Blockchain Network Congestion: A Complete Guide

By Olayiwola Dolapo
16 Min Read

The introduction of “digital currency,” “cryptography,” and “blockchain” represents some of the latest innovations transforming digital age technology. This breakthrough comes with terminology and mechanisms that offer optimum benefits when properly understood. One frequently used term is “blockchain congestion” or “network congestion.”

Blockchain network congestion occurs when the number of transactions to be processed exceeds the inherent capacity, resulting in extended processing times and a backlog of transactions. In practical terms, blockchain congestion often arises during cryptocurrency bull runs, coinciding with increased buying and selling, leading to a surge in transactions. This results in processing delays, a sluggish network, and a rise in gas fees.

The volume of transactions and interactions within the blockchain network exceeding its capacity can cause congestion. Several factors contribute to blockchain congestion, including market volatility, intrinsic network capacity (blocksize), decentralized applications (dApps), and DeFi protocols.

For a comprehensive guide on decentralized applications (dApps), check out this article by DroomDroom.

Increased crypto adoption and events like initial coin offerings (ICOs) elevate the blockchain congestion rate. Consequently, transactions become more expensive, and less efficient, and adversely impact the overall user experience.

Explore what “blockchain network congestion” is and understand its implications on blockchain technology sustainability and scalability in this comprehensive guide to “network congestion” and its potential solutions.

Understanding Blockchain Technology

A blockchain is a unique form of database, also known as a decentralized digital ledger, maintained by numerous computers globally. Blockchain data is structured into blocks, chronologically ordered, and secured by cryptography. Blocks are computer files containing transaction data, a timestamp, and a cryptographic hash—referencing the prior block arranged sequentially to create an endless chain known as a blockchain.

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How Does Blockchain Work?

Blockchain records transactions in a tamper-proof manner, typically logged by a distributed network of computers known as nodes. Nodes, and special computers, validate and record network transactions. When a user initiates a transaction, it’s broadcast to the network, awaiting verification by nodes. Each node authenticates the transaction through a consensus mechanism by verifying the digital signature. A verified transaction is added to a block of other verified transactions, chained together by cryptographic means to form a blockchain. This verification process is governed by a consensus mechanism.

Consensus Mechanism

Consensus mechanisms are algorithms that ensure all users or computers coordinate in a distributed setting. The most popular mechanisms include Proof of Work (PoW) and Proof of Stake (PoS).

Proof of Work (PoW)

This consensus mechanism, originally used by Bitcoin, is employed by many blockchains to verify transactions and maintain network integrity. In PoW, miners compete to solve a complex mathematical algorithm problem during the transaction verification process, adding a new block to the blockchain. The first miner to solve this problem receives a cryptocurrency reward. However, this process demands a significant amount of energy and computational power.

Proof of Stake (PoS)

PoS utilizes a staking/locking mechanism to add a new block to the blockchain. Validators validate transactions and add new blocks by staking a significant amount of cryptocurrency as collateral. Validators receive transaction fees as an incentive for staking and contributing to network development.

While PoW and PoS are common consensus algorithms, others improve upon their qualities, and hybrids combine both systems. For instance, Delegated Proof of Stake (DPoS) is akin to PoS, but instead of all validators being eligible to create new blocks, token holders elect a smaller set of delegates to do so on their behalf.

Mechanism of Network Transaction

Blockchain congestion can be well explained by examining the network processing ability, which includes mempools, candidate blocks, finality, and the longest chain principle.


This serves as a short memory pool, acting as a waiting area for unconfirmed transactions. Once a transaction is confirmed, it is removed from the mempool and proceeds to the next processing phase.

Candidate blocks

These are also known as “proposed blocks,” and contain transactions undergoing verification by miners or validators to be included in the blockchain. The verification mechanisms may include Proof of Work (PoW) used by the Bitcoin Blockchain or Proof of Stake (PoS) used by the Ethereum blockchain, among others.


