Exact Bytes
1
Convert File Size Units
Enter a file size in any common bit or byte unit. The calculator converts it instantly, shows decimal and binary interpretations, and estimates transfer time.
Applies to KB, MB, GB, TB and Kb, Mb, Gb, Tb. IEC units (KiB, MiB, GiB, TiB) always use 1024.
Normalized Size
1 B
8 b
Exact Bits
8
Est. Transfer Time
0.08s
Capacity Fit
137,438,953,472 files
Remaining space: 0 B
| Unit | Value | Bit Equivalent | Notes |
|---|
About This Tool
File size math is simple in theory but confusing in practice because there are two competing unit systems. Decimal storage units use powers of 1000 (KB, MB, GB), while binary units use powers of 1024 (KiB, MiB, GiB). Manufacturers often advertise drive capacity in decimal units, but operating systems may display values in binary units. This tool shows both so you can compare them directly from one input.
The calculator converts everything through bytes, then expands into common units for quick inspection. It also includes bit conversions, because network speeds are usually expressed in bits per second while files are measured in bytes. If you set a transfer speed, the tool estimates download or upload duration and shows a file-fit estimate for a selected storage capacity. That makes it useful for planning backups, media libraries, and deployment packages.
Formula
bytes = input × unitMultiplier
bits = bytes × 8
time (seconds) = bits / bitsPerSecond
For decimal units, multiplier uses 1000^n (or 1024^n if Binary mode is selected). IEC units such as MiB always use 1024^n.
Quick Reference
| Unit | Bytes | Bits |
|---|---|---|
| 1 KB | 1,000 | 8,000 |
| 1 KiB | 1,024 | 8,192 |
| 1 MB | 1,000,000 | 8,000,000 |
| 1 MiB | 1,048,576 | 8,388,608 |
| 1 GB | 1,000,000,000 | 8,000,000,000 |
| 1 GiB | 1,073,741,824 | 8,589,934,592 |
Binary File Size Calculator FAQ
Why does 1 TB drive show less than 1 TB in some systems?
Drive labels usually use decimal TB, but many systems present binary TiB-style values. A decimal 1 TB device is about 0.91 TiB.
Should I use decimal or binary mode for downloads?
Use whichever unit your source uses. ISPs and transfer speeds are typically decimal bits per second, while OS file displays are often binary bytes.
Can I use this for cloud storage planning?
Yes. Enter typical file size, choose your provider's unit style, and use the capacity-fit result to estimate file count and leftover space.
Does this tool upload my data?
No. All calculations run in your browser only.
Why do network speeds use bits but file sizes use bytes?
Network protocols historically measured throughput in bits per second. File systems measure storage in bytes. To convert a network speed to file transfer rate, divide bits per second by 8. A 100 Mbps connection transfers about 12.5 MB per second.
What is the difference between KB and KiB?
KB (kilobyte) uses base-10 and equals 1,000 bytes. KiB (kibibyte) uses base-2 and equals 1,024 bytes. The IEC introduced KiB, MiB, and GiB to remove ambiguity. The same pattern applies to MB vs MiB, GB vs GiB, and TB vs TiB.
How much smaller does a 1 TB drive appear in a binary-based OS?
A 1 TB drive (1,000,000,000,000 bytes) shows as about 931 GiB in a binary-based display. The 7% difference grows with larger drives -- a 4 TB drive appears as roughly 3.64 TiB.
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Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are computed using standard formulas and should be verified for critical applications.
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Binary File Size Calculator FAQ
What is the difference between MB and MiB?
MB is decimal and uses powers of 1000. MiB is binary and uses powers of 1024. So 1 MiB equals 1,048,576 bytes, while 1 MB equals 1,000,000 bytes.
Why do drive sizes and OS file sizes look different?
Storage vendors usually advertise decimal units such as GB and TB, while operating systems often display binary units like GiB and TiB. The same byte count appears smaller when shown in binary-labeled terms.
Is this calculator private?
Yes. All math runs locally in your browser. No file or usage data is uploaded.
How do I convert bits to bytes?
Divide bits by 8 to get bytes. Multiply bytes by 8 to get bits.
Why do network speeds use bits but file sizes use bytes?
Network protocols historically measured throughput in bits per second. File systems measure storage in bytes. To convert a network speed to file transfer rate, divide bits per second by 8. A 100 Mbps connection transfers about 12.5 MB per second.
What is the difference between KB and KiB?
KB (kilobyte) uses base-10 and equals 1,000 bytes. KiB (kibibyte) uses base-2 and equals 1,024 bytes. The IEC introduced KiB, MiB, and GiB to remove ambiguity. The same pattern applies to MB vs MiB, GB vs GiB, and TB vs TiB.
How much smaller does a 1 TB drive appear in a binary-based OS?
A 1 TB drive (1,000,000,000,000 bytes) shows as about 931 GiB in a binary-based display. The 7% difference grows with larger drives -- a 4 TB drive appears as roughly 3.64 TiB.