> For the complete documentation index, see [llms.txt](https://help.modelreef.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.modelreef.io/syntax/variables-syntax/manual-time-series-editing.md).

# Manual Time Series Editing

This article explains **Manual Time Series Editing** for variables in Model Reef.

You will learn:

* When manual editing is available.
* How to change values across periods.
* How manual edits interact with presets, imports and formulas.

Manual editing lets you shape a variable's behaviour period by period without writing a custom formula.

{% stepper %}
{% step %}

### When manual editing is available

Manual editing is available when:

* The variable is set to a manual or direct input mode.
* The series is not fully controlled by a custom formula or certain locked presets.
* The cells in the time series grid are shown as editable.

{% hint style="info" %}
If the grid is read only, you may need to switch the variable to a manual-based configuration first.
{% endhint %}
{% endstep %}

{% step %}

### Editing individual periods

To edit a single period:

* Open the **Variable Editor**.
* Click the cell for the period you want to change.
* Type a new value and press Enter.

The change is applied only to that period and will immediately flow into P\&L, Balance Sheet and Cashflow outputs.
{% endstep %}

{% step %}

### Editing ranges of periods

You can often edit ranges by:

* Copying a value and pasting it across several periods.
* Using a fill or drag mechanism if available.
* Pasting a block of values from an external spreadsheet.

This is useful for:

* Simple flat assumptions.
* Stepped patterns.
* Overriding imported or generated series for specific windows.
  {% endstep %}

{% step %}

### Interaction with presets and imports

Manual editing interacts with other logic as follows:

* **Custom formulas**: normally take full control of the series. You cannot manually edit individual periods while a formula is active.
* **Presets**: some presets allow local overrides; others do not. The editor will indicate whether manual cells are unlocked.
* **Imports**: historical periods may be read only if they are tied to accounting imports. Future periods may remain editable for forecast adjustments.

{% hint style="warning" %}
If you need fine control, consider switching to a manual mode or combining manual edits with drivers, rather than relying on heavy formulas.
{% endhint %}
{% endstep %}

{% step %}

### Keeping manual edits traceable

Because manual edits can be very localised:

* Use notes to explain major overrides or adjustments.
* Tag variables that contain significant manual shaping so they are easy to review.
* Periodically compare manual series against imported or driver-based baselines to ensure they still make sense.

This prevents silent divergence from the original logic.
{% endstep %}
{% endstepper %}

***

## Related articles

* [Importing Series](/syntax/variables-syntax/importing-series.md)
* [Selecting Series for Charts](/syntax/chart-and-table-syntax/selecting-series-for-charts.md)
* [Authentication (OAuth)](/help/xero-integration/authentication-oauth.md)
* [Build a Multi Scenario Comparison](/how-tos/scenarios-and-planning/build-a-multi-scenario-comparison.md)