16-bit

microcomputer A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (P ...

s are microcomputers that use 16-bit

microprocessor A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...

s. A 16-bit register can store 2¹⁶ different values. The

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

integer An integer is the number zero (0), a positive natural number (1, 2, 3, ...), or the negation of a positive natural number (−1, −2, −3, ...). The negations or additive inverses of the positive natural numbers are referred to as negative in ...

values that can be stored in 16 bits depends on the integer representation used. With the two most common representations, the range is 0 through 65,535 (2¹⁶ − 1) for representation as an ( unsigned)

binary number A binary number is a number expressed in the Radix, base-2 numeral system or binary numeral system, a method for representing numbers that uses only two symbols for the natural numbers: typically "0" (zero) and "1" (one). A ''binary number'' may ...

, and −32,768 (−1 × 2¹⁵) through 32,767 (2¹⁵ − 1) for representation as

two's complement Two's complement is the most common method of representing signed (positive, negative, and zero) integers on computers, and more generally, fixed point binary values. Two's complement uses the binary digit with the ''greatest'' value as the ''s ...

. Since 2¹⁶ is 65,536, a processor with 16-bit

memory address In computing, a memory address is a reference to a specific memory location in memory used by both software and hardware. These addresses are fixed-length sequences of digits, typically displayed and handled as unsigned integers. This numeric ...

es can directly access 64 KB (65,536 bytes) of

byte-addressable Byte addressing in hardware architectures supports accessing individual bytes. Computers with byte addressing are sometimes called byte machines, in contrast to ''word-addressable'' architectures, ''word machines'', that access data by word orie ...

memory. If a system uses segmentation with 16-bit segment offsets, more can be accessed. As of 2025, 16-bit microcontrollers cost well under a dollar (similar to close in price legacy 8-bit); the cheapest 16-bit microcontrollers cost less than other types including any 8-bit (and are more powerful, and easier to program generally), making 8-bit legacy microcontrollers not worth it for new applications; 32-bit microcontrollers are also well under half a dollar, cheaper than most 16-bit, with few exceptions, and close to the cheapest 16-bit.

16-bit architecture

The MIT Whirlwind ( 1951) was quite possibly the first-ever 16-bit computer. It was an unusual word size for the era; most systems used

six-bit character code A six-bit character code is a character encoding designed for use on computers with word lengths a multiple of 6. Six bits can only encode 64 distinct characters, so these codes generally include only the upper-case letters, the numerals, some pun ...

and used a word length of some multiple of 6-bits. This changed with the effort to introduce

ASCII ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...

, which used a 7-bit code and naturally led to the use of an 8-bit multiple which could store a single ASCII character or two

binary-coded decimal In computing and electronic systems, binary-coded decimal (BCD) is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits, usually four or eight. Sometimes, special bit patterns are used f ...

digits. The 16-bit word length thus became more common in the 1960s, especially on minicomputer systems. Early 16-bit computers ( 1965–70) include the IBM 1130, the

HP 2100 The HP 2100 is a series of 16-bit minicomputers that were produced by Hewlett-Packard (HP) from the mid-1960s to early 1990s. Tens of thousands of machines in the series were sold over its 25-year lifetime, making HP the fourth-largest minicomp ...

, the

Data General Nova The Nova is a series of 16-bit computing, 16-bit minicomputers released by the American company Data General. The Nova family was very popular in the 1970s and ultimately sold tens of thousands of units. The first model, known simply as "Nov ...

, and the DEC PDP-11. Early

16-bit microprocessors 16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two m ...

, often modeled on one of the mini platforms, began to appear in the 1970s. Examples ( 1973–76) include the five-chip National Semiconductor IMP-16 (1973), the two-chip

NEC is a Japanese multinational information technology and electronics corporation, headquartered at the NEC Supertower in Minato, Tokyo, Japan. It provides IT and network solutions, including cloud computing, artificial intelligence (AI), Inte ...

μCOM-16 (1974), the three-chip Western Digital MCP-1600 (1975), and the five-chip

Toshiba is a Japanese multinational electronics company headquartered in Minato, Tokyo. Its diversified products and services include power, industrial and social infrastructure systems, elevators and escalators, electronic components, semiconductors ...

