diff --git a/src/components/fileviewercov.js b/src/components/fileviewercov.js
index 4c3a1ff..1319611 100644
--- a/src/components/fileviewercov.js
+++ b/src/components/fileviewercov.js
@@ -91,17 +91,15 @@ const Test = ({ row, test, expand, handleTestOnExpand }) => (
 
 // shows coverage percentage of a file
 export const CoveragePercentageViewer = ({ coverage }) => {
-  const coveredLines = coverage.coveredLines.length;
-  const totalLines = coveredLines + coverage.uncoveredLines.length;
   let percentageCovered;
-  if (coveredLines !== 0 || coverage.uncoveredLines.length !== 0) {
+  if (coverage.percentage) {
     percentageCovered = (
       <div
         className="coverage-percentage"
-        style={{ backgroundColor: `${getPercentCovColor(coveredLines / totalLines)}` }}
+        style={{ backgroundColor: `${getPercentCovColor(coverage.percentage)}` }}
       >
-        {((coveredLines / totalLines) * 100).toPrecision(4)}
-        % - {coveredLines} lines covered out of {totalLines} coverable lines
+        {coverage.percentage.toPrecision(4)}
+        % - {coverage.numCovLines} lines covered out of {coverage.numTotalLines} coverable lines
       </div>
     );
   } else {
diff --git a/src/utils/color.js b/src/utils/color.js
index 0ec5d4b..8e8e645 100644
--- a/src/utils/color.js
+++ b/src/utils/color.js
@@ -2,6 +2,6 @@ import * as Chroma from 'chroma-js';
 
 const getPercentCovColor = percent =>
   // warm red, lemon yellow, neon green
-  Chroma.scale(['#ff4f5e', '#fff44f', '#54ffbd']).mode('lab')(percent);
+  Chroma.scale(['#ff4f5e', '#fff44f', '#54ffbd']).mode('lab')(percent / 100);
 
 export default getPercentCovColor;
diff --git a/src/utils/data.js b/src/utils/data.js
index 126e100..6010d69 100644
--- a/src/utils/data.js
+++ b/src/utils/data.js
@@ -63,6 +63,12 @@ export const fileRevisionCoverageSummary = (coverage) => {
     });
   });
   s.uncoveredLines = _.uniq(s.uncoveredLines);
+  // calculate line coverage stats
+  s.numCovLines = s.coveredLines.length;
+  s.numUncovLines = s.uncoveredLines.length;
+  s.numTotalLines = s.numCovLines + s.numUncovLines;
+  s.percentage = (s.numCovLines !== 0 ||
+     s.numUncovLines !== 0) ? ((s.numCovLines / s.numTotalLines) * 100) : undefined;
   return s;
 };