Every time a user sends rBTC, transfers DOC, or interacts with Money On Chain, they must pay a fee for using the Rootstock network.
These fees are paid in rBTC, Rootstock’s native asset pegged 1:1 to Bitcoin. For this reason, even if someone holds DOC, MOC, or BPRO in their wallet, they still need a small amount of rBTC to perform transactions.
But how is the final fee calculated?
Gas is the unit used to measure the computational work required to process a transaction.
Sending rBTC from one wallet to another is a relatively simple operation. By contrast, using a DeFi protocol may require the network to retrieve information, perform calculations, and execute multiple smart contract instructions.
This is why not every transaction consumes the same amount of gas.
The fee is calculated using the following formula: Transaction fee=Gas used×Gas price
According to the Rootstock documentation, gas fees are paid in rBTC and collected by
To understand the calculation, three concepts must be distinguished:
The gas limit is not necessarily the amount for which the user will be charged. If the wallet sets a limit of 100,000 gas units but the transaction uses only 70,000, the fee is calculated using the 70,000 units consumed.
The unused portion is not charged.
Imagine a simple rBTC transfer with the following values:
The calculation would be: 21,000×0.06=1,260 gwei
Because 1 gwei is equivalent to 0.000000001 rBTC, the fee would be: 1,260 gwei=0.00000126 rBTC
Its value in US dollars would depend on Bitcoin’s market price at that time.
This example is for illustrative purposes only. Gas prices can change, so users should always review the estimate displayed by their wallet before confirming a transaction.
rBTC is the native asset of Rootstock. Sending it between two addresses requires a basic network operation.
DOC, MOC, and BPRO, however, are managed through smart contracts. When transferring one of these tokens, the network must execute additional instructions, verify balances, and update information recorded on the blockchain.
An operation within Money On Chain may involve even more steps, such as retrieving prices, performing calculations, or minting and redeeming tokens.
For this reason, transferring DOC and completing an operation through the protocol may have different costs, even when the economic value involved is similar.
If an address does not hold enough rBTC, it cannot send DOC, MOC, or BPRO, or interact with Money On Chain.
The gas limit may also be insufficient. In that case, the transaction can fail, and the gas consumed during the attempt is not refunded because the network has already used computational resources to process it.
Users should generally follow the gas limit and gas price suggested by their wallet unless they understand how to configure these values manually.
Before requesting the user’s signature, the wallet estimates the gas required and displays an approximate maximum cost.
Once the transaction has been processed, users can enter its transaction hash into a Rootstock block explorer to check:
A network fee should be distinguished from any conditions or charges associated with a specific application. Gas is paid for using Rootstock and having the transaction processed by the network.
To operate more safely on Rootstock:
Understanding gas used, gas price, and gas limit makes it easier to anticipate transaction costs and avoid errors when using Money On Chain and other applications built on Rootstock.
