Solana raises block limit to 100M CUs; per-account cap unchanged

Solana increased its per-block compute limit from 60 million to 100 million compute units (CUs) on July 29. The change is recorded on the on-chain feature account as SIMD-0286, active at slot 435,888,000 at the start of epoch 1009, and raises the total computation a block leader may include before marking a block full.

Compute units quantify the computation transactions perform. The block ceiling caps the sum of that work per block. Solana Foundation materials present the mathematical increase as 66% and note that 11.2% of blocks produced between July 22, 2025, when the 60 million-CU limit activated, and the most recent change used at least 56 million CUs.

The protocol’s per-account write cap remains 12 million CUs. Under the previous 60 million-CU ceiling a single account’s 12 million allowance represented 20% of a block’s compute; at 100 million CUs it represents 12%. That proportional change increases available compute for transactions that touch different accounts but does not expand the compute available to multiple transactions that must update the same writable account, often described as a hot account. There is also a separate 100MB maximum for block accounts-data size delta that can constrain state-heavy workloads even when block compute is available.

Solana’s fee guidance ties optional prioritization fees to a transaction’s requested CU limit and CU price. Higher aggregate block capacity does not automatically change queue priority or fee behavior for transactions targeting the same writable account.

The protocol’s technical proposal notes potential effects of larger blocks, including longer execution time, slower network progress and validator catch-up, and possible unforeseen impacts on infrastructure components beyond validators.

Official upgrade materials do not include before-and-after measurements for transaction inclusion rates, fee levels, block propagation times or replay performance. A single block recorded on Aug. 2 consumed 25,373,012 CUs, processed 1,328 transactions and produced 1,069 successful transactions.

The upgrade raises the theoretical per-block computation ceiling while retaining the 12 million-CU per-account write cap and the 100MB accounts-data delta cap.