diff --git a/bg/monitor.js b/bg/monitor.js
index 6fd4a7b..a1c1c9f 100644
--- a/bg/monitor.js
+++ b/bg/monitor.js
@@ -16,6 +16,7 @@ browser.storage.onChanged.addListener((changes, area) => {
 		options[key] = changes[key].newValue
 	    }
 	}
+	updateTimer()
     }
 })
 
@@ -63,14 +64,22 @@ function checkClipboard() {
 }
 
 function updateTimer() {
+    function stop() {
+	clearInterval(timer.id)
+	timer = null
+    }
+    function start() {
+	const id = setInterval(checkClipboard, options.monitorInterval)
+	timer = { id, interval: options.monitorInterval }
+    }
     if(listeningTabs.length > 0) {
 	if(timer === null) {
-	    const id = setInterval(checkClipboard, 1000)
-	    timer = { id }
+	    start()
+	} else if(timer.interval !== options.monitorInterval) {
+	    stop()
+	    start()
 	}
     } else {
-	if(timer !== null) {
-	    clearInterval(timer.id)
-	}
+	stop()
     }
 }
diff --git a/default-options.js b/default-options.js
index 6190c42..90584c4 100644
--- a/default-options.js
+++ b/default-options.js
@@ -1,4 +1,5 @@
 const defaultOptions = {
     elemName: 'p',
-    containerSelector: 'body'
+    containerSelector: 'body',
+    monitorInterval: 300
 }
diff --git a/options.html b/options.html
index 376d64f..e5cb3a9 100644
--- a/options.html
+++ b/options.html
@@ -16,6 +16,10 @@
 	  <label for="container-selector">Container selector </label>
 	  <input id="container-selector" type="text"/>
 	</div>
+	<div class="pure-control-group">
+	  <label for="monitor-interval">Timer interval </label>
+	  <input id="monitor-interval" type="number" min="100" step="10"/>
+	</div>
       </fieldset>
     </form>
   </body>
diff --git a/options.js b/options.js
index a271384..f8dcd68 100644
--- a/options.js
+++ b/options.js
@@ -1,13 +1,21 @@
 document.addEventListener("DOMContentLoaded", () => {
     const elemName = document.querySelector("#elem-name"),
-	  containerSelector = document.querySelector("#container-selector")
+	  containerSelector = document.querySelector("#container-selector"),
+	  monitorInterval = document.querySelector("#monitor-interval")
 
     const storage = browser.storage.local
     
     storage.get(defaultOptions).then(o => {
 	elemName.value = o.elemName
 	containerSelector.value = o.containerSelector
+	monitorInterval.value = o.monitorInterval
     })
     elemName.onchange = () => storage.set({ elemName: elemName.value })
     containerSelector.onchange = () => storage.set({ containerSelector: containerSelector.value })
+    monitorInterval.onchange = () => {
+	const newVal = monitorInterval.value
+	if(newVal >= 100) {
+	    storage.set({ monitorInterval: monitorInterval.value })
+	}
+    }
 })