# Unambiguous Monetary Notation

While you can use any `[A-Z]{1,16}(\/\d{1,6})`

asset in your transactions, it is encouraged to use the Unambiguous Monetary Notation if you're dealing with ISO 4217 currencies.

## Specificationโ

An Unambiguous Monetary Notation value is represented as:

`[ASSET/SCALE AMOUNT]`

Where `SCALE`

represent the negative power of ten to multiply the amount with to obtain the decimal value in the asset, and `AMOUNT`

is an unsigned integer. As an example,

`[USD/2 30]`

is equivalent to `USD 30*1E-2`

, i.e `USD 0.30`

, i.e 30 USD cents.

For values where the amount already represents the amount of said asset, a scale of zero should not be represented, e.g. `[JPY 100]`

.

## Rationaleโ

The reason behind this recommendation that using `USD`

in itself is inherently ambiguous. If you see

`USD 100`

It is supposed to represent $100.00 or $1.00? You can't tell without more context - this interpretation is not standardized across payments services providers, some will use strings and happily parse both "100", and "100.30".

By explicitly adding the scale in values, Unambiguous Monetary Notation makes it really hard for amounts to be misinterpreted.