T-3412 (1976). Early single-chip 16-bit microprocessors ( 1975–76) include the Panafacom MN1610 (1975),

National Semiconductor PACE National Semiconductor's IPC-16A PACE, short for "Processing and Control Element", was the first commercial single-chip 16-bit microprocessor, announced in late 1974. It was a single-chip implementation of their early 1973 five-chip IMP-16 archit ...

(1975),

General Instrument CP1600 The CP1600 is a 16-bit microprocessor created in a partnership between General Instrument and Honeywell, introduced in February 1975. It is one of the first single-chip 16-bit processors. The overall design bears a strong resemblance to the PDP-11 ...

(1975),

Texas Instruments TMS9900 The TMS9900 was one of the first commercially available single-chip 16-bit microprocessors. Introduced in June 1976, it implemented Texas Instruments's TI-990 minicomputer architecture in a single-chip format, and was initially used for low-end ...

(1976), Ferranti F100-L, and the HP BPC. Other notable 16-bit processors include the

Intel 8086 The 8086 (also called iAPX 86) is a 16-bit computing, 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-b ...

, the

Intel 80286 The Intel 80286 (also marketed as the iAPX 286 and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non- multiplexed address and data buses and also the f ...

, the WDC 65C816, and the Zilog Z8000. The

Intel 8088 The Intel 8088 ("''eighty-eighty-eight''", also called iAPX 88) microprocessor is a variant of the Intel 8086. Introduced on June 1, 1979, the 8088 has an eight-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers ...

was

binary compatible Binary-code compatibility (binary compatible or object-code compatible) is a property of a computer system, meaning that it can run the same executable code, typically machine code for a general-purpose computer central processing unit (CPU), ...

with the Intel 8086, and was 16-bit in that its registers were 16 bits wide, and arithmetic instructions could operate on 16-bit quantities, even though its external bus was 8 bits wide. 16-bit processors have been almost entirely supplanted in the

personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...

industry, and are used less than 32-bit (or 8-bit) CPUs in embedded applications.

16/32-bit Motorola 68000 and Intel 386SX

The

Motorola 68000 The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer (CISC) microprocessor, introduced in 1979 by Motorola Semiconductor Products Sector ...

is sometimes called 16-bit because of the way it handles basic arithmetic. The instruction set was based on

32-bit In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in a maximum of 32- bit units. Compared to smaller bit widths, 32-bit computers can perform la ...

numbers and the internal registers were 32 bits wide, so by common definitions, the 68000 is a 32-bit design. Internally, 32-bit arithmetic is performed using two 16-bit operations, and this leads to some descriptions of the system as 16-bit, or "16/32". Such solutions have a long history in the computer field, with various designs performing math even one bit at a time, known as "serial arithmetic", while most designs by the 1970s processed at least a few bits at a time. A common example is the Data General Nova, which was a 16-bit design that performed 16-bit math as a series of four 4-bit operations. 4-bits was the word size of a widely available single-chip ALU and thus allowed for inexpensive implementation. Using the definition being applied to the 68000, the Nova would be a 4-bit computer, or 4/16. Not long after the introduction of the Nova, a second version was introduced, the SuperNova, which included four of the 4-bit ALUs running in parallel to perform math 16 bits at a time and therefore offer higher performance. This was invisible to the user and the programs, which always used 16-bit instructions and data. In a similar fashion, later 68000-family members, starting with the

Motorola 68020 The Motorola 68020 is a 32-bit microprocessor from Motorola, released in 1984. A lower-cost version was also made available, known as the 68EC020. In keeping with naming practices common to Motorola designs, the 68020 is usually referred to as t ...

, had 32-bit ALUs. One may also see references to systems being, or not being, 16-bit based on some other measure. One common one is when the address space is not the same size of bits as the internal registers. Most 8-bit CPUs of the 1970s fall into this category; the

MOS 6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small ...

Intel 8080 The Intel 8080 is Intel's second 8-bit computing, 8-bit microprocessor. Introduced in April 1974, the 8080 was an enhanced successor to the earlier Intel 8008 microprocessor, although without binary compatibility.'' Electronic News'' was a week ...

