Bitcoin block size could grow to 4 MB by 2026 – Report 

• Bitcoin network block size could expand to 4 MB by next year. 
• Mempool analysts believe the growth could be spurred by inscriptions. 

Bitcoin’s[BTC] scalability could be further enhanced by late 2026 amid projected block size growth to 4 MB.

According to the latest report by Mempool, a research firm focused on the Bitcoin ecosystem, stated that inscription-driven blockchain growth could explode in the next few years. 

Part of the report read, 

“If we see massive growth in the use of Bitcoin to store arbitrary data (resulting in consistent 4 MB blocks) the blockchain would reach 1TB by late 2026…We should expect a 1 TB blockchain after 2 – 4 years, and 2 TB in 7 – 9 years time.”

Source: Mempool

For perspective, the current block size is about 1.69 MB per block. This was initially capped at 1 MB before the SegWit (Segregated Witness) upgrade in 2017, which scaled the network significantly. 

Demand beyond 1 MB

Post-SegWit, there was a surge in inscription protocols that allowed extra arbitrary data (from texts to smart contracts) on the Bitcoin network.

Overall, the demand for block space exploded beyond the 1 MB limits, which was reported set by miners and the network’s default settings, noted Mempool. 

“The median block size increased until block 400,000 at which point the 1 MB consensus limit was reached, approximately 1.5 years before SegWit activation in block 481,824. Following SegWit’s introduction, block size gradually increased after an initial temporary decline”

Source: Mempool

The average block size growth surged between 1.11 MB and 1.69 MB, suggesting more transaction data per block. 

Mempool added that the above trend of massive adoption of inscription protocols could expand the block size to 4 MB. 

However, not every Bitcoin core dev is happy with the outlook.

According to one renowned dev, Luke Dash Jr, ordinals and inscriptions are ‘spam’ and ‘an attack’ on the Bitcoin network. Dash has always called for capping block size below 1 MB to limit this ‘attack’ vector.  

However, most of his X (formerly Twitter) users did not support his plan to cap Bitcoin block size at 300 KB in the second half of 2025. 

Source: X

Contrary to Bitcoin, Solana’s theoretical block size limit can reach 128 MB at much higher throughput. This means Solana is more scalable but less decentralized than BTC.

However, it remains to be seen how Bitcoin’s divergent views on block size increment will affect its adoption and scalability in the future.