ethereum/go-ethereum · error · Error

This unit doesn't exists, please use the one of the followin

Error message

This unit doesn't exists, please use the one of the following units

What it means

Thrown by getValueOfUnit in web3.js when converting a value to/from wei using a unit name that is not in the unitMap lookup table. The unit is lowercased before lookup, so only the canonical names (wei, kwei/mwei/gwei/..., ether, kether, femtoether, lovelace, shannon, etc.) are accepted. The error message embeds the full JSON of valid units so you can see exactly what is allowed.

Source

Thrown at internal/jsre/deps/web3.js:2135

            return fromAscii(val);
    }

    return fromDecimal(val);
};

/**
 * Returns value of unit in Wei
 *
 * @method getValueOfUnit
 * @param {String} unit the unit to convert to, default ether
 * @returns {BigNumber} value of the unit (in Wei)
 * @throws error if the unit is not correct:w
 */
var getValueOfUnit = function (unit) {
    unit = unit ? unit.toLowerCase() : 'ether';
    var unitValue = unitMap[unit];
    if (unitValue === undefined) {
        throw new Error('This unit doesn\'t exists, please use the one of the following units' + JSON.stringify(unitMap, null, 2));
    }
    return new BigNumber(unitValue, 10);
};

/**
 * Takes a number of wei and converts it to any other ether unit.
 *
 * Possible units are:
 *   SI Short   SI Full        Effigy       Other
 * - kwei       femtoether     babbage
 * - mwei       picoether      lovelace
 * - gwei       nanoether      shannon      nano
 * - --         microether     szabo        micro
 * - --         milliether     finney       milli
 * - ether      --             --
 * - kether                    --           grand
 * - mether
 * - gether

View on GitHub (pinned to 6bb0588ad8)

Solutions

1. Read the unitMap dumped in the error message and use one of those exact unit names (e.g. 'ether', 'gwei', 'kwei').
2. Trim and lowercase the unit string before calling toWei/fromWei.
3. If accepting user input, validate it against a whitelist (Object.keys(web3.eth.unitMap or the printed map) before converting.
4. For 'eth' style shorthand, map it explicitly: unit = unit === 'eth' ? 'ether' : unit.

Example fix

// before
var wei = web3.toWei(amount, 'eth'); // throws

// after
var wei = web3.toWei(amount, 'ether');

var VALID_UNITS = ['wei','kwei','mwei','gwei','szabo','finney','ether','kether','grand']; // or Object.keys(unitMap)
function safeToWei(v, unit) {
  unit = String(unit || 'ether').trim().toLowerCase();
  if (VALID_UNITS.indexOf(unit) === -1) throw new Error('unknown unit: ' + unit);
  return web3.toWei(v, unit);
}

function isKnownUnit(u) {
  return typeof u === 'string' &&
    Object.keys(web3.unitMap || {}).indexOf(u.trim().toLowerCase()) !== -1;
}

When it happens

Trigger: Calling web3.fromWei(x, 'gwei ') / toWei(v, 'GWEI') works, but a typo like 'gwai', an empty-but-non-null string, or a fabricated unit such as 'szabo ' (trailing space) or 'eth' hits unitValue === undefined and throws. Any toWei/fromWei call with an unmapped unit string triggers it.

Common situations: Console scripts in geth attach or dapps using the bundled web3 copy a unit name wrong ('eth' instead of 'ether', 'kwei' misspelled), pass a user-supplied string straight into toWei, or pass a unit with whitespace/casing that was expected to be normalized beyond lowercasing.

Related errors

• Filter ID Error: filter().get() can't be chained synchronous
• invalid iban address
• Contract transaction couldn't be found after 50 blocks
• The contract code couldn't be stored, please check your gas
• Cannot send value to non-payable constructor

AI-assisted analysis of ethereum/go-ethereum@6bb0588ad8 (2026-08-15). Data as JSON: /api/errors/7be34b2b88c60eed. Report an issue: GitHub.