# Formula field
Formulas let you transform and combine existing fields into a new Formula field. For example, you can:
* Concatenate `First name` and `Last name` fields into a `Full name` Formula field.
* Multiply `Price` and `Units` field to get the result in the `Revenue` Formula field.
The field will show only in your Stacker app, and won't show up in your Airtable base.
## Create a formula field
1. Go to **Manage Fields and data**
2. Select the table and select **Fields**
3. Click **Add field**
4. Give your field a name
5. Select the field type: **Formula**
6. Type in your formula and click **Save**
## 
## Fields in formulas
To use a field in a formula, the field needs to be in the table where you're creating the formula field. It also needs to be one of the following data types:
* Text
* Long Text
* Number
* Checkbox
* URL
* Single Select Dropdown
* Percentage
* Currency
* Rich Text
* Date
* Date and Time
* Multiple Select Dropdown
To use a field in a formula, you will need to wrap it in curly brackets. For example, {Price}. If you type in the opening curly bracket, we will suggest all available fields.
## List of formulas
Functions work with any [valid field data types](#h_01FZGB5YYAD3T8S4JEEHNZXE4Q), while operators work only on number fields. If you use an operator for a non-number field, we will try to convert it into a number. If we can't, you'll see an error message.
#### SUM
Returns the sum of two or more numbers.
**Example:**
`SUM({Sold},{Not sold})`
or
`{Sold} + {Not sold}`
####
#### SUBTRACT
Returns the difference of two numbers.
**Example:**
`{Total stock} - {Sold stock}`
####
#### MULTIPLY
Returns the product of two numbers.
**Example:**
`{Sold} * {Price}`
####
#### DIVIDE
Returns one number divided by another.
**Example:**
`{Total sold} / {Price}`
####
#### AVERAGE
Returns the average of the values in two or more fields.
**Example:**
`AVERAGE({Sold},{Not sold})`
####
#### NOT EQUAL TO
Check if one value is not equal to another.
**Example:**
`1!=2 =>True` (represented as a checked checkbox)
####
#### EQUAL TO
Compare if one value is equal to another value.
**Example:**
`1=1 =>True` (represented as an empty checkbox)
####
#### GREATER THAN
Compare if one value is greater than another value.
**Example:**
`1>5 =>False` (represented as an empty checkbox)
####
#### GREATER THAN OR EQUAL TO
Compare if one value is greater than or equal to another value.
**Example:**
`2>=2 =>True` (represented as a checked checkbox)
####
#### LESS THAN
Compare if one value is less than another value.
**Example:**
`5<1 =>False` (represented as an empty checkbox)
####
#### LESS THAN OR EQUAL TO
Compare if one value is less than another value.
**Example:**
`2<=2 =>True` (represented as a checked checkbox)
####
#### CONCAT( , ) or &
Concatenate two values.
**Example:**
`CONCAT("Hello ", {Fullname}, " !")`
or
`"Hello " & {Fullname} & " !"`
####
#### IF (statement, Action A, Action B)
Check whether the statement is true. If it is true, then do action A, if it is false do action B.
**Example:**
`IF({UserId}, "https://dashboard.com/" + {UserId}, "")`
####
#### AND( )
Returns true if all the arguments are true, returns false otherwise.
**Example:**
`AND({Field 1}),{Field 2})`
or
`{Field 1} AND {Field 2}`
####
#### OR( )
Returns true id any one of the argument is true.
**Example:**
`OR({Field 1}),{Field 2})`
or
`{Field 1} OR {Field 2}`
####
#### NOT( )
Reverse a true to false.
**Example:**
`NOT(a=b`
####
#### LEN
Returns the length of a string.
**Example:**
`LEN("Hello World") =>11`
####
#### REGEX\_MATCH( )
Returns whether the input text matches a regular expression.
**Example:**
`REGEX_MATCH("Good Morning","Good.Morning" =>True` (Represented as a checked checkbox)
####
#### REGEX\_REPLACE( )
Substitutes all matching substrings with a replacement string value.
**Example:**
`REGEX_REPLACE("Good Morning","M*",""=>"Good"`
####
#### REGEX\_EXTRACT( )
Returns the first substring that matches a regular expression.
**Example:**
`REGEX_EXTRACT("Good Morning","M*",""=>"Morning"`
####
#### TRIM( )
Removes the whitespace at the beginning and end of string.
