File Size Formatter
Parse any size (1.5 GB, 1500MB, 2 GiB) and see it converted across decimal (KB/MB/GB) and binary (KiB/MiB/GiB) units side by side, with real-world download-time estimates.
About this ToolHow it works, benefits & use casesTap to collapse
A single-field file size converter that clears up the decimal-versus-binary confusion most tools get wrong. Type any human size — "1.5 GB", "1500MB", "2 GiB", or a bare number like "2048" (treated as raw bytes) — and everything updates live as you type, no button to press. The headline shows the value as a best-fit decimal (SI) figure next to its binary (IEC) equivalent, plus the exact byte count with thousands separators. Below that, a side-by-side table lists every unit from bytes up to petabytes in both systems (÷1000 on the left, ÷1024 on the right), so you can read KB and KiB on the same row. A transfer-time estimator shows how long the file would take to download over five connection presets (56k dial-up through 1 Gbps fiber), and a separate picker pins the answer to one unit for copy-paste into specs or configs. The parser is case-insensitive, accepts thousands separators, and treats any unit ending in "iB" as binary. A plain-text report bundles the table and transfer times to copy or download, and the input is preserved in a shareable URL.
How to Use
- 1Type a size in the input — for example "1.5 GB", "1500MB", "2 GiB", or a bare "2048" for raw bytes.
- 2Read the live headline: the decimal (SI) figure, the binary (IEC) figure, and the exact byte count.
- 3Scan the side-by-side table to compare every unit (B through PB / PiB) in both the ÷1000 and ÷1024 systems.
- 4Check the estimated download time across the dial-up, 3G, 4G, broadband, and fiber presets.
- 5Use "Convert to a specific unit" to pin one unit, or copy/download the plain-text report and share the URL.
Key Benefits
- Shows decimal SI (1000-based) and binary IEC (1024-based) units side by side on every row
- Live conversion updates instantly as you type — no Convert button to press
- Accepts mixed input: 1.5 GB, 1500MB, 2 GiB, thousands separators, or a bare byte count
- Distinguishes KB from KiB automatically by the unit suffix, case-insensitively
- Estimates real download time over five bandwidth presets from dial-up to fiber
- Pin-to-unit picker outputs a single clean value for specs, tests, or configs
- Plain-text report copies/downloads cleanly, and the input lives in a shareable URL
Common Use Cases
- Confirming whether a "1 GB" quota means 1,000,000,000 or 1,073,741,824 bytes
- Translating a Content-Length header in bytes into a readable size
- Reconciling disk-tool output (binary) against vendor storage specs (decimal)
- Estimating how long a download or upload will take on a given connection
- Pinning a size to one exact unit literal for a test fixture or config value
Decimal (SI)
1.5 GB
Binary (IEC)
1.4 GiB
Exact bytes
1,500,000,000 B
| 1,500,000,000 B | 1,500,000,000 B |
| 1,500,000 KB | 1,464,843.75 KiB |
| 1,500 MB | 1,430.51 MiB |
| 1.5 GB | 1.397 GiB |
| 0.0015 TB | 0.001364 TiB |
| 0.0000015 PB | 0.000001332 PiB |
Estimated download time
time = (bytes × 8) ÷ connection bandwidth
- 56k Dial-up2d 11h
- 3G (~1.6 Mbps)2h 5m
- 4G (~20 Mbps)10m
- Broadband (100 Mbps)2m
- Fiber (1 Gbps)12 s
The conversion table and transfer times, ready to copy.
File size: 1.5 GB (1.4 GiB) Exact bytes: 1,500,000,000 B Conversion table ───────────────────────────────────────────── Decimal (SI, ÷1000) Binary (IEC, ÷1024) 1,500,000,000 B 1,500,000,000 B 1,500,000 KB 1,464,843.75 KiB 1,500 MB 1,430.51 MiB 1.5 GB 1.397 GiB 0.0015 TB 0.001364 TiB 0.0000015 PB 0.000001332 PiB Estimated download time ───────────────────────────────────────────── 56k Dial-up 2d 11h 3G (~1.6 Mbps) 2h 5m 4G (~20 Mbps) 10m Broadband (100 Mbps) 2m Fiber (1 Gbps) 12 s
Enter a file size
Type any human size. Units are case-insensitive; a bare number is treated as bytes.
Parsed as 1,500,000,000 bytes
Quick examples
Convert to a specific unit
Pin the answer to one unit for copy-paste into specs or configs.
Result
1.5 GB
KB vs KiB — why two columns?
A kilobyte (KB) is 1,000 bytes; a kibibyte (KiB) is 1,024bytes. Disk vendors advertise in decimal (SI) while operating systems often report in binary (IEC), which is why a “500 GB” drive shows up as roughly 465 GiB. Both columns here let you reconcile the two instantly.
Why transfer time matters
Bandwidth is quoted in bits per second, not bytes — so a file's download time is its size in bits (bytes × 8) divided by the connection speed. The estimates above are theoretical maxima; real transfers run slower due to protocol overhead, latency, and congestion.
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Decimal (SI) units use powers of 1000 — 1 KB = 1000 bytes, 1 MB = 1,000,000 bytes — which is how storage vendors and many APIs report sizes. Binary (IEC) units use powers of 1024 with the "i" suffix — 1 KiB = 1024 bytes, 1 MiB = 1,048,576 bytes — which is how most operating systems measure memory and disk. The table shows both side by side so you do not have to guess which convention a number uses.
It keys off the unit suffix. A unit ending in "iB" (KiB, MiB, GiB, TiB, PiB) is treated as binary and multiplied by powers of 1024, while plain units (KB, MB, GB, TB, PB) are decimal and use powers of 1000. Matching is case-insensitive, so "512 mib" and "512 MiB" parse identically, and short aliases like K, M, or G map to the decimal units.