Fusaka introduced the first meaningful evolution of Ethereum’s blob fee mechanics since Dencun. On the surface, nothing dramatic changed. Blobs still have their own fee market, with a base fee that adjusts based on supply and demand. But Fusaka added a second pricing constraint that alters how the effective blob price is determined.
The Key Change: A Blob Base Fee Floor
Before Fusaka, the blob base fee was entirely governed by blob usage. If demand fell, the base fee could drop very low. Fusaka introduced a floor on blob pricing tied to the execution layer base fee:
effectiveBlobBaseFee = max(
blobBaseFee,
blobFloor(executionBaseFee)
)
Where:
blobFloor(executionBaseFee) = executionBaseFee / 16
This means the effective blob base fee used for payment is whichever number is higher: the 1559 style blob market’s base fee, or the floor imposed by the execution base fee.
Fusaka therefore creates a soft coupling between the previous block’s execution gas and the blob gas, even though blobs remain a separate fee market.
Why Add a Floor at All?
Since the Pectra blob prices have basically collapsed to 1 wei, blobs have become artificially cheap relative to execution gas, distorting incentives for how Layer 2s post data.
The floor ensures blob pricing remains within a reasonable band relative to the rest of the network’s pricing dynamics.
What Developers Need to Update
If you’re building anything that interacts with blob indexers, explorers, fee estimators, or L2 infrastructure, there are three concrete changes to make.
1. Treat the blob base fee as two values
Store or compute:
blobBaseFeeblobFloor(executionBaseFee)effectiveBlobBaseFee(the max of the two)
The effective fee is what users actually pay.
2. Don’t assume low-demand periods mean cheap blobs
The floor prevents blob prices from dropping below baseFee / 16, so
blobs will no longer tail off to near-zero in quiet periods.
3. Expect the blob market to be smoother but less independent
Blobs still adjust based on blob demand, but the execution base fee now sets a lower bound on how low blob prices can go. That makes pricing more predictable but also more coupled to general network conditions.
Example
Let’s assume a 21,000 gas call with a single blob costing 131,072 blob gas and a fixed 1 gwei prioirty fee and ETH price: $3,000 USD
| Scenario | Exec base fee | Raw blob base fee | Floor = base/16 | Effective blob base fee | Floor active? | Total Gas Cost (gwei) | Total Blob Cost (gwei) | Total Cost (gwei) | Approx USD ($) |
|---|---|---|---|---|---|---|---|---|---|
| A: No floor | 30 | 5 | 1.875 | 5 | No | 651,000 | 655,360 | 1,343,000 | $4.03 |
| B: Floor active | 80 | 2 | 5 | 5 | Yes | 1,701,000 | 655,360 | 2,393,000 | $7.18 |
| C: High-demand blobs | 40 | 20 | 2.5 | 20 | No | 861,000 | 2,621,440 | 3,523,440 | $10.57 |
| D: High-demand gas | 100 | 6 | 6.25 | 6.25 | Yes | 2,121,000 | 819,950 | 3,248,950 | $9.75 |
Summary
Fusaka didn’t overhaul the blob market, but it added one crucial rule:
Blob fees now have a floor equal to
execution_base_fee / 16, and the effective blob price is the maximum of the raw blob base fee and this floor.