diff --git a/generators/dart/colour.js b/generators/dart/colour.js
index 7ded91419..105608988 100644
--- a/generators/dart/colour.js
+++ b/generators/dart/colour.js
@@ -69,15 +69,15 @@ Blockly.Dart['colour_rgb'] = function(block) {
       'colour_rgb',
       ['String ' + Blockly.Dart.FUNCTION_NAME_PLACEHOLDER_ +
           '(num r, num g, num b) {',
-       '  num rn = (Math.max(Math.min(r, 1), 0) * 255).round();',
+       '  num rn = (Math.max(Math.min(r, 100), 0) * 2.55).round();',
        '  String rs = rn.toInt().toRadixString(16);',
        '  rs = \'0$rs\';',
        '  rs = rs.substring(rs.length - 2);',
-       '  num gn = (Math.max(Math.min(g, 1), 0) * 255).round();',
+       '  num gn = (Math.max(Math.min(g, 100), 0) * 2.55).round();',
        '  String gs = gn.toInt().toRadixString(16);',
        '  gs = \'0$gs\';',
        '  gs = gs.substring(gs.length - 2);',
-       '  num bn = (Math.max(Math.min(b, 1), 0) * 255).round();',
+       '  num bn = (Math.max(Math.min(b, 100), 0) * 2.55).round();',
        '  String bs = bn.toInt().toRadixString(16);',
        '  bs = \'0$bs\';',
        '  bs = bs.substring(bs.length - 2);',