Bit per second (bps) - Unit Information & Conversion

Definition

A bit per second (bps or b/s) is the fundamental unit used to measure data transfer rate (also known as bitrate or bandwidth). It quantifies the number of individual bits (the smallest unit of digital information, a 0 or 1) that are transmitted or processed over a communication channel in one second.

History

The concept of measuring data transmission speed in bits per second arose with the advent of digital communications and computing. Early telecommunication systems, like telegraphy and teletypewriters, used related measures like baud rate (symbols per second). As digital technology evolved, focusing on the actual number of bits transferred became more precise and standard, leading to the widespread adoption of bps and its multiples (kbps, Mbps, Gbps) for quantifying network speeds, internet connections, and data throughput.

Common Uses

• Base Unit: Serves as the foundational unit for all other data transfer rate measurements (kbps, Mbps, Gbps, Tbps).
• Low-Speed Communication: Historically used to describe the speeds of early modems (e.g., 300 bps, 1200 bps, 2400 bps).
• Serial Interfaces: Sometimes used to specify the speed of basic serial communication ports (though higher rates are now common).
• Audio/Video Encoding: Bitrates for low-quality audio or specific encoding parameters might be expressed directly in bps or kbps.
• Theoretical Calculations: Used in networking and information theory calculations as the base unit.

Unit FAQs

What is the difference between bps (bits per second) and Bps (Bytes per second)?

• bps (bits per second): Measures the rate of data transfer in individual bits. Network speeds and internet connection bandwidth are almost always advertised in bits per second (or its multiples like Mbps, Gbps).
• Bps (Bytes per second): Measures the rate of data transfer in Bytes (where 1 Byte = 8 bits). File transfer speeds in applications (like web browsers or FTP clients) are often displayed in Bytes per second (or its multiples like KB/s, MB/s). To convert Bps to bps, multiply by 8. To convert bps to Bps, divide by 8. For example, a 100 Mbps internet connection has a theoretical maximum download speed of 12.5 MB/s (100 / 8 = 12.5).

How does bps relate to kbps, Mbps, and Gbps?

These are multiples of bits per second based on SI (decimal) prefixes:

• 1 kbps (kilobit per second) = 1,000 bps
• 1 Mbps (megabit per second) = 1,000 kbps = 1,000,000 bps
• 1 Gbps (gigabit per second) = 1,000 Mbps = 1,000,000,000 bps
• 1 Tbps (terabit per second) = 1,000 Gbps = 1,000,000,000,000 bps

Is bps used for binary prefixes (like kibibits)?

No, data transfer rates almost universally use the standard SI decimal prefixes (kilo, mega, giga). While data storage often involves binary prefixes (kibibyte, mebibyte), data transfer rates stick to the decimal system (kilobit, megabit). So, 1 kbps is always 1000 bps, not 1024 bps.