This signifies the point when a transaction has been confirmed, recorded on the blockchain, and is immutable—unable to be changed, removed, or altered.

The Longest Chain Principle

This involves rules validating blocks with the longest chain resulting from significant computational work. This principle distinguishes them from shorter chain blocks, termed orphan or stale blocks.

Understanding Blockchain Network Congestion

Blockchain congestion in blockchain occurs when the number of transactions surpasses the processing capacity of the network. The blockchain’s operation is confined to processing and validating transactions in fixed-size blocks, each with a predetermined processing speed. Consequently, the network can only handle a limited number of transactions within a given timeframe. When the processing demand exceeds its inherent capacity, network congestion ensues, causing a domino effect on the entire system.

What Causes Blockchain Network Congestion? 

A blockchain network may encounter congestion due to various factors:

Increased Demand

The growing global demand for blockchain technology, seen notably in networks like Bitcoin and Ethereum, leads to a surge in transactions. As more users engage with the blockchain, the number of unconfirmed transactions in the mempool surpasses a single block’s inherent capacity, causing concern for blockchains with limitations in block size and processing time.

Small Block Size

Blockchains typically have a predefined block size, determining the block’s capacity and maximum data limit. This size dictates the number of transactions a block can accommodate, directly contributing to network congestion.

Slow block times

Blockchain network congestion can arise from slow block times, where block time is the average duration a network takes to add a new block of transactions to the blockchain. For instance, Bitcoin typically adds a new block approximately every 10 minutes, while Ethereum achieves this in less than 15 seconds. When transaction demands exceed the pace of block time, a backlog of unconfirmed transactions accumulates in the mempool.

An example of blockchain congestion occurred on the Arbitrum network:

 Effects of Blockchain Network Congestion 

Blockchain network congestion presents challenges to network operation and usability, notably hindering seamless transactions.

Increase in Transaction Fees

One issue is the surge in transaction fees. Blockchain network congestion leads to higher transaction or gas fees, as miners prioritize transactions with greater fees for increased incentives. This fee inflation significantly raises the overall cost of utilizing the blockchain, particularly impacting smaller transactions.

Delayed Confirmation Times

Another problem is the delayed confirmation times. Congestion extends the backlog, increasing the average time needed to confirm a transaction. This prolonged waiting period for transaction finality introduces uncertainty and inconvenience, causing frustration and financial implications for users in trading environments.

Poor user experience

Suboptimal user experience is a key concern, as high transaction fees and delayed confirmations significantly impede the potential adoption and scalability of blockchain. This negatively impacts the network’s reputation, prompting users to migrate to more efficient platforms.

Market Volatility

Moreover, congestion contributes to market volatility by introducing uncertainty. Delayed transactions cause substantial price changes before execution, resulting in either losses or profits for users. Unusual delays also evoke emotional responses, further contributing to market volatility. Additional consequences include the risk of network centralization and security risks within the blockchain.

General Solutions to Blockchain Network Congestion

Blockchain congestion can be addressed through various methods, approaches, and technologies, each with distinct advantages and disadvantages.

Increase Block Size

The block size denotes the maximum data that can be included in a single block. Enlarging the block size facilitates the processing of more transaction data per block, diminishing the risk of blockchain congestion. However, larger blocks necessitate a significant time to propagate through the network, potentially leading to temporary forks.

Decrease Block Time

Block time is the allocated duration for creating a new block. Reducing block time enables more blocks to be generated within a set timeframe. Nevertheless, a shorter block time increases the occurrence of short or orphaned blocks, potentially compromising the system’s security.

Layer 2 Solutions

Layer 2 solutions, often known as off-chain solutions, operate outside the main blockchain and reduce congestion on the main chain by creating additional space. These solutions are constructed atop the main blockchain (base layer) and handle transactions off the main chain while recording the finality state on-chain. An example of such a solution is Bitcoin’s Lightning Network, enabling payment transactions between users without main chain processing. Ethereum’s Plasma serves as another framework, enabling the creation of a secondary blockchain running parallel to the main one. These solutions significantly enhance the scalability of the blockchain network.

