blockspace.wiki
The witness discount
A witness byte weighs a quarter of a base byte, so it costs a quarter as much at the same fee rate. The short version, with links to the full page.
The witness discount is the rule, from segwit, that a byte in a transaction's witness counts 1 weight unit and every other byte counts 4. The full page, with the measurements and the theory, is the witness discount. This is the short version.
In one line #
block.space's data-types reference: "witness bytes are real bytes on disk and on the wire, but count 1/4 toward the 4,000,000 WU consensus block limit." Because fees are priced in vbytes, a witness byte also costs a quarter as much as a base byte at the same fee rate.
What it changes #
Where data goes depends on the price. The reference's channel comparison, per data byte at f sat/vB:
- a Taproot witness envelope: 1 WU, f/4 sats;
- OP_RETURN: 4 WU, f sats.
That is why, in the reference's words, every high-volume protocol (ordinals, BRC-20, Alkanes WASM, Counterparty v11) "converged on" the witness envelope, while OP_RETURN keeps small structured messages such as runestones.
How much each protocol takes #
Bytes divided by vbytes shows how much of the discount a protocol takes. In the July 2026 measurement run on block.space it was 3.374 for inscriptions, 1.008 for stamps, 1.0000 for runestones and 1.0142 for Omni. BTI keeps both raw bytes and vbytes on every row so this ratio stays visible.
Two readings #
The mechanism is a fact about weight. What it means is argued. Blockspace Value Theory proposes that the discount is "a price subsidy, not a capacity increase": witness bytes are downloaded, validated and stored like any others, so they use the same scarce resource at a quarter of the price. BVT is a living document and an untested thesis. BTI's books follow its measuring rule, raw bytes with no weight discounting, without taking a view on value.
Related #
Sources #
Updated 2026-10-20 · This page as Markdown