Carry out the following steps to create an account Credit Score formula field that uses the data contained in a custom field to display a Google Chart graphic:

1. Click on the Setup gear icon in the top right-hand of the main Home page, as shown in the following screenshot:

2. Click the Setup option, as shown in the following screenshot:

3. Navigate to the Account customization setup page, by clicking the following: Objects and Fields | Object Manager | Account | Fields and Relationships.
4. Locate the Fields & Relationships section on the right of the page.
5. Click New.

We are presented with the Step 1. Choose the field type page.

6. Select the Formula option.
7. Click Next.

We are presented with the Step 2. Choose output type page.

8. Type Credit Score Graphic in the Field Label textbox.
9. Click on the Field Name. When clicking out of the Field Label textbox, the Field Name is automatically filled with the value Credit_Score_Graphic.
10. Set the Formula Return Type as Text.
11. Click Next.

We are presented with the Step 3. Enter formula page.

12. Paste the following code in the formula edit box (as shown in the next screenshot):

 
/*********************************************************** 

Google Chart type Google-O-meter 

  
***********************************************************/ 
IF( 
  ISNUMBER( TEXT(Credit_Score__c) ),  
    IMAGE(  
      "http://chart.apis.google.com/chart?cht=gm" & 
      "&chxl=0:|0|50|100&chxt=y&chs=200x120&chls=2|10" &  
      "&chd=t:" & TEXT((Credit_Score__c)) & 
      "&chl=" & TEXT(Credit_Score__c), "Credit Score Graphic" 
    ), 
  "Not Specified" 
)

13. In the Blank Field Handling section, select the option Treat blank fields as blanks, as shown in the following screenshot:

14. Optionally, enter a value in the Description field.
15. Optionally, enter a value in the Help Text field.
16. Click Next.

We will be presented with the Step 4. Establish field-level security page.

17. Select the profiles to which you want to grant edit access to this field via the field-level security. The field will be hidden from all profiles if you do not add it to the field-level security.
18. Click Next.

We will be presented with the Step 5. Add to page layouts page.

19. Select the page layouts that should include this field. The field will be added as the last field in the first two-column section of these page layouts. The field will not appear on any pages if you do not select a layout.
20. Finally, click Save.