diff --git a/src/paste-markdown-link.ts b/src/paste-markdown-link.ts
index 1c9674d..34111ee 100644
--- a/src/paste-markdown-link.ts
+++ b/src/paste-markdown-link.ts
@@ -55,6 +55,7 @@ function linkify(selectedText: string, text: string): string {
   return `[${selectedText}](${text})`
 }
 
+const URL_REGEX = /https?:\/\/(www\.)?[-a-zA-Z0-9@:%._+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\/?\s*?$/i
 function isURL(url: string): boolean {
-  return /^https?:\/\//i.test(url)
+  return URL_REGEX.test(url)
 }
diff --git a/test/test.js b/test/test.js
index b88f5e0..f5c74f8 100644
--- a/test/test.js
+++ b/test/test.js
@@ -43,6 +43,14 @@ describe('paste-markdown', function () {
       assert.equal(textarea.value, 'The examples can be found [here](https://github.com).')
     })
 
+    it('creates a markdown link when the pasted url includes a trailing slash', function () {
+      // eslint-disable-next-line i18n-text/no-en
+      textarea.value = 'The examples can be found here.'
+      textarea.setSelectionRange(26, 30)
+      paste(textarea, {'text/plain': 'https://www.github.com/'})
+      assert.equal(textarea.value, 'The examples can be found [here](https://www.github.com/).')
+    })
+
     it("doesn't paste a markdown URL when pasting over a selected URL", function () {
       // eslint-disable-next-line i18n-text/no-en
       textarea.value = 'The examples can be found here: https://docs.github.com'
@@ -66,6 +74,15 @@ describe('paste-markdown', function () {
       assert.equal(textarea.value, '@')
     })
 
+    it("doesn't paste markdown URL when additional text is being copied", function () {
+      textarea.value = 'github'
+      textarea.setSelectionRange(0, 6)
+      paste(textarea, {'text/plain': 'https://github.com plus some other content'})
+      // Synthetic paste events don't manipulate the DOM. The same textarea value
+      // means that the event handler didn't fire and normal paste happened.
+      assert.equal(textarea.value, 'github')
+    })
+
     it('turns html tables into markdown', function () {
       const data = {
         'text/html': tableHtml