Formula Fields can be complicated sometimes. So, here are examples that will help you understand the usage of these types of fields in Zoho CRM.

1. IF ELSE Statement Example: If field name contains 'Golf Only 1 Meal', then return 265 ; Else if field name .contains 'Golf Only 2 Meals' return 295 else if field name contains 'Single Occ' return 665 or return 0
   Formula: If(Contains(${Contacts.fieldname}, 'Golf Only 1 Meal'),265,If(Contains(${Contacts.fieldname},'Golf Only 2 Meals'),295,If(Contains(${Contacts.fieldname},'Single Occ'),665,0 ) ) )
2. Example: 
   A manually entered Level; say A,B,C
   A manually entered File Received Date (Start Date)
   A formula field, that calculates a deadline date, based on the level and the File Received Date fields. This is called ''due date''.
   The calculation for Due Date -
   • If ''Level'' = A then the ''Due Date'' = ''File Received Date'' + 14 days
   • If ''Level'' = B then the ''Due Date'' = ''File Received Date'' + 10 days
   • If ''Level'' = C then the ''Due Date'' = ''File Received Date'' + 5 days
   Formula: If(Contains(${Leads.level},'A'),Adddate(${Leads.Start Date},14,'DAY'),If(Contains(${Leads.level},'B'),Adddate(${Leads.Start Date},10,'DAY'),If(Contains(${Leads.level},'C'),Adddate(${Leads.Start Date},5,'DAY'),Now())))
3. Example: To calculate the age based on the Date of Birth details.
   
   Formula:
   • Age in Years =
     Year(Now())-Year(${Leads.DOB})- If(Month(Now())*100+Dayofmonth(Now())>=Month(${Leads.DOB})*100+Dayofmonth(${Leads.DOB}) ,0 ,1 )
   • Age in Months = (Datecomp(Now(),${Leads.DOB}))/(60*24*30)
4. Create a matrix or a combination of two or three fields.
   Example: 
   A Product has number fields namely Style, Color and Size.
   Another field Product Matrix, should give the output as a combination of Style, Color and Size values.
   
   Formula: 
   Concat(Tostring(${Products.Style}),Tostring(${Products.Colour}),Tostring(${Products.Size}))
   Return Type: String
5. Change the return type of the drop-down value as a number and calculate the values of two or more drop-down fields.
   Note that the drop-down values are considered as string values, and not number values.
   
   Example: 
   Drop-down 1 Values - 10, 20, 30
   Drop-down 2 Values - 5, 10, 15
   Formula (number) field needs to calculate - (Drop-down 1*Drop-down 2)+Drop-down 2
   
   Formula: 
   (Tonumber(Drop-down 1)*Tonumber(Drop-down 2))+Tonumber(Drop-down 2)
   Return Type: Number