> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gobl.org/llms.txt
> Use this file to discover all available pages before exploring further.

# ExchangeRate

ExchangeRate contains data on the rate to be used when converting amounts from one currency into another.

## Schema ID

`https://gobl.org/draft-0/currency/exchange-rate`

## Properties

| Title  | Property | Type                                    | Description                                                                                                                                                                         |
| ------ | -------- | --------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| From   | `from`   | [currency.Code](/draft-0/currency/code) | Currency code this will be converted from.                                                                                                                                          |
| To     | `to`     | [currency.Code](/draft-0/currency/code) | Currency code this exchange rate will convert into.                                                                                                                                 |
| At     | `at`     | [cal.DateTime](/draft-0/cal/date_time)  | At represents the effective date and time at which the exchange rate is determined by the source. The time may be zero if referring to a specific day only.                         |
| Source | `source` | [cbc.Key](/draft-0/cbc/key)             | Source key provides a reference to the source the exchange rate was obtained from. Typically this will be determined by an application used to update exchange rates automatically. |
| Amount | `amount` | [num.Amount](/draft-0/num/amount)       | How much is 1 of the "from" currency worth in the "to" currency.                                                                                                                    |

## Validation Rules

| Field    | Test                                                                  | Validation Code / Message                                       |
| -------- | --------------------------------------------------------------------- | --------------------------------------------------------------- |
| `from`   | <ul class="gobl-test"><li class="gobl-test-present">Present</li></ul> | `GOBL-CURRENCY-EXCHANGERATE-01`<br />From currency is required  |
| `to`     | <ul class="gobl-test"><li class="gobl-test-present">Present</li></ul> | `GOBL-CURRENCY-EXCHANGERATE-02`<br />To currency is required    |
| `at`     | <ul class="gobl-test"><li>Not zero</li></ul>                          | `GOBL-CURRENCY-EXCHANGERATE-03`<br />Date/time must not be zero |
| `amount` | <ul class="gobl-test"><li>Min 0</li></ul>                             | `GOBL-CURRENCY-EXCHANGERATE-04`<br />Amount must be positive    |