---
url: >-
  https://adk.nht.io/api/@nhtio/adk/batteries/tools/datetime_extended/variables/datePeriodTool.md
description: Get the start or end of a time period containing a given date.
---

# Variable: datePeriodTool

```ts
const datePeriodTool: Tool<SpooledArtifact>;
```

Defined in: [batteries/tools/datetime\_extended/index.ts:289](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/batteries/tools/datetime_extended/index.ts#L289)

Get the start or end of a time period containing a given date.

## Remarks

Periods: `day`, `week`, `isoweek` (Monday-start), `month`, `quarter`, `year`. Quarter and year
honour `fiscal_year_start_month` for fiscal calendars (default: 1 = calendar year).