Block size limit controversy – Bitcoin Wiki

Block size limit controversy

Blocks are limited to 1MB in size. Miners can mine blocks up to the 1MB immobilized limit, but any block larger than 1MB is invalid. This limit cannot be modified without a hard fork. To prevent Bitcoin from temporarily or permanently splitting into separate payment networks (“altcoins”), hard forks require adoption by almost all economically active utter knots.


Arguments in favor of enlargening the blocksize

  • More transactions per 2nd
  • Off-chain solutions are not yet ready to take off the geyser from the main blockchain.


  • Enlargened blocksize will leave space for extensions like Mastercoin, Counterparty, etc.
    • Neutral: Bitcoin competitors will have lower fees
    • Negative: Bitcoin total knots are compelled to use more resources that don’t support Bitcoin
  • Puny blocks eventually will require higher fees for prompt confirmations.
    • Positive: It will no longer be cheap to spam transactions such as Satoshi Dice bets
    • Positive: Fees will not be zero. This is eventually a necessity in order to incentivize miners and secure the mining ecosystem
    • Negative: Bitcoin may look unattractive to fresh users with high fees
    • Negative: High fees may stop or switch sides global adoption, investment, development, support and centralization [clarification needed]
    • Negative: Bitcoin users pay higher fees
  • A low blocksize limit encourages higher transactions fees to incentivize miners (“let a fee market develop”).
    • A fee market naturally develops due to miner latency regardless [1]
      • The relay network can be optimized so that miners don’t have a stale rate enlargening with latency. This should cause the fee market to once again require a block size limit to exist.

Arguments in opposition to enhancing the blocksize

  • A hard fork requires waiting for sufficient consensus.
  • Risk of catastrophic consensus failure [Two][clarification needed]
  • An emergency hard fork that can achieve consensus can be deployed on a brief time period if needed. [Trio]
  • Orphan rate amplification, more reorgs and double-spends due to slower propagation speeds.
  • European/American pools at more of a disadvantage compared to the Chinese pools [why?]
  • “Congestion” concerns can be solved with mempool improvements including transaction eviction.
  • No amount of max block size would support all the world’s future transactions on the main blockchain (various types of off-chain transactions are the only long-term solution)
  • Rapid block propagation is either not clearly viable, or (eg, IBLT) creates centralised controls.

Harm to decentralization

  • Larger blocks make utter knots more expensive to operate.
  • Therefore, larger blocks lead to less hashers running total knots, which leads to centralized entities having more power, which makes Bitcoin require more trust, which weakens Bitcoins value proposition.
  • Bitcoin is only useful if it is decentralized because centralization requires trust. Bitcoins value proposition is trustlessness.
  • The larger the hash-rate a single miner controls, the more centralized Bitcoin becomes and the more trust using Bitcoin requires.
  • Running your own utter knot while mining rather than providing another entity the right to your hash-power decreases the hash-rate of large miners. Those who have hash-power are able to control their own hash power if and only if they run a total knot.
  • Less individuals who control hash-power will run total knots if running one becomes more expensive [Four] .


BIP 100

Switch block size limit based on miner votes, but don’t leave the range (1MB, 32MB) without a softfork or hardfork respectively.

BIP 101

Increase to eight MB after both January 11, two thousand sixteen has passed and 75% of miners are supporting. Dual the limit every two years with the size enlargening linearly within those two year intervals.

BIP 102

Increase to two MB on November 11, 2015.

BIP 103

Increase by 17.7% annually until 2063.

BIP 109

Hard Fork to 2MB in 2016. Dynamic max_block_size in 2017.

Entities positions

Positions below are based on a suggested immovable block size increase to 20MiB. Positions against these larger blocks do not necessarily imply that they are against an increase in general, and may instead support a smaller and/or gradual increase.

“At this time, I oppose enhancing the block size limit as per Gavin’s proposal” – Nadav Ivgi (founder) [9]

“This *is* urgent and needs to be treated right now, and I believe Gavin

has the best treatment to this.” – CEO Alan Reiner [15]

“Agreed (but optimistic this will be the last and only time block size needs to increase)” – CEO Stephen Pair [Legal]

“I’m strongly in favor of the block size cap increase to 20MB.” – CEO Henry Brade [21]

“And I’m in favor of releasing a version with this switch even with opposition.” – CEO Henry Brade [22]

“It is time to increase the block size. Agree with @gavinandresen” – CEO Peter Smith [23]

“Scaling #bitcoin is a big deal. Increase the block size.” – Nic Cary [24]

“We’d love to see BIP101 with 4mb begin, alternatively BIP100 with something to deal with the 21% attack could be good too.” [25]

“[. ] in support of the Gavin’s 20Mb block proposal.” – CEO Aaron Voisine [26]

“Needs to happen, but needs future expansion built in at a reasonable rate.” – Eleuthria [27]

“Why we should increase the block size” – CEO Brian Armstrong [30]

“We see Bitcoin XT as the best solution for ensuring the future scalability of the Bitcoin network.” – CTO Hamed Sattari [32]

“I strongly urge that we comeback to the existing collaborative constructive review process that has been used for the last four years which is a consensus by design to prevent one rogue person from inserting a backdoor, or lobbying for a favoured switch on behalf of a special interest group, or working for bad actor” – Dr. Adam Back [34]

“#Kryptoradio dev @zouppen supports 20MB block size in #bitcoin.” – Joel Lehtonen [35]

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