Keep enough TRX to cover the network’s estimate for your swap, plus a small buffer; there is no fixed fee for every trade. On TRON, a token swap runs through a smart contract, which is software that carries out the trade. The network may charge TRX when your account lacks the resources to run it.
Why does a token swap need TRX?
A centralised exchange handles network costs behind the scenes, but a wallet transaction uses TRON’s own resources. Bandwidth covers the space a transaction takes up, while Energy pays for the contract’s computing work. A swap of USDT or another TRC-20 token uses a contract call, so Energy is usually the bigger variable.
If you lack enough Bandwidth or Energy, the network can burn TRX from your wallet to cover the shortfall. The current documented rates are 1,000 sun per Bandwidth and 100 sun per Energy; one sun is one-millionth of a TRX. These rates can change, so check the official resource fee guide for current values.
How can you estimate a useful reserve?
Use the wallet’s transaction estimate as your starting point, then check whether your account has available Energy and Bandwidth. An estimate can change with the contract’s activity and with resources provided by the contract’s creator. So a swap that costs little from one account may need more TRX from another.
For example, if a call uses 65,000 Energy and your account has none available, the documented rate works out to 6.5 TRX for that Energy. This is an illustration, not a quoted fee: the actual Energy use varies, and the call may also need Bandwidth. Keep a little more than the estimate, but avoid treating one example as a universal reserve.
A common mistake is to send every last TRX out of the wallet because the token balance looks sufficient. Leave enough TRX for the network estimate and a buffer; otherwise, the transaction may fail for lack of resources. If the account has no available TRX, it cannot pay a TRX shortfall.
What should you check before signing?
Read the wallet’s estimate and confirm which token and amount the transaction will use. If the estimate is high, check the account’s available resources and consider waiting for them to recover; staked Bandwidth and Energy gradually return over 24 hours. Staking TRX can provide resources, but unstaking takes time, so it is not a quick fix for a swap you want to make now. TRON’s staking guide explains the recovery and unstaking rules.
For the connection setup itself, how TronLink connects for a TRON swap explains that step by step. Once connected, check the estimate before signing and keep enough TRX available to cover any shortfall. That simple reserve check helps prevent a failed trade.