Arc denominates all transaction fees in
USDC, the native gas token. The fee
market uses an EIP-1559 pricing model
combined with exponentially weighted moving average (EWMA) smoothing — a
technique that calculates the base fee from a weighted running average of recent
block utilization, giving more weight to recent blocks and less to older ones.
This produces stable, predictable gas costs.
For the mechanism design behind these parameters, see
Stable fee design.
Fee parameters
| Parameter | Value | Notes |
|---|
| Gas unit | USDC (18 decimals) | Native gas accounting precision |
| Pricing model | EIP-1559 + EWMA smoothing | Replaces per-block recalculation with a moving average |
| Base fee target | ~$0.01 per transaction | Design-time target under normal load |
| Minimum base fee (testnet) | 20 Gwei | Floor enforced by the protocol |
| Maximum base fee | 1e-3 USDC (~$0.001 per gas unit) | Hard ceiling that bounds worst-case cost |
| Gas throughput | 20 M gas/sec | Protocol-level capacity limit |
| Smoothing method | EWMA of block utilization | Short spikes do not propagate into sudden fee jumps |
The 18-decimal precision listed above applies to Arc’s native gas accounting.
USDC on Arc also provides a standard ERC-20 interface with 6
decimals for
application-level transfers and balance display. These are not two separate
tokens — they share the same underlying balance. See Contract
addresses for the ERC-20 address. Submitting transactions
Follow these practices to ensure timely transaction inclusion on Arc.
Set an adequate max fee
Set maxFeePerGas to at least 20 Gwei. Transactions submitted below this
floor may remain pending indefinitely or fail outright.
import { ethers } from "ethers";
const provider = new ethers.JsonRpcProvider("https://rpc.testnet.arc.network");
const wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);
const tx = await wallet.sendTransaction({
to: recipient,
value: ethers.parseUnits("1", 6), // 1 USDC via native send
maxFeePerGas: ethers.parseUnits("20", "gwei"),
});
maxPriorityFeePerGas (the EIP-1559 tip) to incentivize sequencer
inclusion. A value of 0 Gwei is accepted, but a small tip (for example, 1
Gwei) can improve inclusion time during high-utilization periods.
Fetch the current base fee
Query the Arc RPC before submitting to get the latest fee data. Two standard
methods are available:
| Method | Returns | Use case |
|---|
eth_gasPrice | Suggested gas price as a single value | Quick estimation for simple transactions |
eth_feeHistory | Base fee and priority fee history over recent blocks | Fine-grained estimation when you need historical context |
import { ethers } from "ethers";
const provider = new ethers.JsonRpcProvider("https://rpc.testnet.arc.network");
// Fetch current gas price
// Returns: hex string (e.g., "0x4a817c800" = 20 Gwei)
const gasPrice: string = await provider.send("eth_gasPrice", []);
// Fetch fee history for the last 5 blocks
// Returns: { baseFeePerGas: string[], gasUsedRatio: number[], reward: string[][] }
const feeHistory = await provider.send("eth_feeHistory", [
"0x5", // block count
"latest", // newest block
[25, 50, 75], // percentiles
]);
Display fees in USDC
Because Arc denominates gas in USDC, surface fee estimates to users in dollar
terms rather than raw Gwei. This avoids confusion and aligns with the
stablecoin-native model.
Common errors
| Error | Cause | Resolution |
|---|
transaction underpriced | maxFeePerGas is below the 20 Gwei minimum base fee floor | Increase maxFeePerGas to at least ethers.parseUnits("20", "gwei") and resubmit |
intrinsic gas too low | Gas limit is lower than the intrinsic cost of the transaction | Set the gas limit to at least 21,000 for simple transfers; use eth_estimateGas for contract calls |
insufficient funds for gas * price + value | The sending account’s USDC balance cannot cover both the transfer value and the gas fee | Fund the account with enough USDC to cover the total cost (value + maxFeePerGas x gasLimit) |
Monitoring
View real-time gas metrics and recent averages using the
Arc Gas Tracker. The tracker displays
current base fee, historical trends, and per-block utilization.
The parameters on this page reflect the current Arc Testnet configuration.
Values such as the minimum base fee, maximum base fee, and throughput limits
may change before mainnet launch.
