Block size is still limited to 1MB. As I understood, transaction size is no longer limited. So can I be sure that my transaction with 29000 outputs and reliable fee will be included into block? Or what is the max transaction size?

  • Yes, but the question and both answers are not relevant now
    – Lizzy Bug
    Commented Mar 5, 2019 at 13:42
  • Related: Block 364292 is basically one massive transaction: blockstream.info/block/…
    – chytrik
    Commented Mar 5, 2019 at 21:16

1 Answer 1


Can I send almost 1MB transaction?

To be able to send a transaction that a miner will accept, that transaction has to be a standard transaction. As defined in policy.h

/** The maximum weight for transactions we're willing to relay/mine */
static const unsigned int MAX_STANDARD_TX_WEIGHT = 400000;

For non-Segwit transactions, the limit is 400,000 KB / 4 = 100,000 B = 100 kB.

Therefore, if you have a Pre-Segwit transaction larger than 100 kB but smaller than the block s̶i̶z̶e weight limit, you should contact a miner, and they'll be able to add your transaction to their block manually, if it's profitable for them.

  • 1
    So 100kB limit still persists, I was confused by the comment to bitcoin.stackexchange.com/a/35882/92719 . Thanks a lot
    – Lizzy Bug
    Commented Mar 5, 2019 at 14:33
  • You're welcome. If you have any other questions, I'm happy to help.
    – MCCCS
    Commented Mar 5, 2019 at 14:36

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