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# Calcuation

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The [**Calculation field**](https://formester.com/features/calculating-fields/) in Formester allows you to perform custom math operations inside your form. You can add numeric fields (like number inputs, price, or quantity) and then use formulas to calculate totals, scores, or other values. This is perfect for **order forms, quizzes, and estimators**.

# Adding a Calculation Field
* Open your form in the **Formester editor**.
* Click **Add Elements**.
* Scroll to **Others** and select **Calculation**.
* A new calculation field will appear on your form.

### Setting Up a Formula
* Click on the **Calculation field** to open the **Properties panel**.
* In the formula editor, type your expression.
* Use the **@ sign** to recall any numeric field from your form.
Example:
If your form has a field for *Quantity* and a field for *Price*, you can write:
```
@Quantity * @Price
```
This will automatically calculate the total.

### Supported Operations
You can use:
* **Addition (+)** → `@Field1 + @Field2`
* **Subtraction (-)** → `@Field1 - @Field2`
* **Multiplication (*)** → `@Field1 * @Field2`
* **Division (/)** → `@Field1 / @Field2`
* **Parentheses** for order of operations → `(@Field1 + @Field2) * @Field3`

### Using Default Values
* You can assign a **default value** to numeric fields.
* When recalled with `@`, the formula will automatically include them.
Example: A tax rate field with default value `0.18` can be included in your calculation.

### Displaying the Result
* You can rename the **Calculation field label** to match your use case.
* Example: *“Order Total”*, *“Final Score”*, *“Estimated Cost”*.
* The result updates automatically as users change input values.

### Use Cases
* **Order Forms**: Calculate product totals with quantity and price.
* **Quizzes**: Add scores automatically based on user answers.
* **Cost Estimators**: Estimate pricing for services based on user selections.
* **Surveys**: Sum up numeric ratings to give a total satisfaction score.

### Publish and Test
* Click **Publish** once your formula is ready.
* Preview your form and test different inputs to confirm your calculations are correct.