Bitcoin Block Size
Latest full day
1.54 MB
-2.68%vs 30-day average
Average of every block mined on Oct 14, 2026 (UTC)
The average Bitcoin block was 1.54 MB on Oct 14, 2026, filling 97.6% of the 4 million weight-unit limit. Over the last 30 days blocks averaged 1.58 MB.
- All-time high
- 2.52 MB
- Feb 12, 2023
- 30-day average
- 1.58 MB
- Weight limit used
- 97.6%
- Average block, latest day
- Witness data
- 48.8%
- Share of those bytes
What it means
How many bytes the average block carried each day. The cap is on weight, not bytes.
Since SegWit, Bitcoin caps a block at 4 million weight units instead of 1,000,000 bytes. A byte of witness data counts as 1 unit and every other byte as 4, so a full block can be anywhere from 1 MB to just under 4 MB, depending on its mix. On Oct 14, 2026, about 49% of the average block's bytes were witness data, which is how 1.54 MB fit inside the limit. The daily average first reached 1 MB on Oct 2, 2017.
How it’s averaged
Every block, bucketed by UTC day and averaged. No smoothing.
Our node records each block's size in bytes. The chart groups blocks by UTC day with date_trunc('day', timestamp) and plots the plain average, with no interpolation and no moving average. The day in progress is left out until it closes, so the latest point is always a full day. Sizes are decimal: 1 MB is 1,000,000 bytes.
Why there is a limit
Bigger blocks travel slower and cost every node more to check.
A larger block takes longer to reach every miner, which raises the odds that a competing block wins the race and the slower one goes stale. That risk falls hardest on miners with weaker connections. Block size also sets what it costs to run a node: every byte is downloaded, checked and stored by everyone who verifies the chain.