diff --git a/dist/stomp.js b/dist/stomp.js
index 2e3afb3..1b0d04c 100644
--- a/dist/stomp.js
+++ b/dist/stomp.js
@@ -1,4 +1,4 @@
-// Generated by CoffeeScript 1.4.0
+// Generated by CoffeeScript 1.6.3
 (function() {
   var Byte, Client, Frame, Stomp,
     __hasProp = {}.hasOwnProperty;
@@ -9,7 +9,6 @@
   };
 
   Frame = (function() {
-
     function Frame(command, headers, body) {
       this.command = command;
       this.headers = headers != null ? headers : {};
@@ -92,7 +91,6 @@
   })();
 
   Client = (function() {
-
     function Client(ws) {
       this.ws = ws;
       this.ws.binaryType = "arraybuffer";
@@ -102,6 +100,7 @@
         outgoing: 10000,
         incoming: 10000
       };
+      this.heartbeatWindow = 0.10;
       this.subscriptions = {};
     }
 
@@ -132,6 +131,7 @@
       })(), serverOutgoing = _ref1[0], serverIncoming = _ref1[1];
       if (!(this.heartbeat.outgoing === 0 || serverIncoming === 0)) {
         ttl = Math.max(this.heartbeat.outgoing, serverIncoming);
+        ttl = ttl - (ttl * this.heartbeatWindow);
         if (typeof this.debug === "function") {
           this.debug("send PING every " + ttl + "ms");
         }
@@ -142,6 +142,7 @@
       }
       if (!(this.heartbeat.incoming === 0 || serverOutgoing === 0)) {
         ttl = Math.max(this.heartbeat.incoming, serverOutgoing);
+        ttl = ttl + (ttl * this.heartbeatWindow);
         if (typeof this.debug === "function") {
           this.debug("check PONG every " + ttl + "ms");
         }
diff --git a/src/stomp.coffee b/src/stomp.coffee
index 7408f23..59c7e7d 100644
--- a/src/stomp.coffee
+++ b/src/stomp.coffee
@@ -111,6 +111,9 @@ class Client
       # (value in ms)
       incoming: 10000
     }
+    # Send pings 10% faster and allow pongs 10% slower to account for
+    # inaccurate timing in the web browser
+    @heartbeatWindow = 0.10 #10%
     # subscription callbacks indexed by subscriber's ID
     @subscriptions = {}
 
@@ -129,6 +132,7 @@ class Client
 
     unless @heartbeat.outgoing == 0 or serverIncoming == 0
       ttl = Math.max(@heartbeat.outgoing, serverIncoming)
+      ttl = ttl - (ttl * @heartbeatWindow);
       @debug? "send PING every #{ttl}ms"
       @pinger = window?.setInterval(=>
         @ws.send Byte.LF
@@ -137,6 +141,7 @@ class Client
 
     unless @heartbeat.incoming == 0 or serverOutgoing == 0
       ttl = Math.max(@heartbeat.incoming, serverOutgoing)
+      ttl = ttl + (ttl * @heartbeatWindow)
       @debug? "check PONG every #{ttl}ms"
       @ponger = window?.setInterval(=>
         delta = Date.now() - @serverActivity
@@ -355,4 +360,4 @@ else if exports?
   Stomp.WebSocketClass = require('./test/server.mock.js').StompServerMock
 # or in the current object (e.g. a WebWorker)
 else
-  self.Stomp = Stomp
\ No newline at end of file
+  self.Stomp = Stomp