> 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/how-input-fields-work/editing-bounds.md).

# Editing Bounds

This article explains how to edit bounds for input fields in Model Reef.

You will learn:

* What bounds are and where they apply.
* How to set minimum and maximum values.
* How bounds interact with validation and warnings.

Bounds help prevent errors by flagging values that fall outside expected ranges.

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### What bounds are

Bounds are optional limits attached to an input field, usually at the variable or driver level, such as:

* Minimum and maximum acceptable values.
* Typical ranges for growth rates, margins or utilisation.
* Thresholds for quantities like headcount or production volume.

They are not hard constraints on the model logic, but they provide warnings when inputs are outside the defined range.
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### Where to edit bounds

You edit bounds in the **Units and bounds panel**, accessed from:

* The Variable Editor.
* The Driver Editor for driver like assumptions.

For each relevant field or series you can set:

* Lower bound (minimum).
* Upper bound (maximum).

Bounds are defined in the same underlying units as the stored values.
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### How bounds affect input behaviour

When bounds are set:

* Values entered outside the bounds may trigger visual warnings.
* The system may request confirmation before accepting extreme values.
* In some configurations, values beyond bounds might be blocked, depending on how strict validation is configured.

Bounds do not change or clip values silently; they highlight potential issues for the modeller to address.
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### Choosing sensible bounds

To set useful bounds:

* Look at historical ranges for the variable or driver.
* Consider realistic business constraints (for example utilisation cannot exceed 100 percent).
* Set ranges wide enough to allow real variation but narrow enough to catch obvious mistakes.

Bounds can be adjusted over time as you learn more about the variable's behaviour.
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### Bounds and collaboration

Bounds are especially helpful when:

* Multiple Editors work on the same model.
* Viewers suggest input changes that are implemented by others.
* You hand off parts of the model to less experienced team members.

They serve as embedded modelling guidelines and reduce the risk of extreme assumptions creeping in unnoticed.
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### Reviewing bound warnings

When you see values flagged as outside bounds:

* Confirm whether the value is truly unusual or simply reflects a new reality.
* If the value is correct and likely to continue, update the bounds.
* If the value is a typo or misunderstanding, correct it.

Using bounds as a review tool improves model quality and oversight.
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## Related articles

* [Editing Frequency](/syntax/how-input-fields-work/editing-frequency.md)
* [Manual Time Series Editing](/syntax/variables-syntax/manual-time-series-editing.md)
* [Units & Bounds](/help/drivers-variables-and-timing/units-and-bounds.md)
* [Build a Financial Statements Reporting Suite](/how-tos/dashboards-and-reporting/build-a-financial-statements-reporting-suite.md)