> For the complete documentation index, see [llms.txt](https://devdocs.olisystems.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://devdocs.olisystems.com/kinetic-calculation-inputs.md).

# Kinetic calculation inputs

In addition to the mandatory inputs required for the various [flash calculations](/group1/api-functions.md), kinetic calculation inputs need to be specified in **params.kineticsParameters** if there are kinetic reactions defined in the chemistry model.

```javascript
{
    "params": {
        ...<snip>...
        "kineticsParameters": {
            "holdupTime": {
                "value": 100.0,
                "unit": "hr"
            },
            "numberSteps": {
                "value": 10,
                "unit": ""
            }
        }
    }
}
```

| params.kineticsParameters | type                                | description                                                                                                                       |
| ------------------------- | ----------------------------------- | --------------------------------------------------------------------------------------------------------------------------------- |
| holdupTime                | [valueObject](/terms-definition.md) | holdup time                                                                                                                       |
| numberSteps               | [valueObject](/terms-definition.md) | number of kinetics steps used in integrating kinetic rates, more steps lead to higher result accuracy and longer computation time |

### Survey Calculation

Survey calculation is supported for the variables below. Please refer to [Survey calculation](/survey-calculation.md) for explained input schema.

| supported **params.surveyInputs\[{}].field**   |
| ---------------------------------------------- |
| "/params/kineticsParameters/holdupTime/value"  |
| "/params/kineticsParameters/numberSteps/value" |