---
title: "Best practices for writing formulas"
slug: "best-practices-writing-formulas"
updated: 2026-04-24T17:18:11Z
published: 2026-04-24T17:18:11Z
canonical: "help.quickbase.com/best-practices-writing-formulas"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.quickbase.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Best practices for writing formulas

## Get familiar with operator precedence

Quickbase acts on certain operators before it acts on others. This is called operator precedence. Operator precedence impacts the outcome of your formula.

- Quickbase reads operators in a predetermined order, not left to right
- You can change the order of operator evaluation by using parentheses
- Quickbase always starts reading a formula within the deepest set of parentheses
- Review [operator precedence](/v1/docs/operator-precedence-in-formulas)

## Add comments to formulas

Comments help you and others understand parts of your formula. Use double slashes (//) to include comments in your formula. Everything you type from the double slashes to the end of the line is a comment, not part of the formula.

Example of a formula with comments

```plaintext
If ( Abs([x]) < 5,        //test the value
    "Less than 5",         //return one result
    "Not less than 5"      //otherwise return another result
)
```

## Create formula variables

Formula variables can help you simplify complicated formulas. See [Formula variables](/v1/docs/formula-variables).

## Working with null values

Most fields can have a special value called the *null value*. Null means that a field's value is undefined, or that no data is entered in the field.

Things you should know:

- Checkbox and text fields are never null. A Boolean value is either true or false. For example, a checkbox field is either checked or unchecked.
- Empty text fields ("") are considered text strings with zero characters, not null values
- Not all functions can handle null values. For example, in the formula `[Field name]=null` the equals operator requires a value so this example doesn't work. The equals operator can handle a zero, but not a null value.

### Null is useful in formulas

For instance, if you want to get an invoice total only if the **Delivered on** field is filled out, create a formula in the **total** field that says: "If there's data in the **Delivered on** Date field, then add **subtotal** and **tax**.

Example of a formula with a null value

```plaintext
If(not IsNull([Delivered on]),[subtotal] + [tax],null)
```

This means that if the **Delivered on** date field contains a value, then take the value in the **subtotal** field and add it to the value in the **tax** field. Otherwise, leave the field empty (null).

### Few functions accept null as an argument

- `IsNull()` function returns True if the field is null and False if it's not
- `Nz()` function returns zero if the field is null; otherwise it returns the value of the field This is useful for calculations (see [Null formula examples](/v1/docs/best-practices-writing-formulas#null-formula-examples)) **Tip:** If you don't use the `Nz()` function, you can treat a null in a numeric field as a zero to use it in calculations. To set this up, [open the field's properties page](/v1/docs/change-the-properties-of-a-field-from-a-legacy-form) and turn on **Treat blank as zero in calculations** checkbox. For numeric fields, Quickbase turns this setting on automatically.

## Null formula examples

| YOU WANT TO | FORMULA | FORMULA EXPLANATION |
| --- | --- | --- |
| Get and display the value from the Temperature field. If the field is empty (null) use 98.6 instead | `If (IsNull([Temperature]), 98.6, [Temperature])` | If the **Temperature** field is null, then display the result **98.6**. Otherwise, display the value from the **Temperature** field. |
| Add the number of hours worked in a week | `Nz([Mon]) + Nz([Tues] + Nz([Wed]) + Nz([Thurs]) + Nz([Fri])` | - Return the value in the **Mon** field. - If the **Mon** field is null then return zero. Add that to the value in the **Tues** field. - If the **Tues** field is null then return zero. Add that to the value in the **Wed** field, and so on. **Note:** You'd use Nz() here instead of IsNull(). To add these values together, Quickbase needs the result to be a number. Nz() generates a zero for a null, which the program can use in the calculation. |
| Calculate the **Revenue** field if a date is entered in the **Submitted for Billing** field **Tip:** To return a result where a value is not null, add NOT in front of the IsNull() function | `If(not IsNull([Submitted for Billing]),[Revenue Forecast])` | If there's a value in the **Submitted for Billing** field, then display the value from the **Revenue Forecast** field |

**Note:** If a formula that includes a null function isn't working, access the field's properties page and turn off the **Treat blank as zero in calculations** checkbox.

## Requiring unique values in formula fields

- **Require unique values** in the formula field property page Unique values could be used to:
  - Create autonumbering
  - Concatenate multiple fields in a formula - text field to avoid duplicate records
- Formula fields that reference the following field types cannot be unique:
  - Lookup
  - Date/Time
  - Address
  - Record ID

## Up next

- [Commonly used formula functions and formula examples](/v1/docs/commonly-used-formula-functions-and-formula-examples)
- [Troubleshooting formulas](/v1/docs/troubleshooting-formulas)
-