# X_CURRENCY_INVALID

## Means

a `registerCurrency` declaration that cannot become a currency

## Typical cause

a code that is not three uppercase A–Z letters, an `exponent` that is not a whole number in `0…15` (`MAX_MONEY_SCALE`), or an empty `name`. Nothing is defaulted: a guessed exponent of 2 reads `1.23456789` as `1.23` and shifts every stored `minor` by a power of ten

## Fix

`registerCurrency({ code: 'XBT', exponent: 2, name: 'XBT' })` — three A–Z letters, a whole exponent from 0 to 15, and a non-empty name

[i18n, money, time](/error-codes#i18n-money-time)