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Version: 6.2.0 - 6.2.1

Energy & Bandwidth Guide

Every transaction on TRON consumes resources — Bandwidth for data transmission and Energy for smart contract execution. Understanding these resources is critical for cost optimization.

Resource Types​

ResourcePurposeHow to ObtainConsumed By
BandwidthTransaction data sizeFreeze TRX / Daily free allowanceAll transactions
EnergySmart contract executionFreeze TRX onlyContract calls only

Free Bandwidth​

Every TRON account receives 1,500 free bandwidth points per day (resets every 24 hours). This is enough for ~10 standard TRX transfers.

Bandwidth Cost​

Each transaction consumes bandwidth based on its raw data byte size. If bandwidth is insufficient, TRX is burned for the transaction fee.

Energy Cost​

Energy is required only for smart contract operations (deploy, trigger). The energy cost depends on the contract's computational complexity.

Estimating Energy​

Before calling a smart contract, estimate the energy required:

const result = await tronWeb.transactionBuilder.estimateEnergy(
    'TContractAddr',               // contract address
    'transfer(address,uint256)',   // function selector
    {},                             // options
    [
        { type: 'address', value: 'TReceiverAddr' },
        { type: 'uint256', value: 1000000 },
    ],
    'TCallerAddr',                 // issuer address
);
console.log('Estimated energy:', result.energy_required);

Parameters:

ParameterTypeDescription
contractAddressstringSmart contract address
functionSelectorstringFunction signature (e.g., 'transfer(address,uint256)')
optionsobjectOptions like { callValue, tokenId, tokenValue, feeLimit }
parametersarrayFunction parameters: [{ type, value }]
issuerAddressstringCaller address

Constant Contract Deployment​

For estimating deployment costs:

const result = await tronWeb.transactionBuilder.deployConstantContract({
    input: contractBytecode,
    ownerAddress: 'TDeployerAddr',
    // ABI, feeLimit, etc.
});
console.log('Deploy energy estimate:', result.energy_used);

Querying Account Resources​

const resources = await tronWeb.trx.getAccountResources(address);
console.log(resources);
// {
//   freeNetUsed: 100,        // Free bandwidth used
//   freeNetLimit: 1500,      // Free bandwidth limit
//   NetUsed: 200,            // Staked bandwidth used
//   NetLimit: 5000,          // Staked bandwidth limit
//   EnergyUsed: 10000,       // Energy used
//   EnergyLimit: 50000,      // Energy limit from staking
//   TotalNetLimit: ...,      // Network total bandwidth
//   TotalNetWeight: ...,     // Network total bandwidth weight
//   TotalEnergyLimit: ...,   // Network total energy
//   TotalEnergyWeight: ...,  // Network total energy weight
// }

Resource Calculation​

How Much Energy Do I Get From Staking?​

Your Energy = (Your Frozen TRX / Total Network Frozen TRX) × Total Energy Limit
const resources = await tronWeb.trx.getAccountResources(address);
const myFrozen = 10000_000_000; // 10,000 TRX in SUN
const estimatedEnergy = Math.floor(
    (myFrozen / resources.TotalEnergyWeight) * resources.TotalEnergyLimit
);
console.log('Estimated energy from staking:', estimatedEnergy);

Bandwidth Calculation​

Your Bandwidth = (Your Frozen TRX / Total Network Frozen TRX) × Total Bandwidth Limit

Cost Optimization Tips​

  1. Stake for Energy — Contract-heavy dApps should stake TRX for energy rather than paying per-transaction TRX fees.

  2. Estimate before execution — Always use estimateEnergy before calling contracts to set appropriate feeLimit.

  3. Use free bandwidth — Simple TRX transfers and TRC-10 operations can use the daily free bandwidth allowance.

  4. Batch operations — Combine multiple operations when possible to reduce overhead.

  5. Set appropriate feeLimit — Setting feeLimit too high doesn't cost more, but setting it too low causes transaction failure with fees still consumed.

// Good practice: estimate + buffer
const estimate = await tronWeb.transactionBuilder.estimateEnergy(...);
const safeLimit = Math.ceil(estimate.energy_required * 1.2); // 20% buffer
const energyPrice = 420; // current energy price in SUN

const tx = await tronWeb.transactionBuilder.triggerSmartContract(
    contractAddress,
    'transfer(address,uint256)',
    { feeLimit: safeLimit * energyPrice },
    [{ type: 'address', value: to }, { type: 'uint256', value: amount }],
);