**Example:**
`TRIM(" Hello ") =>"Hello"`
####
#### UPPER( )
Makes string uppercase.
**Example:**
`UPPER("Hello") =>"HELLO"`
####
#### LOWER( )
Makes string lowercase.
**Example:**
`LOWER("Hello") =>"hello"`
####
#### RIGHT( )
Extract how many characters from the end of the string. Accepts string for first arg, number for second.
**Example:**
`RIGHT("Hello",2) =>"lo"`
####
#### IS\_SAME( )
Compares two dates up to a unit and determines whether they are identical. Returns true or false.
**Example:**
`IS_SAME({date 1},{date 2}, 'unit')`
current acceptable units are:
`'exact'`(matches all units)
`'year'`, `'month'`, `'day'`
####
#### IS\_BEFORE( )
Determines if \[date1] is earlier than \[date2]. Returns 1 is yes, 0 if no.
**Example:**
`IS_BEFORE({date 1},{date 2})`
####
#### IS\_AFTER( )
Determines if \[date1] is later than \[date2]. Returns 1 is yes, 0 if no.
**Example:**
`IS_AFTER({date 1},{date 2})`
####
#### YEAR( )
Returns the four-digit year of datetime.
**Example:**
`YEAR({Date},[timezone])`
####
#### MONTH( )
Returns the month of a datetime as a number between 1 (January) and 12 (Decemeber).
**Example:**
`MONTH({Date},[timezone])`
####
#### DAY( )
Returns the day of a month of a datetimein the form of a number between 1-31.
**Example:**
`DAY({Date},[timezone])`
####
#### HOUR( )
Returns the hour of a datetime as a number between 0 (12.00am) and 23 (11.00pm).
**Example:**
`HOUR({Date},[timezone])`
####
#### MINUTE( )
Returns the minute if datetime as a number.
**Example:**
`MINUTE({Date},[timezone])`
####
#### LEFT( )
Extract how many characters from the beginning of the string. Accepts the string for first arg, number for second.
**Example:**
`LEFT("Hello",2) =>"He"`
####
#### DATEDIF( )
Returns the difference between datetimes in the unit specified.
Unit accepts:
`'year'`,`'month'`,`'week'`,`'day'`,`'hour'`,`'minute'`
**Example:**
`DATEDIF([date1],[date2],"units")`
####
#### MIN( )
Returns the item with the lowest value.
**Example:**
`MIN(number 1, number 2, number 3...)`
####
#### MAX( )
Returns the largest item between two or more parameters.
**Example:**
`MAX(number 1, number 2, number 3...)`
####
#### ABS(number)
Returns the absolute value.
**Example:**
`ABS(-5)`
####
#### DATEADD( )
Adds a time/date interval to a date and then returns the date.
**Example:**
`DATEADD([date],[#],"units")` (accepts years, months, weeks and days as well as singular counter-parts)
####
#### TODAY(timezone)
Returns the current date, but not the current time.
####
#### NOW( )
Returns the current date and time.
####
#### ROUND( )
Rounds to a number of decimal places as specified by precision e.g "0", "1", etc.
**Example:**
`ROUND({Unit Price},0)`
#### ROUNDUP( )
Rounds the value to the number of decimal places given by "precision" always rounding up. e.g "0", "1", etc.
**Example:**
`ROUNDUP({Unit Price},0)`
####
#### VALUE(string)
Coverts text string to a number.
**Example:**
`VALUE({Quoted Price})`
####
#### INT( )
Returns the greatest integer that is less than or equal to the number.
**Example:**
`INT({Unit Price})`
## Error messages
If a formula is invalid, you will see an error message that might help you understand what went wrong.
| Error | Meaning |
| ------------------------------------------------------------------------- | ------------------------------------------------------------------------------ |
| `Missing formula function` or `Unexpected formula function` | Means that you were very creative, but we don't have the formula function yet. |
| `Function only works with field_type but field is a another_field_type` | Shows when using a field with an incompatible field type. |
| `In an IF function, field_name and field_name_2 must be of similar types` | Shows in an IF function when the Action A and Action B are different types. |
| `Missing keys in formula 'IF' function: else` | Means that there is a missing else (Action B) in the IF function. |