Zilog Z80 The Zilog Z80 is an 8-bit computing, 8-bit microprocessor designed by Zilog that played an important role in the evolution of early personal computing. Launched in 1976, it was designed to be Backward compatibility, software-compatible with the ...

and most others had 16-bit address space which provided 64 KB of address space. This also meant address manipulation required two instruction cycles. For this reason, most processors had special 8-bit addressing modes, the zero page, improving speed. This sort of difference between internal register size and external address size remained in the 1980s, although often reversed, as memory costs of the era made a machine with 32-bit addressing, 2 or 4 GB, a practical impossibility. For example, the 68000 exposed only 24 bits of addressing on the DIP, limiting it to a still huge (for the era) 16 MB. A similar analysis applies to Intel's 80286 CPU replacement, called the 386SX, which is a 32-bit processor with 32-bit ALU and internal 32-bit data paths with a 16-bit external bus and 24-bit addressing of the processor it replaced.

16-bit application

In the context of

IBM PC compatible An IBM PC compatible is any personal computer that is hardware- and software-compatible with the IBM Personal Computer (IBM PC) and its subsequent models. Like the original IBM PC, an IBM PC–compatible computer uses an x86-based central p ...

and

Wintel Wintel (portmanteau of ''Windows'' and ''Intel'') is the partnership of Microsoft and Intel producing personal computers (PCs) using Intel x86-compatible processors running Windows. Background By the early 1980s, the chaos and incompatibility ...

platforms, a 16-bit application is any software written for

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few op ...

OS/2 OS/2 is a Proprietary software, proprietary computer operating system for x86 and PowerPC based personal computers. It was created and initially developed jointly by IBM and Microsoft, under the leadership of IBM software designer Ed Iacobucci, ...

1.x or early versions of

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

which originally ran on the 16-bit

and

s. Such applications used a 20-

bit The bit is the most basic unit of information in computing and digital communication. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as ...

or 24-bit segment or selector-offset address representation to extend the range of addressable memory locations beyond what was possible using only 16-bit addresses. Programs containing more than 2¹⁶

byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable un ...

s (65,536

s) of instructions and data therefore required special instructions to switch between their 64-kilobyte segments, increasing the complexity of programming 16-bit applications.

List of 16-bit CPUs

* Angstrem ** 1801 series CPU *

Data General Data General Corporation was an early minicomputer firm formed in 1968. Three of the four founders were former employees of Digital Equipment Corporation (DEC). Their first product, 1969's Data General Nova, was a 16-bit minicomputer intended to ...

** Nova **

Eclipse An eclipse is an astronomical event which occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ...

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

PDP-11 The PDP–11 is a series of 16-bit minicomputers originally sold by Digital Equipment Corporation (DEC) from 1970 into the late 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of a ...

(for LSI-11, see Western Digital, below) ***

DEC J-11 The J-11 is a microprocessor chip set that implements the PDP-11 instruction set architecture (ISA) jointly developed by Digital Equipment Corporation and Intersil. It was a high-end chip set designed to integrate the performance and features of ...

*** DEC T-11 * EnSilica ** eSi-1600 *

Fairchild Semiconductor Fairchild Semiconductor International, Inc. was an American semiconductor company based in San Jose, California. It was founded in 1957 as a division of Fairchild Camera and Instrument by the " traitorous eight" who defected from Shockley Semi ...

** 9440 MICROFLAME *

Ferranti Ferranti International PLC or simply Ferranti was a UK-based electrical engineering and equipment firm that operated for over a century, from 1885 until its bankruptcy in 1993. At its peak, Ferranti was a significant player in power grid system ...

** Ferranti F100-L ** Ferranti F200-L *

General Instrument General Instrument (GI) was an American electronics manufacturer based in Horsham, Pennsylvania, specializing in semiconductors and cable television equipment. They formed in New York City in 1923 as an electronics manufacturer. During the 1950s ...

** CP1600 *

Hewlett-Packard The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company. It was founded by Bill Hewlett and David Packard in 1939 in a one-car garage in Palo Alto, California ...

** HP 21xx/2000/1000/98xx/BPC **

HP 3000 The HP 3000 series is a family of 16-bit computing, 16-bit and 32-bit computing, 32-bit minicomputers from Hewlett-Packard. It was designed to be the first minicomputer with full support for time-sharing in the hardware and the operating system, ...

Honeywell Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building automation, industrial automa ...

** Honeywell Level 6/DPS 6 *

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

** 1130/

1800 As of March 1 ( O.S. February 18), when the Julian calendar acknowledged a leap day and the Gregorian calendar did not, the Julian calendar fell one day further behind, bringing the difference to 12 days until February 28 ( O.S. February 16), ...

