## On this page

Base [StructureDefinition](/content/docs/api/fhir/resources/structuredefinition/index.html) for [Ratio](/content/docs/api/fhir/datatypes/ratio/index.html) Type: A relationship of two [Quantity](/content/docs/api/fhir/datatypes/quantity/index.html) values - expressed as a numerator and a denominator.

- Schema

## Elements

| Name       | Required | Type                                                             | Description                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|------------|----------|------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| id         |          | string                                                           | Unique id for inter-element referencing<br>Details<br>Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.                                                                                                                                                                                                                                                   |
| extension  |          | [Extension](/content/docs/api/fhir/datatypes/extension/index.html)[] | Additional content defined by implementations<br>Details<br>May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.<br>There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
| numerator   |          | [Quantity](/content/docs/api/fhir/datatypes/quantity/index.html)          | Numerator value<br>Details<br>The value of the numerator.                                                                                                                                                                                                                                                                                                                                                                                    |
| denominator |          | [Quantity](/content/docs/api/fhir/datatypes/quantity/index.html)          | Denominator value<br>Details<br>The value of the denominator.                                                                                                                                                                                                                                                                                                                                                                                  |

- [Elements](/content/docs/api/fhir/datatypes/ratio#elements/index.html)