Crypto Beginner

What is Unspent Transaction Output (UTXO)?


With the increasing popularity of crypto comes the need for better blockchain technology to improve its transaction process. One such improvement is the Unspent Transaction Output (UTXO). In this article, we will take a closer look at UTXO and its importance in the crypto landscape.

Introduction to UTXO

UTXO is a term used in blockchain technology for the leftover change from a transaction. It can be used as an input in future transactions.

The model is used in many blockchain-based cryptos, including Bitcoin and Litecoin.

Definition of UTXO

In technical terms, UTXO is the unspent output of a previous transaction. It can act as an input in a future transaction.
Understanding the functionality of UTXO

Now that we have a basic understanding of what UTXO is and why it is important, let’s take a closer look at how UTXO works.

How it works

UTXO works by breaking down transactions into smaller pieces. The small bits left over are then used as inputs for future transactions.

Transaction inputs and outputs

In a UTXO-based system, transactions are broken down into inputs and outputs. The input and output data of the transaction are recorded separately. The inputs are used to fund the transaction, and the outputs are the funds returned to the user. The former represents the funds used to fund the transaction, and the latter the funds that the user receives in the end. Any leftover funds are recorded as UTXOs and can be used as inputs for future transactions.

For example, a user wishes to send 1 BTC to another user. To do so, they must create a new transaction that specifies the UTXO(s) they wish to spend, as well as the recipient’s address. The transaction input would be the UTXO(s) they are spending, while the transaction output would be the new output(s) created, which would specify the amount of BTC being sent and the recipient’s address.

An example of UTXO in action

One common use for UTXO is in the Bitcoin network. In Bitcoin, each UTXO has a specific amount of BTC associated with it. Users can spend these UTXOs by creating new transactions. When a transaction is verified, the UTXOs are removed from the UTXO set, and a new transaction output is created.

The importance of UTXO in crypto

UTXO is a crucial concept in the world of crypto. It plays a critical role in the security, efficiency, and scalability of blockchain-based crypto. Here are some of the reasons why UTXO is important:

  • Efficiency: UTXOs help to simplify the transaction process by breaking down transactions into smaller pieces. This makes it easier to verify transactions and reduces the chances of errors.
  • Security: Since outputs from a previous transaction are recorded as such in this model, they cannot be double-spent. That makes such transactions more secure than traditional transactions, which rely on account balances.
  • Scalability: UTXOs help to improve the scalability of crypto by reducing the size of transactions. This allows for the processing of more transactions in a shorter time, leading to faster transaction times.

Advantages of UTXO

This technology represents a significant step forward for the blockchain industry, enabling more secure, efficient, and reliable transactions. To break that down, here are some of the key advantages.

Improved security for transactions

First, this mechanism allows for better privacy and security. That’s because each transaction can be traced back to its origin more easily, preventing double-spending and ensuring that transactions are irreversible.

Further, only the owner of the private key associated with the output can spend it. This ensures that the output is secure from any unauthorized access or tampering.

More efficiency for network

UTXO also brings significant efficiency gains to the blockchain network. Because each transaction output is recorded separately, this system simplifies the verification of the validity of transactions. By doing so, it reduces the time and resources required to validate transactions, helping maintain the integrity of the blockchain.

Increased scalability for crypto platforms

Another significant advantage is its ability to scale effectively. Crypto platforms that use this model scale better than those using other transaction models. This is because it allows for the efficient processing of a large number of transactions. It enables the blockchain to handle more transactions without slowing down or becoming congested.

As UTXO helps blockchain systems scale, it also makes it possible for developers to create new and innovative applications.

Challenges and limitations of UTXO

Despite its advantages, this model has several challenges and limitations that need to be addressed.

The complexity of UTXO systems and transaction costs

The model can lead to higher transaction fees because each UTXO must be individually signed.

It can also be challenging to create complex smart contracts or decentralized applications on the chain. This is where other blockchain models, like Ethereum’s account-based model, have an advantage.

Compatibility with different blockchain platforms

The unique features of such cryptos sometimes render them incompatible with other blockchain platforms. This can limit their usefulness in certain applications as developers find it more difficult to create applications that work seamlessly across multiple platforms.

UTXO-based blockchain size limits

Finally, these blockchains have size limits. Each UTXO requires a certain amount of space on the blockchain. As the number of transactions increases and the size of the blockchain grows, this can lead to a slowdown in transaction processing times and increasing costs.

Additionally, this model is not entirely private. Even though Bitcoin transactions are pseudonymous, UTXOs can be linked to a specific user, revealing their spending habits and balance.


UTXO is an important concept in blockchain-based cryptos because it ensures that each transaction output is recorded separately.

A summary of key points

The introduction of this technology makes it easier to verify the validity of transactions and allows for more secure transactions that cannot be double-spent. It also enables faster processing of transactions. That means lower transaction fees and improved network performance.

However, their complexity and scalability can present a challenge in the long run.

Future prospects in the crypto landscape

Despite its challenges, UTXO has a bright future in the crypto landscape. It continues to gain popularity among developers and users, and new solutions are being developed to address its limitations.

Therefore, as blockchain technology continues to evolve, it is likely to remain a critical component of blockchain architecture.


What is Unspent Transaction Output in UTXO model?

Unspent Transaction Output (UTXO) is a fundamental concept in the UTXO model, which is the transaction model used in blockchain systems like Bitcoin. In this model, the entire blockchain is not account-based, as in some other systems; instead, it’s based on a collection of individual transaction outputs.

What is Unspent Transaction Output in blockchain?

Unspent Transaction Output (UTXO) is a critical concept in the blockchain, especially in cryptocurrency systems like Bitcoin. It represents the cryptocurrency remaining in a user’s address after a transaction, and it plays a fundamental role in the security and verification of transactions in a blockchain network.

How is the Unspent Transaction Output or UTXO best described?

Unspent Transaction Output (UTXO) is best described as a fundamental concept in blockchain technology, particularly in cryptocurrencies like Bitcoin.

What is the UTXO error in the trust wallet?

UTXO errors are typically associated with Bitcoin and blockchain transactions.

Disclaimer: Crypto products and NFTs are unregulated and can be highly risky. There may be no regulatory recourse for any loss from such transactions. The information provided in this post is not to be considered investment/financial advice from CoinSwitch. Any action taken upon the information shall be at the user’s risk.

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