** System/7 ** Series/1 ** System/36 *

Infineon Infineon Semiconductor solutions is the largest microcontroller manufacturer in the world, as well as Germany's largest semiconductor manufacturer. It is also the leading automotive semiconductor manufacturer globally. Infineon had roughly 58,0 ...

** XE166 family ** C166/C167 family ** XC2000 *

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

Intel 80186 The Intel 80186, also known as the iAPX 186, or just 186, is a microprocessor and microcontroller introduced in 1982. It was based on the Intel 8086 and, like it, had a 16-bit external Bus (computing)#Address bus, data bus multiplexed with a 20 ...

/ Intel 80188 **

Intel MCS-96 The Intel MCS-96 is a family of microcontrollers (MCU) commonly used in embedded systems. The family is often referred to as the 8xC196 family, or 80196, the most popular MCU in the family. These MCUs are commonly used in hard disk drives, modems, ...

* Lockheed ** MAC-16 * MIL-STD-1750A *

Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been ...

** Motorola 68HC12 ** Motorola 68HC16 *

National Semiconductor National Semiconductor Corporation was an United States of America, American Semiconductor manufacturing, semiconductor manufacturer, which specialized in analogue electronics, analog devices and subsystems, formerly headquartered in Santa Clara, ...

IMP-16 The IMP-16, by National Semiconductor, was the first multi-chip 16-bit computing, 16-bit microprocessor, released in 1973. It consisted of five PMOS logic, PMOS integrated circuits: four identical RALU chips, short for Processor register, regist ...

** PACE/INS8900 *

** μCOM-16 ** NEC V20 and V30 * Panafacom ** MN1610 * Renesas ** Renesas (16-bit registers, 24-bit address space) *

Ricoh is a Japanese multinational imaging and electronics company. It was founded by the now-defunct commercial division of the Institute of Physical and Chemical Research (Riken) known as the ''Riken Concern'', on 6 February 1936 as . Ricoh's hea ...

** Ricoh 5A22 (WDC 65816 clone used in

SNES The Super Nintendo Entertainment System, commonly shortened to Super Nintendo, Super NES or SNES, is a 16-bit home video game console developed by Nintendo that was released in 1990 in Japan, 1991 in North America, 1992 in Europe and Oceania an ...

) *

Texas Instruments Texas Instruments Incorporated (TI) is an American multinational semiconductor company headquartered in Dallas, Texas. It is one of the top 10 semiconductor companies worldwide based on sales volume. The company's focus is on developing analog ...

** TI MSP430 *

** T-3412 *

Western Design Center The Western Design Center (WDC), located in Mesa, Arizona, is a company that develops intellectual property for, and licenses manufacture of, MOS Technology 65xx based microprocessors and microcontrollers. WDC was founded in 1978 by a former ...

** WDC 65816/65802 *

Western Digital Western Digital Corporation is an American data storage company headquartered in San Jose, California. Established in 1970, the company is one of the world's largest manufacturers of hard disk drives (HDDs). History 1970s Western Digital ...

MCP-1600 The MCP-1600 is a multi-chip 16-bit microprocessor introduced by Western Digital in 1975 and produced through the early 1980s. Used in the Pascal MicroEngine, the WD16 processor in the Alpha Microsystems AM-100, and the DEC LSI-11 microcom ...

*** used in the DEC LSI-11 *** used in the Pascal MicroEngine *** used in the WD16 *

Xerox Xerox Holdings Corporation (, ) is an American corporation that sells print and electronic document, digital document products and services in more than 160 countries. Xerox was the pioneer of the photocopier market, beginning with the introduc ...

Alto The musical term alto, meaning "high" in Italian (Latin: '' altus''), historically refers to the contrapuntal part higher than the tenor and its associated vocal range. In four-part voice leading alto is the second-highest part, sung in ch ...

Zilog Zilog, Inc. is an American manufacturer of microprocessors, microcontrollers, and application-specific embedded System on a chip, system-on-chip (SoC) products. The company was founded in 1974 by Federico Faggin and Ralph Ungermann, who were soo ...

** Zilog Z8000 ** Zilog Z280

References

{{Authority control

16-bit 16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two ...

16-bit architecture

16/32-bit Motorola 68000 and Intel 386SX

16-bit application

List of 16-bit CPUs

See also

References