Although not visible on the surface, ConvertCalculator offers a lot of power when it comes to adding simple and more complex calculations. This article explains some of these calculations.

# How does a formula work?

Formulas are the most important feature in ConvertCalculator. A formula can consist of the following components:

- numbers, (
`1, 12, 1.5, 20.5`

) - operators (
`+, -, *, /, ^`

) - question values (QA, QB, QC)
- variable values (VA, VB, BC)
- datasheet values (DSA
*A, DSA*B)

The first two offer no explanation. Question values are the values users input themselves and are based on calculator questions. So if you ask for desired "width" or "finish", you can add values to these questions an d use them to calculate something (price, savings etc.).

Variables are a pro feature in ConvertCalculator. They are very similar to formulas. The only difference is that they can be re-used in formula's. With variables you can thus create re-usable calculations that you can use again in formula's.

An example of a simple formula is this:

```
QA * 100 + 100
```

In this formula we multiple the value of Question A by 100 and add 100. If a user changes the value of QA (for example by sliding the range slider), the value of the formula changes.

# Common issues

- Numbers with comma decimals (e.g
`1,1`

or`1,000.54`

) will NOT work. - Numbers with decimals without a leading zero (e.g
`.76`

) will NOT work. - Using
`=`

before a formula will cause the formula to throw an ERROR.