Gas and Fees

Gas

When executing smart contracts, the EVM requires the amount of work paid in gas. The “work” includes computation, state transitions, and storage. Gas is the unit of measurement used to charge a fee per opcode executed by the EVM. Each opcode code has a defined gas cost. Gas reflects the cost necessary to pay for the computational resources used to process transactions.

Weibar

Gas information for EVM operations is returned in weibar (introduced in HIP-410).

• 1 weibar = 10^-18 HBAR

• 1 tinybar = 10^10 weibar

As noted in HIP-410, this maximizes compatibility with third-party tools that expect ether units to be operated on in fractions of 10^18, also known as a Wei.

Gas Schedule and Fee Calculation

Gas charges apply to ContractCall, ContractCreate, and EthereumTransaction. Other smart contract-related transactions (e.g., ContractDelete, ContractGetInfo) use standard Hedera network, node, and service fees in HBAR.

Gas fees for EVM transactions constist of:

• Intrinsic Gas: The minimum amount of gas required to execute a transaction.

• EVM opcode Gas: The gas required to execute the defined opcodes for the smart contract call.

• Hedera System Contract Gas: The required gas that is associated with a Hedera-defined transaction, like using the Hedera Token Service system contract that allows you to burn (TokenBurnTransaction) or mint (TokenMintTransaction) a token.

Intrinsic Gas

A transaction submitted to the smart contract service must be sent with enough gas to cover intrinsic gas. With the Cancun fork of the EVM update, intrinsic gas is calculated as:

21000 + 4 x (number of zeros bytes) + 16 x (number of non-zeros bytes)= intrinsic gas

• 21,000: The base gas cost for any transaction.

• 4 x (zero bytes): The cost of each zero byte in the transaction payload.

• 16 x (number of non-zero bytes): The cost for each non-zero byte in the transaction payload.

If insufficient gas is submitted, the transaction will fail during precheck and no record will be created.

Note

This applies to both standard transactions and jumbo EthereumTransactions introduced by HIP-1086, which allow larger callData payloads.

EVM Opcode Gas

Execution costs in the EVM include both fixed and dynamic costs:

• Fixed Cost: Base cost per opcode execution.

• Dynamic Cost: Varies by parameters (e.g., cold vs warm storage access).

Example: For the SLOAD opcode, which loads data from storage:

• Fixed Cost: 100 gas units (base cost per execution)

• Dynamic Cost (Cold Access): 2,100 gas units (first-time access to the storage slot)

• Dynamic Cost (Warm Access): 100 gas units (subsequent access within the transaction)

If SLOAD accesses a storage slot twice within the same transaction, the total gas cost would be calculated as follows:

1. First Access (Cold) = 100 + 2,100 = 2,200 gas

2. Second Access (Warm) = 100 + 100 = 200 gas

3. Final Gas Cost Total = 2,200 + 200 = 2,400 gas

📣 Explore opcodes in Cancun fork.

Hedera System Contract Gas

Hedera system contract gas fees apply only when using a native Hedera service. They are calculated by converting the transaction cost in USD to gas using a set conversion rat, then adding 20% surcharge was added for overhead and variations in gas usage.

Example: For a $0.10 transaction with a conversion rate of 1,000,000 gas per USD:

• Base Gas Cost = 0.10 × 1,000,000 = 100,000 gas

• Total Gas Cost = 100,000 × 1.2 = 120,000 gas

Final gas cost total = 120,000 gas

System Contract View Functions

The gas requirements for HTS view functions can be calculated in a slightly modified manner. The transaction type of getTokenInfo can be used and a nominal price need not be calculated. This implies that converting the fee into HBAR is not necessary as the canonical price ($0.0001) can be directly converted into gas by using the conversion factor of 852 tinycents. Add 20% markup. Thus gas cost is:

• Base gas cost = (1000000 + 852000 - 1) * 1000 / 852000 = 2173 gas

• Total Gas Cost = 2173 x 1.2 = 2607 gas

Final gas cost total = 2607 gas

Example System Contracts:

• Hedera Token Service

• Pseudo Random Number Generator (PRNG)

• Exchange Rate

Learn More: Our detailed gas calculation reference explains the precise steps for calculating gas fees on Hedera.

Gas for Jumbo Transactions

Jumbo EthereumTransaction that include large callData under HIP-1086 follow the same gas model as standard EVM transactions. This gas pricing applies only to EthereumTransaction type, standard HAPI transactions are unaffected.

Formula

The gas cost for callData is based on byte content:

callData gas = (4 × zero bytes) + (16 × non-zero bytes)

This is added to the base gas and execution gas to calculate the total gas required.

📣 Learn more about Ethereum jumbo transactions

Example Calculation

For 100KB of callData with 10,000 zero bytes and 90,000 non-zero bytes:

• Zero byte gas: 4 × 10,000 = 40,000

• Non-zero byte gas: 16 × 90,000 = 1,440,000

• Total callData gas = 1,480,000

Ensure both gasLimit (RLP) and maxGasAllowance (wrapper) are set high enough to cover the total.

🔹 Size Caps: Jumbo EthereumTransactions are capped at 24KB (creation) and 128KB (call). Larger payloads require callDataFileId. 🔹 Throttling: Jumbo transactions are subject to dedicated throttling (bytes/sec per node).