You can also read this complete guide by DroomDroom to learn more about Polygon a layer 2 blockchain solution.


This is a technical method that involves the splitting of the blockchain into smaller shards, each capable of processing transactions and executing smart contracts. It significantly increases network capacity, complexity, and security.

History of Blockchain Network Congestion

Popular blockchain networks like Bitcoin and Ethereum have encountered periods of blockchain congestion, impacting transaction fees and users’ experiences.

Bitcoin Network Congestion

Bitcoin witnessed a substantial increase in price and blockchain congestion in late 2017 and early 2018. The rising adoption of Bitcoin, driven by its popularity, attracted an overwhelming number of transactions, leading to a substantial backlog of unverified transactions. Consequently, delays and high transaction fees ensued.

In mid-2023, the Bitcoin network experienced a breakthrough with the creation of BRC-20 tokens through the Ordinals protocol. This surge in transaction activities resulted in a significant number of unconfirmed transactions in the mempool, leading to an approximately 300% increase in transaction fees during this period.

Ethereum Network Congestion

Ethereum typically encounters congestion issues, albeit to a lesser extent than Bitcoin. However, in 2017, during the surge in Initial Coin Offerings (ICOs), numerous companies utilized the Ethereum network to launch their tokens, causing significant congestion. It’s important to note that any blockchain network can experience congestion, but the attention garnered by Bitcoin and Ethereum in the industry has been notable.

For additional insights into Initial Coin Offerings, you can explore a comprehensive guide provided by DroomDroom that covers everything you need to know.

Future Perspective on Blockchain Network Congestion  

The widespread adoption of blockchain technology globally is on the horizon, and addressing blockchain congestion is crucial for ensuring an optimal user experience. Despite the ongoing challenge of congestion as we envision the future of blockchain technology, the community remains dedicated to countering this threat through innovative research, holding the potential to alleviate these challenges.

While blockchain blockchain congestion presents significant hurdles, the community is actively working on solutions to mitigate these issues. Consequently, research focused on enhancing blockchain scalability takes a prominent position in the industry.

Moreover, the advent of new blockchain networks such as Polkadot, Cosmos, and Cardo is notable for their well-structured approach, incorporating scalability, adaptability, and interoperability. These networks introduce diverse consensus algorithms and cross-chain communication, offering a promising path toward a less congested blockchain future and a reduced risk of blockchain congestion.

Frequently Asked Questions (FAQs)

Which Blockchains Are Susceptible to Congestion?

Most popular blockchains, such as Bitcoin and Ethereum, can experience congestion during periods of high demand. However, the severity and frequency vary between different blockchain networks.

Which Blockchains Are Susceptible to Congestion?

Congestion occurs when more transactions are waiting to be processed than the network can handle within a reasonable time. Factors contributing to congestion include increased transaction volume, limited block size, and network scalability issues.

How Does Congestion Affect Transaction Confirmation Times?

Congestion typically results in longer confirmation times for transactions. As the network struggles to process a large number of transactions, users may experience delays in their transactions being included in a block.

Are There Any Solutions to Blockchain Congestion?

Blockchain developers are actively working on solutions to address congestion. Some approaches include increasing block sizes, implementing off-chain scaling solutions, and transitioning to new consensus mechanisms.

What Is the Role of Transaction Fees in Managing Congestion?

Transaction fees act as an incentive for miners to include transactions in a block. During congestion, users who offer higher fees have a better chance of having their transactions processed promptly.

What Is the Impact of Congestion on Transaction Fees?

During periods of congestion, transaction fees often increase as users compete to have their transactions processed quickly. Higher fees can incentivize miners to prioritize certain transactions.

After losing his DOGE tokens due to a limited understanding of blockchain technology, Dolapo made a pledge to explore its vast potential. Now, as a dedicated writer, he sheds light on the intricacies of this innovative technology for others. Dolapo distinguishes himself with his expertise in marketing.