Fees & Gas in Dollars
Gas is paid in USDn, a stable dollar. This changes how you think about fees.
The formula
fee = gasUsed × (baseFee + priorityFee), exactly as on Ethereum after EIP-1559, with two differences:
- The base fee has a floor of 1,000 gwei USDn (0.000001 USDn per gas). It rises under congestion by up to 12.5% per block and falls back to the floor when blocks are under half full.
- Nothing is burned. Base fee and tip both go to the block's fee sink and are split 50% Carbon Fund, 40% miners, 10% proposer.
What things cost at the floor
| Action | Gas | Fee (1,000 gwei + 1 gwei tip) |
|---|---|---|
| USDn transfer | 21,000 | 0.021 USDn |
| ERC-20 transfer | ~50,000 | 0.05 USDn |
| Uniswap-style swap | ~150,000 | 0.15 USDn |
| NFT mint | ~80,000 | 0.08 USDn |
| Deploy 4 KB contract | ~1,000,000 | 1 USDn |
Block gas limit 30,000,000; block time 3 s; about 1,400 transfers or 200 swaps per block at capacity.
Why a floor
Without one, an idle chain's base fee decays to zero and state bloat becomes free. The floor keeps fees meaningful for the Carbon Fund and for miners at any volume, and two cents per transfer is well below the level at which users notice.
Budgeting
Because the unit is a dollar, you can write budgets like "this agent may spend 5 USDn per day" without a price feed. Expected fee = expected gas × (current base fee + your tip); read the base fee from eth_getBlockByNumber("latest").baseFeePerGas or eth_feeHistory.
Priority fees
There is no MEV auction. Blocks are built by the in-turn validator from the transaction pool in fee order. A tip of 1 gwei is plenty when blocks are not full; raise it under congestion.
Where your fee goes, per transaction
For a 0.021 USDn transfer:
| Recipient | Amount |
|---|---|
| Carbon Fund | 0.0105 USDn |
| Miner pool (per accepted share) | 0.0084 USDn |
| Proposing validator | 0.0021 USDn |
You can verify the Carbon Fund credit for any block: see Fee Accounting.