Gas Limit

The gas limit is the maximum amount of gas you are willing to pay for an operation.

The current opcode gas fees are reflective as of the 0.22 Hedera Service release.

Operation	Cancun Cost (Gas)	Current Hedera (Gas)
Code deposit	200 * bytes	200 * bytes
BALANCE (cold account)	2600	2600
BALANCE (warm account)	100	100
EXP	10 + 50/byte	10 + 50/byte
EXTCODECOPY (cold account)	2600 + Mem	2600 + Mem
EXTCODECOPY (warm account)	100 + Mem	100 + Mem
EXTCODEHASH (cold account)	2600	2600
EXTCODEHASH (warm account)	100	100
EXTCODESIZE (cold account)	2600	2600
EXTCODESIZE (warm account)	100	100
LOG0, LOG1, LOG2, LOG3, LOG4	375 + 375*topics + data Mem	375 + 375*topics + data Mem
SLOAD (cold slot)	2100	2100
SLOAD (warm slot)	100	100
SSTORE (new slot)	22,100	22,100
SSTORE (existing slot, cold access)	2,900	2,900
SSTORE (existing slot, warm access)	100	100
SSTORE refund	As specified by the EVM	As specified by the EVM
CALL et al. (cold recipient)	2,600	2,600
CALL et al. (warm recipient)	100	100
CALL et al. HBAR/ETH Transfer Surcharge	9,000	9,000
SELFDESTRUCT (cold beneficiary)	2600	2600
SELFDESTRUCT (warm beneficiary)	0	0
TSTORE	100	100
TLOAD	100	100
MCOPY	3 + 3*words_copied + memory_expansion_cost	3 + 3*words_copied + memory_expansion_cost

The terms 'warm' and 'cold' in the above table correspond with whether the account or storage slot has been read or written to within the current smart contract transaction, even within a child call frame.

'CALL et al.' includes with limitation: CALL, CALLCODE, DELEGATECALL, and STATICCALL

Reference: HIP-206, HIP-865

Gas Per Second Throttling

Most EVM-compatible networks use a per-block gas limit to control resource allocation and limit block validation time, enabling miner nodes to produce new blocks quickly. While Hedera lacks blocks and miners, it must still manage resource use over time.

For smart contract transactions, gas is a more effective measure of transaction complexity than transaction count. To balance flexibility and resource management, Hedera mirrors Ethereum's approach by setting transaction limits based on gas consumption (for ContractCreate, ContractCall, and ContractCallLocalQuery), alongside per-transaction limits. This dual method enables precise regulation of smart contract executions.

The Hedera network has implemented a system gas throttle of 15 million gas per second in the Hedera Service release 0.22.

Gas Reservation and Unused Gas Refund

Hedera throttles transactions before consensus, and nodes limit the number of transactions they can submit to the network. Then, at consensus time, if the maximum number of transactions is exceeded, the excess transactions are not evaluated and are canceled with a busy state. Throttling by variable gas amounts provides challenges to this system, where the nodes only submit a share of their transaction limit.

To address this, throttling will be based on a two-tiered gas measuring system: pre-consensus and post-consensus. Pre-consensus throttling will use the gasLimit field specified in the transaction. Post-consensus will use the actual evaluated amount of gas the transaction consumes, allowing for dynamic adjustments in the system. It is impossible to know the actual evaluated gas pre-consensus because the network state can directly impact the flow of the transaction, which is why pre-consensus uses the gasLimit field and will be referred to as the gas reservation.

Contract query requests are unique and bypass the consensus stage altogether. These requests are executed solely on the local node that receives them and only influence that specific node's precheck throttle. On the other hand, standard contract transactions go through both the precheck and consensus stages and are subject to both sets of throttle limits. The throttle limits for precheck and consensus may be set to different values.

In order to ensure that the transactions can execute properly, setting a higher gas reservation than will be consumed by execution is common. On Ethereum Mainnet, the entire reservation is charged to the account before execution, and the unused portion of the reservation is credited back. However, Ethereum utilizes a memory pool (mempool) and does transaction ordering at block production time, allowing the block limit to be based only on used and not reserved gas.

To help prevent over-reservation, Hedera restricts the amount of unused gas that can be refunded to a maximum of 20% of the original gas reservation. This effectively means users will be charged for at least 80% of their initial reservation, regardless of actual usage. This rule is designed to incentivize users to make more accurate gas estimates.

For example, if you initially reserve 5 million gas units for creating a smart contract but end up using only 2 million, Hedera will refund you 1 million gas units, or 20% of your initial reservation. This setup balances the network's resource management while incentivizing users to be as accurate as possible in their gas estimations.

Maximum Gas Per Transaction

Each transaction on Hedera is capped by a per-transaction gas limit. If a transaction’s gasLimit exceeds this cap, it is rejected during precheck with the INDIVIDUAL_TX_GAS_LIMIT_EXCEEDED error and does not proceed to consensus. This gas metering approach ensures efficient resource use, preventing excessive consumption while allowing flexibility for larger, more complex smart contracts.

Gas throttle per contract call and contract create 15 million gas per second.

Reference: HIP-185