diff --git a/tools/covhtml.js b/tools/covhtml.js
new file mode 100644
index 0000000000..cb262d8b4f
--- /dev/null
+++ b/tools/covhtml.js
@@ -0,0 +1,60 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// This tool is to make pretty HTML from --cov output.
+
+var fs = require('fs');
+var path = require('path');
+
+var jsonFilename = process.argv[2];
+if (!jsonFilename) {
+  console.error("covhtml.js node-cov.json > out.html");
+  process.exit(1);
+}
+
+var jsonFile = fs.readFileSync(jsonFilename);
+var cov = JSON.parse(jsonFile);
+
+var out = '<html><style>pre { margin: 0; padding: 0; } </style><body>';
+
+for (var fn in cov) {
+  var source = fs.readFileSync(fn, 'utf8');
+  var lines = source.split('\n');
+
+  out += '<h2>' + path.basename(fn) + '</h2>\n<div>\n';
+
+  for (var i = 0; i < lines.length; i++) {
+    lines[i] = lines[i].replace('<', '&lt;');
+    lines[i] = lines[i].replace('>', '&gt;');
+    if (cov[fn][i]) {
+      out += '<pre>'
+    } else {
+      out += '<pre style="background: #faa">'
+    }
+    out += lines[i] + '</pre>\n';
+  }
+
+  out += '</div>\n';
+}
+
+out += '</body></html>'
+
+console.log(out);
