> For the complete documentation index, see [llms.txt](https://docs.fabricplan.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fabricplan.com/planning-sheets/concepts/forecasting/reforecasting.md). # Reforecasting ### Update Forecast Periods with Reforecasting Reforecasting lets you update forecast periods by using values from existing periods as a baseline. You can copy values from a source period to a target period, and then apply adjustments, such as growth assumptions, to create an updated forecast with a time extension. Reforecasting is useful when you extend the forecast horizon (planning period) after closing a period and need to seed the newly opened period with the latest actual values. Alternatively, it also allows you to retain the forecast values you previously entered in the closing period. ### How reforecasting works Reforecasting follows these steps: 1. Close the completed period and extend the forecast horizon. 2. Select the newly opened forecast period as the target period. 3. Select the measure and source period to use as the baseline. 4. Copy the source values to the target period. 5. Apply adjustments to the target values, such as a growth assumption. ### When to use reforecasting Use reforecasting when you need to: * Input values in the opened forecast period with values from an existing period. * Use recent actuals as a baseline for future forecasts. * Update forecast values after closing a period. * Apply growth assumptions to newly seeded forecast values. * Maintain a continuous forecast horizon as actual periods become available. * Distribute forecast deficit value to open periods in the forecast measures. ### Key takeaway Reforecasting lets you use existing planning values to seed future forecast periods and apply updated assumptions. When you combine reforecasting with period closing and forecast extension, you can maintain a continuous forecast horizon as actuals become available. Deficit distribution also comes handy when you want to retain the total (original) forecast for the year by spreading the delta in the open period. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.fabricplan.com/planning-sheets/concepts/forecasting/reforecasting.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.