ENIAC Performance Calculator

Estimate the computational power and energy consumption of the first electronic computer compared to modern systems

ENIAC: The First Electronic Computer in History

The ENIAC (Electronic Numerical Integrator and Computer) at the University of Pennsylvania’s Moore School of Electrical Engineering. Photo: U.S. Army

The Electronic Numerical Integrator and Computer (ENIAC) represents one of the most significant milestones in computing history. Completed in 1945 at the University of Pennsylvania’s Moore School of Electrical Engineering, ENIAC was the first general-purpose electronic computer, marking the transition from mechanical to electronic computing.

Historical Context and Development

ENIAC was developed during World War II (1943-1945) as part of a secret military project known as “Project PX.” The primary motivation was to calculate artillery firing tables for the U.S. Army’s Ballistic Research Laboratory. Before ENIAC, these calculations were performed by teams of human “computers” (mostly women) using mechanical desk calculators—a process that could take up to 40 hours for a single trajectory.

• Funding: $486,804.22 (equivalent to about $7.5 million in 2023)
• Development time: 30 months (1943-1945)
• First operation: November 1945 (officially dedicated February 15, 1946)
• Decommissioned: October 2, 1955

Technical Specifications

ENIAC’s technical specifications were revolutionary for its time but seem primitive by modern standards:

Component	Specification	Modern Equivalent
Weight	30 tons (27,216 kg)	0.0002 kg (Raspberry Pi 4)
Size	100 ft × 30 ft × 8.5 ft (30.5 m × 9.1 m × 2.6 m)	85.6 mm × 53.9 mm × 6.1 mm (iPhone 14)
Power Consumption	150 kW	5-10 W (smartphone)
Vacuum Tubes	17,468	0 (replaced by transistors)
Relays	7,200	0 (electronic switching)
Resistors	70,000	Millions (integrated circuits)
Capacitors	10,000	Billions (modern chips)
Clock Speed	100 kHz	3-5 GHz (modern CPUs)
Memory	20 accumulators (10-digit decimal)	16GB+ RAM (typical 2023 computer)

Performance Characteristics

ENIAC’s performance was groundbreaking for 1945 but illustrates how far computing has advanced:

• Addition time: 200 microseconds (0.0002 seconds)
• Multiplication time: 2.8 milliseconds (0.0028 seconds)
• Division time: 24 milliseconds (0.024 seconds)
• Square root time: 162 milliseconds (0.162 seconds)
• Operations per second: ~5,000 additions or 357 multiplications
• Programming: Physical rewiring (could take days)

For comparison, a modern smartphone can perform billions of operations per second while consuming less power than a household light bulb. The Computer History Museum provides excellent documentation of ENIAC’s capabilities versus modern systems.

The ENIAC Programmers

One of the most important but initially overlooked aspects of ENIAC was the role of its programmers. Six women—Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas, and Ruth Lichterman—were responsible for developing the programming techniques that made ENIAC functional. Their work laid the foundation for modern computer programming.

The ENIAC programmers (left to right): Kay McNulty, Frances Bilas, Betty Jennings, Ruth Lichterman, Betty Snyder, and Marlyn Wescoff. Photo: U.S. Army

These women had to develop programming concepts from scratch, including:

1. Subroutines (before the term existed)
2. Nested loops
3. Indirect addressing
4. Debugging techniques

Their contributions were largely unrecognized for decades, reflecting the gender biases of the time. The ENIAC Programmers Project works to preserve their legacy.

Impact and Legacy

ENIAC’s impact on computing and society includes:

• Proving electronic computing was viable: Before ENIAC, many scientists doubted that electronic components could be reliable enough for complex calculations.
• Inspiring subsequent computers: ENIAC’s success led directly to EDVAC, EDSAC, and the stored-program concept that defines modern computers.
• Accelerating scientific research: After the war, ENIAC was used for weather prediction, atomic energy calculations, and other scientific applications.
• Establishing computer science: The challenges of programming ENIAC helped create computer science as an academic discipline.

ENIAC’s Influence on Subsequent Computers

Computer	Year	Key Improvement Over ENIAC	Performance Gain
EDVAC	1949	Stored-program architecture	10× faster programming
UNIVAC I	1951	Commercial availability, magnetic tape storage	5× smaller, more reliable
IBM 701	1952	Vacuum tube reliability improvements	2× faster operations
TX-0	1956	Transistor-based (no vacuum tubes)	100× more reliable
PDP-1	1959	First commercial transistorized computer	1/100th the size of ENIAC

ENIAC in Popular Culture

ENIAC has appeared in various media, reflecting its cultural significance:

• Film: Featured in “The Computer Wore Tennis Shoes” (1969) and “Race to Build the Atomic Bomb” (documentary)
• Literature: Central to Neal Stephenson’s “Cryptonomicon” (1999)
• Music: Referenced in They Might Be Giants’ song “The Mesopotamians” (2004)
• Video Games: Appears in “Call of Duty: Black Ops” (2010) and “Assassin’s Creed: Syndicate” (2015)

Preservation and Exhibits

Portions of ENIAC have been preserved and are on display at several institutions:

• Smithsonian Institution: Several panels and components at the National Museum of American History in Washington, D.C.
• University of Pennsylvania: One of the original accumulators and other components
• Computer History Museum: Replica and original documentation in Mountain View, California
• U.S. Army Ordnance Museum: Some components related to its military applications

The Smithsonian’s ENIAC collection provides detailed information about the preserved components and their historical context.

