Bitcoin security budget · the fee question

Can transaction fees alone replace Bitcoin's block subsidy?

Fees would need to reach about 18% of miner revenue and stay there, roughly 29× today’s 0.64%. Bitcoin’s longest run above 20% is 40 days, ending 2018-01-31. Above 30%: never.

What the requirement is

Today’s gap to a 1% target is $2.77B a year, or $52.7K per block. Fees currently contribute about $1.8K per block on a trailing-year basis. Closing the gap on fees alone means multiplying that by roughly 29× and holding it, not reaching it once.

The historical record

Threshold, fees as a share of miner revenueLongest sustained runEnded
Above 10%100 days2018-02-15
Above 20%40 days2018-01-31
Above 30%0 days
Above 50%0 days

The best 30-day window in Bitcoin’s history is January 2018 at 26.2%, which is still well under the 18% required. See the full fee history.

Why peaks do not settle it

Fees have spiked far higher than 18% — the single highest day on record is 2024-04-20 at 75.2% of miner revenue. But a spike is a congestion event, and congestion ends. The security budget is an ongoing cost, so what matters is the sustained level, and the sustained record is the table above.

The scale problem underneath

A fee market 29× today’s size means users paying 29× more, in total, for the same block space. That is either far more transactions at today’s prices, which the block size does not allow, or today’s transaction count at far higher prices, which pushes ordinary use off-chain. Both are real possibilities. Neither is a small change to how Bitcoin is used.

Sources

Figures as of 2026-09-07 · generated 2026-09-08 from the same data file that feeds the FAQ’s sizing section. How these figures are computed · about & corrections. Machine-readable: data.json, history.csv. Dated permalink: /security-budget/2026-09-07/.