File Size Converter
Convert between bytes, KB, MB, GB and TB
How to use File Size Converter
Convert between bytes, kilobytes, megabytes, gigabytes and terabytes instantly. Free online file size converter tool.
When do you need to convert file sizes?
File sizes appear in contexts ranging from storage management to network transfer planning. Understanding size units helps you make informed decisions about storage, bandwidth, and performance.
- Storage planning: A 2TB hard drive holds roughly 500,000 photos at 4MB each, or about 400 hours of 1080p video at 5GB/hour. Convert to understand storage capacity in real terms.
- Network transfer estimation: How long will it take to upload a 1GB video on a 50Mbps connection? Answer: 1GB = 8Gb ÷ 50Mbps = 160 seconds. Always distinguish between bits and bytes when calculating transfer times.
- Email attachment limits: Gmail allows 25MB attachments; Outlook allows 20MB. Convert your file size before attempting to send.
- App development: Mobile app bundles have size limits (Apple App Store, Google Play) that affect download conversion rates — every MB of app size costs users.
- Database design: Estimate storage requirements for database tables — VARCHAR(255) × rows × columns helps size disk allocation.
Bits vs bytes: Internet speeds are measured in bits per second (Mbps, Gbps). File sizes are measured in bytes (MB, GB). A 100Mbps connection downloads 100 megabits — 12.5 megabytes — per second. Always divide by 8 when converting network speed to file transfer rate.
Frequently Asked Questions
What is the difference between MB and MiB?
MB (megabyte) in the decimal system = 1,000,000 bytes (10^6). MiB (mebibyte) in the binary system = 1,048,576 bytes (2^20). Operating systems historically used MB to mean MiB, causing confusion. Windows still reports file sizes in binary units but labels them MB. macOS switched to decimal in 2009. A '1TB' hard drive has 1,000,000,000,000 bytes — but Windows shows it as ~931GB because it uses binary calculation.
Why does my 1TB drive show less than 1TB available?
Two reasons: (1) The drive manufacturer uses decimal TB (1,000,000,000,000 bytes), but your OS calculates in binary (1,099,511,627,776 bytes per TiB) — so 1TB appears as ~931GB in Windows. (2) The drive firmware and file system reserve space for system use. Both factors reduce apparent capacity.
What is the difference between Mbps and MBps?
Mbps (lowercase b) = megabits per second — used for network and internet speeds. MBps (uppercase B) = megabytes per second — used for file transfer rates and disk speeds. Since 1 byte = 8 bits: 100 Mbps internet = 12.5 MBps download speed. ISPs advertise in Mbps; file managers show progress in MBps.
How much data does streaming video use?
Netflix approximate data usage: SD quality ~1GB/hour, HD (1080p) ~3GB/hour, 4K ~7GB/hour. YouTube HD ~1.5GB/hour. Spotify audio ~40-150MB/hour depending on quality. A 1TB monthly data cap allows roughly 333 hours of HD Netflix streaming.
What is a byte exactly?
A byte is 8 bits — the fundamental unit of digital storage. It can represent 256 different values (2^8). One byte can store one ASCII character, one small integer, or one pixel channel in an 8-bit image. A kilobyte is 1,000 bytes (decimal) or 1,024 bytes (binary). The byte was not always 8 bits — early computers used 6 or 7-bit bytes, but 8-bit became universal in the 1970s.
Decimal (SI) vs binary (IEC) file size units
The decimal system (KB=1,000 bytes, MB=1,000,000 bytes) is used by hard drive manufacturers, network equipment specs, and macOS. The binary system (KiB=1,024 bytes, MiB=1,048,576 bytes) is used by Windows, Linux file systems, and RAM specifications. The IEC standard (2000) introduced the binary prefixes (kibi, mebi, gibi) to eliminate ambiguity, but adoption has been slow. In practice: when buying storage, assume decimal. When your OS reports sizes, assume binary — and expect numbers to look ~7% smaller than advertised.