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Massa Units

All Massa values that are being used or returned by web3 (gas, fees, coins and rolls) are expressed via BigInt's. Massa-web3 has however a few convenience methods and converters that might come handy. Below is a summary of available methods:

  • Rolls: expressed in BigInt's. For Rolls there is no metric system as rolls are unit-less. 10 rolls is to be represented by a BigInt containing 10. Example:
const rolls = BigInt(10);
// or. ...
const rolls = 10n;
  • Gas/MaxGas: expressed in BigInt's. For Gas/MaxGas there is no metric system as gas is unit-less. The gas represents the computational units required for a given operation to be executed by the network. Example:
const gas = BigInt(2000000);
// or. ...
const gas = 2000000n;
  • Coins/Fees: expressed in BigInt's. Coins/fees do however have a metric system behind them. The smallest unit is 10-9 Massa. All coins/fees are to be expressed as integers scaled by 109 and this way consumed by the network json-rpc protocol. Since gas/fees are to be used as BigInt's web3 adds in a few convenience utils allowing smaller units (e.g. 0.5 Massa) to be expressed.

The util function fromMAS and toMAS are used exactly for the latter purpose. fromMAS receives any amount of type number | string | BigNumber | bigint and returns a scaled bigint for ready use. toMAS on the contrary converts any amount from nanoMassa to Massa and returns a BigNumber representing the amount as a decimal.


const coinsToTransfer = fromMAS("0.5"); // half a massa
// or. ...
const coinsToTransfer = 500n * MassaUnits.mMassa; // half a massa
const coinsToTransfer = fromMAS("1"); // one massa
// or. ...
const coinsToTransfer = 1n * MassaUnits.oneMassa; // one massa

Web3 exposes a collection MassaUnits which has three convenience BigInt constants that could be used for amount scaling:

  • MassaUnits.oneMassa = 10910^{9}
  • MassaUnits.mMassa = 10610^{6}
  • MassaUnits.uMassa = 10310^{3}