Blockspace

Blockspace

What blockspace is: the bytes Bitcoin's blocks hold, as BTI counts them, and what Blockspace Value Theory proposes about them.

Blockspace is the space in Bitcoin's blocks: the bytes of every transaction a block holds. This page keeps two things apart. The first half is what is measured: how many bytes the chain holds and how the Blockspace Token Indexer counts them. The second half is what Blockspace Value Theory proposes about those bytes. That half is theory, and it is attributed to BVT.

What is counted #

BTI "walks every Bitcoin transaction, from the genesis block forward, and counts every byte exactly". For each transaction and each block it records four numbers: raw size, virtual size, weight and fee. "Nothing is sampled and nothing is estimated": the per-transaction counts reconcile against each block's exact serialized size. This first stage is the byte census.

The census reads, as of block 972,315, 2026-10-20 11:58:41 UTC:

972,316 blocks;
1,464,214,951 transactions;
777.06 GB of raw bytes;
567.71 GB in virtual bytes (vbytes).

Raw bytes and vbytes are two different measures of the same data. The fee market charges by vbytes, and witness data is discounted in that measure. See weight units and vbytes and the witness discount. BTI keeps every entry in both.

How it is divided #

BTI sorts every byte of every block into one of four categories, which together add up to the block's exact size:

claimed bytes back a living token;
carriage bytes moved a token without being bought for it;
burned bytes backed tokens that were provably destroyed;
unclaimed bytes back nothing; they are "the majority of every block".

No byte is in two categories. The block.space docs call this partition "the Meter's trust anchor". Claimed bytes are written into the three books. The broadest of them, Book A (the inclusive book), attributes 133.75 GB to tokens, which is 17.21 % of the 777.06 GB it covers (as of block 972,299, 2026-10-20 09:30:48 UTC). Carriage is explained on carriage and the free-ride index.

How the use of blockspace changed #

The July 2026 measurement run on block.space measured data payload as a share of all block bytes at a few heights:

height	share
450,000	0.0 %
600,000	9.2 %
788,000	13.4 %
833,000	45.4 %
850,000	31.9 %

The docs read the fall after the peak as "runes replacing inscription bodies with 20-byte runestones". The same run measured the ratio of bytes to vbytes per protocol: 3.374 for inscriptions, 1.008 for stamps and 1.0000 for runestones. A higher ratio means a protocol pays for a smaller share of the bytes it uses.

What BVT proposes blockspace is #

BVT opens with the claim that the word "does not survive inspection". It argues that blockspace "has no location, no duration, and no existence independent of the moment a block is constructed", and puts it in bold: "blockspace exists only during block construction." Its formulation:

Blockspace is a socially constructed commodity built on top of a protocol-enforced constraint.

BVT treats both halves as necessary. The constraint is real: blocks have capacity limits that producers must respect. The commodity is "a useful fiction" that lets markets form around the decision of what goes into a block.

BVT divides the life of blockspace into three phases:

Phase	What is traded
Pre-block	Bids for inclusion, derivatives
Construction	The producer's allocation decision
Post-block	Blockspace tokens, "receipts of consumption"

BVT says nearly all commentary concerns the first phase, and calls itself "a theory of phase three".

What BVT proposes limits it #

BVT does its arithmetic at a 4,000,000 weight-unit limit. A maximally witness-heavy block then approaches 4 MB, which gives a ceiling of about 210 GB a year. BVT version 3.0 says this is "a ceiling" and not a schedule; actual use "follows the fee market". It places the real limit elsewhere, in the decentralization constraint: the supply is "limited to the largest the blockchain could grow while still keeping verification decentralized." On that reading, BVT says, blockspace value is "the value of keeping verification decentralized."

BVT also proposes that raw bytes, not vbytes, are the honest measure, because every node downloads, validates and propagates witness bytes in full. BTI's design takes this as a requirement: "raw bytes are the measure; vbytes are an observable", so both are carried everywhere.

Tokens and blockspace #

In BVT's terms, a blockspace token is any asset "whose existence required the permanent consumption of Bitcoin block capacity". It is a receipt, not a claim on capacity. The Shared Claim Axiom adds the accounting: how the bytes are shared when several tokens claim the same transaction, and what happens to the bytes no token claims. The axiom notes that "most consumed blockspace has no claim on it at all", which matches the unclaimed majority the books measure.

A limit on measurement #

BVT records a limit on how any byte census of this kind is built. Protocols are found by their markers, and "it fails silently against any protocol that obfuscates its marker." A byte scan on 2026-08-04 found zero SRC-721 occurrences across blocks 820,600 to 823,200 while Counterparty's own API showed SRC-721 mints live. So BVT says a figure for unattributed bytes should be read as "not attributable by marker detection", which "is a claim about the instrument, not about the chain."

Sources #

Live figures: books as of block 972,299, 2026-10-20 09:30:48 UTC; census as of block 972,315, 2026-10-20 11:58:41 UTC. Refreshed hourly.