top of page

Quantum Computers vs Classical Computers: What's the Difference?

Quantum Computing

Quantum computing is a new type of computer that uses tiny particles called qubits to do calculations. Unlike regular computers that only use 0s and 1s to do math, quantum computers can use qubits that exist in many different states at the same time. This makes quantum computers really fast and powerful, especially for certain types of problems like simulating molecules or breaking codes.

To understand this Imagine you had to find a specific book in a library with a million books. A regular computer would have to check each book one by one to find it, but a quantum computer could check many books at the same time, making the search much faster and easier.

Classical Computing

Classical computing is the kind of computer we use every day, like phones, laptops, and tablets. These computers use simple "on" and "off" switches called transistors to do math and store information. They're great for doing things like browsing the web, playing games, or writing documents, but they can't do certain types of calculations as quickly as quantum computers can.

Think of a light switch in your room. When it's turned on, it sends electricity to the lightbulb and makes it turn on. When it's turned off, it stops the electricity and the light turns off. A computer works in a similar way, with transistors acting like tiny switches that can turn on or off to do calculations.

How Classical Computers Works

Classical computers operate using a system of binary code, which uses the digits 0 and 1 to represent information, and transistors to perform calculations. The transistors are arranged in circuits that can perform basic logical operations such as AND, OR, and NOT, and can be combined to perform more complex operations like addition, multiplication, and division. Additionally, circuits and logic gates can be programmed to follow instructions and perform different operations.

Limitations of Classical Computing: Classical computing is constrained by the amount of data it can store and the speed at which it can perform calculations. Although classical computers have improved significantly over the years, they still have difficulty handling large amounts of data and performing complex calculations quickly. This is partially due to the limitations of the binary code system, which can only represent two states (0 and 1). Consequently, classical computers may struggle with calculations that involve large amounts of data or complex systems.

How does quantum computing work compared to classical computing?

Quantum computers operate on the principles of quantum mechanics, using quantum bits or qubits, which can exist in multiple states simultaneously, known as superposition. Unlike classical computers that rely on binary digits to represent data, quantum computers use qubits to perform calculations exponentially faster.

The basic principles of quantum computing are:

  1. Superposition: A qubit can exist in multiple states simultaneously, allowing quantum computers to perform many calculations simultaneously, thereby speeding up the computing process exponentially.

  2. Entanglement: Qubits can become entangled with each other, meaning that the state of one qubit is dependent on the state of another. This allows quantum computers to perform complex calculations more efficiently than classical computers.

  3. Quantum gates: Quantum gates are used to manipulate qubits. They can perform operations such as rotation, phase shift, and entanglement, allowing quantum computers to perform a wide range of calculations.

  4. Measurement: Measuring qubits is a complex process that changes the state of the qubits, making it more difficult to obtain accurate results.

Advantages of quantum computing over classical computing
  1. Exponentially faster processing: Quantum computers can solve certain types of problems much faster than classical computers, making them an ideal solution for complex calculations.

  2. Increased data storage capacity: Quantum computers can store and process more data than classical computers, allowing them to handle complex calculations involving large amounts of data more efficiently.

Key difference between Quantum and Classical computing

Quantum computing and classical computing differ in their fundamental principles, which determine how they process and store information.The key differences between quantum computing and classical computing can be summarized as follows:

  1. Information storage: Classical computers use bits to store information, while quantum computers use qubits. Qubits can store much more information than classical bits, enabling quantum computers to handle much more complex calculations.

  2. Calculation speed: Quantum computers can perform certain types of calculations exponentially faster than classical computers. This is because qubits can exist in multiple states simultaneously, allowing quantum computers to perform many calculations at once.

  3. Error correction: Classical computers can use error correction algorithms to detect and correct errors in their calculations. Quantum computers also use error correction, but it is more complex due to the fragile nature of qubits.

  4. Limitations: Quantum computers are still in their early stages of development and are currently limited by the difficulty of building reliable qubits and error correction systems. In contrast, classical computers are well-established and have reached a plateau in their processing power.

Challenges and Limitations of quantum Computer

While quantum computing has the potential to revolutionize the way we process and store information, there are still several challenges and limitations that need to be overcome before it becomes a practical technology.

  1. Building reliable qubits: Qubits are the basic building blocks of quantum computers, and they are extremely fragile. They are susceptible to environmental noise, which can cause errors in calculations. Building qubits that are stable enough to perform reliable computations is a major technical challenge.

  2. Error correction: Quantum computers are prone to errors due to the nature of qubits. Unlike classical bits, qubits can exist in multiple states simultaneously, making them much more susceptible to environmental noise. Developing error correction techniques that can detect and correct these errors is a significant challenge.

  3. Scaling up: Quantum computers need to be scaled up to perform useful computations. This involves increasing the number of qubits and developing new algorithms that can take advantage of the increased computational power. However, scaling up quantum computers is challenging because it requires maintaining the coherence of the qubits as they interact with each other.

  4. Access and usability: Quantum computers are currently only available to a limited number of researchers and companies. Making quantum computing more accessible and user-friendly is an important challenge that needs to be addressed.

For example, companies like IBM and Google have developed cloud-based quantum computing platforms that allow researchers to run quantum algorithms using remote quantum computers. However, the complexity of quantum computing algorithms and the limited availability of quantum hardware can still make it difficult for researchers to use quantum computing for their work.


Quantum computing represents a major breakthrough in the way we process and store information. Classical computing operates on binary code, whereas quantum computing is based on the principles of superposition and entanglement. This allows quantum computing to exponentially increase processing power and data storage capacity, making it a promising technology for a wide range of industries.

The potential impact of quantum computing on the future of technology is significant, with possibilities for improved drug discovery, optimization problem solving, and enhanced data encryption. However, quantum computing still faces challenges, such as building reliable qubits and developing error correction techniques, before it becomes a practical technology.

Furthermore, the connection between quantum computing and the brain and universe research is an exciting area of exploration. Quantum computing has the potential to revolutionize our understanding of these complex systems, and it is crucial that we continue to research and develop this technology.

This content is created with the help of


bottom of page