> For the complete documentation index, see [llms.txt](https://gchandra.gitbook.io/data-warehousing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gchandra.gitbook.io/data-warehousing/data-warehousing-concepts/types-of-facts/periodic-snapshot-vs-additive.md).

# Periodic Snapshot vs Additive

Periodic snapshot fact and additive fact are different concepts, although they may appear similar at first glance.

A **periodic snapshot fact table** is designed to capture a point-in-time snapshot of some measure at regular intervals, typically periodically, such as **daily, weekly, monthly, or quarterly.**

An **additive fact** represents a measure that can be aggregated across all dimensions in a fact table. For example, sales revenue is an additive fact because it can be summed up across all dimensions such as **time, product, region**, etc.

|             | Additive Fact                                                                     | Periodic Snapshot Fact                                                                |
| ----------- | --------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------- |
| Definition  | Represents a measure that can be aggregated across all dimensions in a fact table | Captures a point-in-time snapshot of some measure at regular intervals                |
| Granularity | Can be at any level of granularity                                                | Usually at a higher level of granularity such as daily, weekly, monthly, or quarterly |
| Aggregation | Can be summed up across all dimensions in the fact table                          | Captures the total value of the measure at a specific point in time                   |
| Example     | Sales revenue, profit, number of clicks on a banner ad                            | Monthly sales revenue, quarterly website visits, daily customer support tickets       |