---
type: "fhirpath-function"
title: "FHIRPath Function: hourOf"
function: "hourOf"
category: "Utility functions"
section: "5.10.8.4"
source: "fhirpath/functions.json"
---
# FHIRPath Function: hourOf
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## Summary
- **Category**: Utility functions
- **Section**: `5.10.8.4`
- **Return Type**: `Integer`
- **Empty Input Result**: `empty`
- **Errors on Multiple Input**: `true`
## Description
If the input collection contains a single Date, DateTime or Time, this function will return the hour component.
## Arguments
- none
## Type Mapping
- `Date-Integer`
- `DateTime-Integer`
- `Time-Integer`
## Example
```fhirpath
@2014-01-05T10:30:00.000.hourOf() // 10
```