> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cosmos.network/llms.txt
> Use this file to discover all available pages before exploring further.

# EIP-1559 Fee Market

> Understanding dynamic fee pricing and the EIP-1559 mechanism in Cosmos EVM chains

## Overview

[EIP-1559](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1559.md) revolutionizes transaction fee mechanics by replacing the single gas price auction model with a dual-fee structure. This creates more predictable fees and improved network efficiency for EVM-compatible chains.

## Core Concepts

### Dual-Fee Structure

Before EIP-1559, fees were simple:

```
fee = gasPrice * gasLimit
```

With EIP-1559, fees have two components:

```
fee = (baseFee + priorityTip) * gasLimit
```

where:

* `baseFee`: Protocol-determined minimum price per gas unit
* `priorityTip`: Optional fee for transaction prioritization

<Info>
  The Cosmos SDK uses different terminology than Ethereum. What Ethereum calls `gasLimit` is `gasWanted` in Cosmos. You'll encounter both terms in the Cosmos EVM as it bridges Ethereum and Cosmos SDK concepts.
</Info>

### Base Fee Mechanism

The base fee is the minimum price per unit of gas required for transaction inclusion. It automatically adjusts each block based on network utilization.

#### Adjustment Formula

```
NewBaseFee = BaseFee × (1 + (|GasUsed - GasTarget| / GasTarget / Denominator))
```

The adjustment direction depends on block utilization:

* **Increases** when `gasUsed > gasTarget` (congested)
* **Decreases** when `gasUsed < gasTarget` (underutilized)
* **Remains stable** when `gasUsed == gasTarget` (optimal)

#### Example Calculation

With standard Ethereum parameters:

* Current base fee: 1000 units
* Block capacity: 10M gas
* Target (50%): 5M gas
* Actual usage: 8M gas (80% full)
* Denominator: 8

```
Adjustment = (8M - 5M) / 5M / 8 = 0.075 (7.5% increase)
New base fee = 1000 × 1.075 = 1075 units
```

### Target Utilization

The target utilization determines the optimal block fullness:

```
Target Gas = MaxBlockGas / ElasticityMultiplier
Target Utilization % = 100 / ElasticityMultiplier
```

Common configurations:

* `ElasticityMultiplier = 2`: 50% target (Ethereum standard)
* `ElasticityMultiplier = 4`: 25% target (aggressive pricing)
* `ElasticityMultiplier = 1`: 100% target (maximum throughput)

### Priority Tips and MEV

The `max_priority_fee_per_gas` (tip) serves as an incentive for validators to include transactions faster. However, in Cosmos SDK implementations:

* Transaction prioritization is limited compared to Ethereum
* Tips may have minimal effect on inclusion order
* MEV opportunities are generally reduced

### Effective Gas Price

For EIP-1559 transactions, users specify two limits:

* `maxFeePerGas`: Maximum total they're willing to pay
* `maxPriorityFeePerGas`: Maximum tip for validators

The effective price becomes:

```
effectiveGasPrice = min(baseFee + maxPriorityFeePerGas, maxFeePerGas)
```

This ensures users never pay more than their specified maximum while allowing for priority fees when network conditions permit.

## Fee Calculation Examples

### Low Activity Period

* Base fee: 100 gwei
* User sets: maxFeePerGas = 200 gwei, maxPriorityFeePerGas = 2 gwei
* Effective price: 100 + 2 = 102 gwei
* User pays: 102 gwei (well below their 200 gwei max)

### High Congestion

* Base fee: 180 gwei
* User sets: maxFeePerGas = 200 gwei, maxPriorityFeePerGas = 30 gwei
* Effective price: min(180 + 30, 200) = 200 gwei
* User pays: 200 gwei (capped at their maximum)

## Minimum Gas Prices

The fee market enforces multiple price floors:

### Local vs. Global Minimums

1. **Local minimum**: Set by individual validators in node configuration
2. **Global minimum**: Set as the `MinGasPrice` parameter via governance
3. **Base fee**: Current protocol-calculated minimum

The effective minimum is always the highest of these three values.

<Alert>
  If the base fee falls below the global `MinGasPrice`, it's automatically raised to `MinGasPrice`. This prevents the base fee from dropping below the spam prevention threshold.
</Alert>

## Benefits of EIP-1559

### For Users

* **Predictable fees**: Base fee is known before submitting
* **Better UX**: Wallets can reliably estimate costs
* **Fair pricing**: All users in a block pay similar rates
* **Protection**: MaxFeePerGas prevents overpayment

### For Networks

* **Automatic adjustment**: No manual intervention needed
* **Spam resistance**: Dynamic fees deter attacks
* **Optimal utilization**: Targets efficient block usage
* **Economic stability**: Predictable fee revenue

### For Developers

* **Simplified estimation**: Base fee is protocol-provided
* **Better tools**: Standard APIs for fee data
* **Consistent behavior**: Across EVM-compatible chains

## Common Misconceptions

### "Tips Always Speed Up Transactions"

In Cosmos SDK chains, transaction ordering is often FIFO within the mempool, making tips less effective than on Ethereum mainnet.

### "Base Fee Always Burns"

While Ethereum burns the base fee, Cosmos EVM chains may distribute it differently based on their economic model.

### "EIP-1559 Eliminates Fee Spikes"

It smooths volatility but can't prevent spikes during extreme congestion. The adjustment rate is intentionally limited.

## Further Reading

* [Original EIP-1559 Proposal](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1559.md)
* [Ethereum Gas Tracker](https://etherscan.io/gastracker)
* [cosmos/evm Fee Market Module](https://github.com/cosmos/evm/tree/v0.4.1/x/feemarket)
* [Understanding Gas and Fees](/evm/next/documentation/concepts/gas-and-fees)