ENIAC’s Technical Limitations

While revolutionary, ENIAC had several significant limitations:

1. Programming via patch cables: Reprogramming could take days as operators physically rewired the machine.
2. No stored program: Instructions were part of the physical setup rather than stored in memory.
3. Limited memory: Only 20 accumulators for storage, each holding a 10-digit decimal number.
4. Reliability issues: With 17,468 vacuum tubes, tube failures were common (about 2 per day).
5. Heat generation: Required industrial cooling systems to prevent overheating.
6. Physical size: Occupied 1,800 square feet (167 m²) of floor space.

Modern Recreations and Simulations

Several projects have recreated ENIAC in various forms:

• ENIAC-on-a-Chip: A 1996 project by the University of Pennsylvania that recreated ENIAC’s functionality on a single chip (7.44 mm × 5.29 mm).
• Software Simulators: Multiple software emulators exist that can run original ENIAC programs.
• FPGA Implementations: Field-programmable gate array versions have been created for educational purposes.
• LEGO Model: A functional LEGO model was built in 2011 using 50,000 bricks.

These recreations help modern engineers understand the challenges faced by ENIAC’s developers and appreciate how far computing has advanced.

ENIAC’s Enduring Influence on Modern Computing

While ENIAC itself was decommissioned in 1955, its influence persists in several key areas:

Architectural Innovations

ENIAC introduced several architectural concepts that remain fundamental:

• Electronic computation: Proved that electronic circuits could perform reliable calculations, replacing mechanical systems.
• Parallel processing: ENIAC could perform multiple operations simultaneously using its different accumulators.
• Modular design: The machine was composed of distinct functional units (accumulators, multipliers, etc.) that could operate independently.

Educational Impact

ENIAC played a crucial role in computer science education:

• The Moore School Lectures (1946) were the first formal courses in computer design, attended by many who would build subsequent computers.
• ENIAC’s development led to the creation of the first computer science curricula at universities.
• Many early computer science textbooks used ENIAC as a case study.

Military and Scientific Applications

After its initial ballistics work, ENIAC was used for:

• Hydrogen bomb research: Used by John von Neumann for thermonuclear calculations at Los Alamos.
• Weather prediction: First computer used for numerical weather prediction (1950).
• Wind tunnel design: Helped develop more efficient aircraft designs.
• Monte Carlo simulations: Pioneered this statistical technique with ENIAC.

Cultural Shift

ENIAC represented a cultural shift in how society viewed computation:

• Demonstrated that machines could perform intellectual work previously thought to require human intelligence.
• Challenged notions about what tasks could be automated.
• Created new categories of jobs (programmers, computer operators).
• Sparked public imagination about the potential of computers.

Frequently Asked Questions About ENIAC

Was ENIAC really the first computer?

ENIAC was the first general-purpose, electronic, digital computer. Other machines predated it:

• Atanasoff-Berry Computer (ABC, 1942): First electronic digital computer, but not general-purpose.
• Colossus (1943): British code-breaking computer, but specialized and kept secret until the 1970s.
• Harvard Mark I (1944): Electromechanical (relay-based), not fully electronic.
• Z3 (1941): Konrad Zuse’s electromechanical computer in Germany.

How did ENIAC compare to human computers?

Before ENIAC, “computers” were people (mostly women) who performed calculations manually:

ENIAC vs. Human Computers

Task	Human Computers	ENIAC	Speed Improvement
Artillery firing table (60-second trajectory)	40 hours	30 seconds	4,800× faster
Multiplication (10-digit numbers)	1 minute	0.0028 seconds	21,428× faster
Division (10-digit numbers)	5 minutes	0.024 seconds	12,500× faster
Error rate	~1 error per 1,000 operations	~1 error per 100,000 operations	100× more accurate

What happened to ENIAC after it was decommissioned?

After its decommissioning in 1955:

• Most of ENIAC was dismantled and discarded.
• Some components were saved for museums (Smithsonian, University of Pennsylvania, etc.).
• Several panels were used in classroom instruction at the Moore School.
• Some vacuum tubes and other components were kept as souvenirs by engineers.
• A reconstruction project began in 1995 to recreate parts of ENIAC for display.

Could ENIAC run modern software?

No, ENIAC couldn’t run modern software due to fundamental differences:

• No stored programs: Modern software requires programs to be stored in memory, which ENIAC lacked.
• Limited memory: ENIAC’s 20 accumulators couldn’t hold even the simplest modern programs.
• No operating system: All programming was done at the hardware level.
• Different architecture: ENIAC used decimal arithmetic, while modern computers use binary.
• No standard interfaces: No way to connect to modern storage or input/output devices.

How does ENIAC compare to a modern calculator?

Surprisingly, many modern pocket calculators are more capable than ENIAC in several ways:

ENIAC vs. Modern Scientific Calculator

Feature	ENIAC (1945)	Texas Instruments TI-36X Pro (2023)
Weight	30 tons	150 grams
Power consumption	150,000 watts	0.001 watts (solar-powered)
Addition time	200 microseconds	0.1 microseconds
Multiplication time	2.8 milliseconds	1 microsecond
Memory	200 digits (20 × 10-digit accumulators)	32 KB (400,000 digits)
Programmability	Physical rewiring (days)	Button presses (seconds)
Functions	Basic arithmetic, square roots	500+ scientific, statistical, and engineering functions
Cost (2023 equivalent)	$7.5 million	$20