Cloud egress billing | SI typically | Check the provider’s exact definition |
Related tools
- Download time calculator — pair with bandwidth.
- Hash Generator — fingerprint a file by content, not size.
Frequently asked questions
IEC vs SI — which one is right?
Both, depending on context. IEC (KiB, MiB, GiB) is powers of 1024 — what RAM, filesystems, and operating systems mean. SI (KB, MB, GB) is powers of 1000 — what disk vendors advertise on the box and what network speeds use. The 1 TB drive you buy is 1×10^12 bytes; the OS shows ~931 GiB.
Why does my 1 TB drive show as 931 GB in the OS?
Because the drive maker counts 1 TB = 10^12 bytes (SI), but the OS counts 1 GiB = 2^30 bytes (IEC, mislabeled as "GB" in Windows). 10^12 / 2^30 ≈ 931.32. Same bytes, different display.
Privacy?
Pure JS math. No upload.