Google Sheets – Conditional Formatting Based on Another Cell

Complex conditional formatting can be achieved in Google Spreadsheets using Google Apps Script. For example, you could write a function that changes the background colour of an entire row based on the value in one of its cells, something that I do not think is possible with the "Change color with rules" menu. You would probably want to set triggers for this function such as "On Edit", "On Open" and "On Form Submit".

Documentation for setBackgroundRGB() function

UPDATE: Here is a Google Apps Script example of changing the background color of an entire row based on the value in column A. If the value is positive, use green. If empty, white. Otherwise, red. See the results in this public Google Spreadsheet. (You will have to be signed in for the script to run, but without signing in you can still see results).

function colorAll() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var startRow = 2;
  var endRow = sheet.getLastRow();

  for (var r = startRow; r <= endRow; r++) {
    colorRow(r);
  }
}

function colorRow(r){
  var sheet = SpreadsheetApp.getActiveSheet();
  var dataRange = sheet.getRange(r, 1, 1, 3);

  var data = dataRange.getValues();
  var row = data[0];

  if(row[0] === ""){
    dataRange.setBackgroundRGB(255, 255, 255);
  }else if(row[0] > 0){
    dataRange.setBackgroundRGB(192, 255, 192);
  }else{
    dataRange.setBackgroundRGB(255, 192, 192);
  }

  SpreadsheetApp.flush(); 
}

function onEdit(event)
{
  var r = event.source.getActiveRange().getRowIndex();
  if (r >= 2) {
    colorRow(r);
  }
}

function onOpen(){
  colorAll();
}

​

Here is what you can do:

1. RightClick B2 → select Conditional formatting → select Custom Formula is (from the List)
2. Enter the following formula in the textbox: =b2>=c2
3. Check the Background Color and select green color
4. Click on Add another rule
5. Select Custom Formula is (from the List)
6. Enter the following formula in the textbox: =b2<c2
7. Check the Background Color and select red color
8. Click on Save Rules
9. Highlight B2 and click on Paint Format option on the tool bar.
10. Now click on cell B3 and drag until cell - B117 (this should apply the conditional formatting on cell ranging from B3-B117)

And for your second condition (i.e., to highlight D with green if it is greater than or equal to E, red if it is less than E) - simply repeat the above steps by interchanging D2 for B2 and E2 for C2.