$NAT · Security Budget Tools

How much does Bitcoin pay for its own security?
There is a number, and experts already priced it.

BSI — Bitcoin Security Intensity: what Bitcoin is paying for its own security right now, at an annual rate, as a share of market cap. Five figures have been published — targets, a comparator, a 2020 measurement, and our own. Each is labelled for what it is, and none is scored. Bitcoin is falling past all of them on a schedule.

Every published figure, in order — and where Bitcoin sits among them.

StatusFIGURES VERIFIED

Checked31 Aug 2026

Next halving~Apr 2028

Not a price feed. Price cancels from both sides of the ratio, so this figure does not move with the market. Fees are the only variable part — 0.006pp of the 0.82%.

What the 0.82% is made of

Block subsidyhalves every ~4 years0.819%

Transaction feesdoes not halve0.006%

Bitcoin Security Intensity0.825%

The scale — and what it would take to get back inside it

Every published benchmark is a zone; the lit one is where Bitcoin currently stands. Move the halving year and the fee multiple — the needle moves with them. Price is deliberately absent: it cancels out of the ratio.

today 0.82%

0.82%

below every floor<0.5%

inside Alden0.5–1%

healthy · NAT target1–1.5%

above the published range>1.5%

← “a different protocol”

0.5% Alden floor

0.7% gold

1% NAT paper

1.5% ceiling

2% Hasu

Where on the schedule

Fees, as a multiple of today

1×today’s fee revenue

$NAT — the second subsidy

$NAT market cap, as a share of Bitcoin’s 2.00%

Who published what

Every row is read against the scenario you set above: the marker is Bitcoin’s current position on that source’s own scale. Distance is the fee multiple that would lift Bitcoin to that source’s floor; click it and the slider goes there. Source opens the verbatim quote — and, under it, the two things that would close the gap to that specific source: fees, or $NAT. These are not our numbers; the bridge to $NAT is ours alone.

6 on BSI · 2 on attack cost · every row states its source and whether it is verified

WhoPublished level (0–2.2% of cap)Levelvs. scenarioDistanceSource

Lyn Alden2021·of market cap

0.5–1.5%

“something more like 0.5% to 1.5% of market capitalization spent on security would probably be appropriate.”

Read the source ↗On The Wall ▶ The videos

Hasumeasured 2020·not a target

“One could say Bitcoin’s security budget is 2% of its network value.” — a measurement of 2020, not a level he prescribed. It is on this page as a reading Bitcoin has already fallen below, never as a bar to clear.

Hear it at 3:04 ↗On The Wall

James McAvity18 Oct 2023·The Mining Pod

1–1.5%

“The metric that I like to look at is what is mining revenue versus the total market cap of Bitcoin. And right now it’s around one and a half percent. You wanted to stay in a healthy range there.” — his floor is the row below.

▶ Watch him say it

The NAT paperp.3 / p.18·OUR OWN target

>1%

“Elevate BSI above 1%” — the level the proposal is engineered to reach. It sits inside every band above.

Read the paper ↗The explorable →

GoldSam Wouters 2023·comparator, not a floor

~0.7%

“If you do take that approach of the 0.7 percent — which is, from what I could tell, sort of what people are spending to secure their gold every year — if you take that for Bitcoin, then you get to a security budget currently of about 2.2 billion.” The closest thing to a floor anyone has. One more halving puts Bitcoin under it.

Hear it at 31:20 ↗▶ The videos

“A different protocol”McAvity·floor

0.1–0.2%

“If that drops down to say 20 basis points, 10 basis points, maybe even lower … It’s just a different system. It’s a different protocol.” — the schedule reaches it in three more halvings.

▶ Watch him say it

Two Ethereum critics, counting what an attack costs rather than what Bitcoin pays, put the floor at 0.1% — inside the 0.1–0.2% a Bitcoin miner called “a different protocol”. different basis ▾

Grant Hummer2025·Etherealize co-founder

not on this axis — see below

0.1%

the floorattack “virtually certain”

“Respectfully, BTC is completely screwed because of its security budget. It would only cost $8B to 51% attack BTC today. When this gets down to $2B (AKA, BTC’s security market cap becomes 0.1% of its asset market cap), a 51% attack is virtually certain to happen. This will become blindingly obvious over the next decade. ETH is the only truly decentralized crypto-asset that can become the internet’s SoV Schelling point.”

Justin Drake2025·Ethereum Foundation

not on this axis — see below

$10B

May 2025“a rich nation state”

A 51% attack on Bitcoin would be “much cheaper” than on Ethereum, costing “on the order of $10 billion”. “A rich nation state can probably pull it off.”

Their ruler — one-off cost to attack ÷ market cap axis 0 → 0.6% · a capital stock, not an annual flow — never summed with BSI

0.1%Hummer · “virtually certain” ~0.4%$8B · May 2025 ~0.5%$10B · May 2025

0.1% and the $8B / $10B attack costs are quoted. The ~0.4% and ~0.5% positions are derived — their dollar figures over the ~$2T market cap their own arguments assume. We show the arithmetic rather than quoting a ratio neither man stated.

Why they are here at all. Opposite incentives, different rulers, the same floor. Neither is a friendly witness — Hummer’s same post argues ETH should be the store-of-value Schelling point instead, and we quote that sentence rather than cutting it. That is the point: the floor is agreed by people who agree on nothing else.