diff --git a/src/app/pdf/[id]/page.tsx b/src/app/pdf/[id]/page.tsx
index 9deec96..f9df8ca 100644
--- a/src/app/pdf/[id]/page.tsx
+++ b/src/app/pdf/[id]/page.tsx
@@ -25,6 +25,7 @@ export default function PDFViewerPage() {
   const [document, setDocument] = useState<{ name: string; data: Blob } | null>(null);
   const [error, setError] = useState<string | null>(null);
   const [isLoading, setIsLoading] = useState(true);
+  const [zoomLevel, setZoomLevel] = useState<number>(100);
 
   useEffect(() => {
     async function loadDocument() {
@@ -46,6 +47,9 @@ export default function PDFViewerPage() {
     loadDocument();
   }, [id, getDocument]);
 
+  const handleZoomIn = () => setZoomLevel(prev => Math.min(prev + 10, 200));
+  const handleZoomOut = () => setZoomLevel(prev => Math.max(prev - 10, 50));
+
   if (error) {
     return (
       <div className="flex flex-col items-center justify-center min-h-screen">
@@ -71,20 +75,39 @@ export default function PDFViewerPage() {
     <>
       <TTSPlayer />
       <div className="p-2 pb-2 border-b border-offbase">
-        <div className="flex items-center justify-between">
-          <Link
-            href="/"
-            onClick={() => {
-              setText('');
-              stop();
-            }}
-            className="inline-flex items-center px-3 py-1 bg-base text-foreground rounded-lg hover:bg-offbase transition-colors"
-          >
-            <svg className="w-4 h-4 mr-2 text-muted" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth="2" d="M10 19l-7-7m0 0l7-7m-7 7h18" />
-            </svg>
-            Documents
-          </Link>
+        <div className="flex flex-wrap items-center justify-between">
+          <div className="flex items-center gap-4">
+            <Link
+              href="/"
+              onClick={() => {
+                setText('');
+                stop();
+              }}
+              className="inline-flex items-center px-3 py-1 bg-base text-foreground rounded-lg hover:bg-offbase transition-colors"
+            >
+              <svg className="w-4 h-4 mr-2 text-muted" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path strokeLinecap="round" strokeLinejoin="round" strokeWidth="2" d="M10 19l-7-7m0 0l7-7m-7 7h18" />
+              </svg>
+              Documents
+            </Link>
+            <div className="bg-offbase px-2 py-0.5 rounded-full flex items-center gap-2">
+              <button
+                onClick={handleZoomOut}
+                className="text-xs hover:text-accent transition-colors"
+                aria-label="Zoom out"
+              >
+                －
+              </button>
+              <span className="text-xs">{zoomLevel}%</span>
+              <button
+                onClick={handleZoomIn}
+                className="text-xs hover:text-accent transition-colors"
+                aria-label="Zoom in"
+              >
+                ＋
+              </button>
+            </div>
+          </div>
           <h1 className="mr-2 text-md font-semibold text-foreground">
             {isLoading ? 'Loading...' : document?.name}
           </h1>
@@ -95,7 +118,7 @@ export default function PDFViewerPage() {
           <PDFSkeleton />
         </div>
       ) : (
-        <PDFViewer pdfData={document?.data} />
+        <PDFViewer pdfData={document?.data} zoomLevel={zoomLevel} />
       )}
     </>
   );
diff --git a/src/components/PDFViewer.tsx b/src/components/PDFViewer.tsx
index 48fb198..642d81e 100644
--- a/src/components/PDFViewer.tsx
+++ b/src/components/PDFViewer.tsx
@@ -11,10 +11,12 @@ import { usePDF } from '@/contexts/PDFContext';
 
 interface PDFViewerProps {
   pdfData: Blob | undefined;
+  zoomLevel: number;
 }
 
-export function PDFViewer({ pdfData }: PDFViewerProps) {
+export function PDFViewer({ pdfData, zoomLevel }: PDFViewerProps) {
   const [numPages, setNumPages] = useState<number>();
+  const [containerWidth, setContainerWidth] = useState<number>(0);
   const { setText, currentSentence, stopAndPlayFromIndex, isProcessing } = useTTS();
   const [pdfText, setPdfText] = useState('');
   const [pdfDataUrl, setPdfDataUrl] = useState<string>();
@@ -143,6 +145,29 @@ export function PDFViewer({ pdfData }: PDFViewerProps) {
     };
   }, [pdfText, currentSentence, highlightPattern, clearHighlights]);
 
+  // Add scale calculation function
+  const calculateScale = (pageWidth: number = 595) => {  // 595 is default PDF width in points
+    const margin = 24; // 24px padding on each side
+    const targetWidth = containerWidth - margin;
+    const baseScale = targetWidth / pageWidth;
+    return baseScale * (zoomLevel / 100);
+  };
+
+  // Add resize observer effect
+  useEffect(() => {
+    if (!containerRef.current) return;
+
+    const observer = new ResizeObserver(entries => {
+      const width = entries[0]?.contentRect.width;
+      if (width) {
+        setContainerWidth(width);
+      }
+    });
+
+    observer.observe(containerRef.current);
+    return () => observer.disconnect();
+  }, []);
+
   function onDocumentLoadSuccess({ numPages }: { numPages: number }): void {
     setNumPages(numPages);
   }
@@ -150,7 +175,7 @@ export function PDFViewer({ pdfData }: PDFViewerProps) {
   return (
     <div
       ref={containerRef}
-      className="flex flex-col items-center overflow-auto max-h-[calc(100vh-100px)]"
+      className="flex flex-col items-center overflow-auto max-h-[calc(100vh-100px)] w-full px-6"
       style={{ WebkitTapHighlightColor: 'transparent' }}
     >
       {loadingError ? (
@@ -161,7 +186,7 @@ export function PDFViewer({ pdfData }: PDFViewerProps) {
         noData={<PDFSkeleton />}
         file={pdfDataUrl}
         onLoadSuccess={onDocumentLoadSuccess}
-        className="flex flex-col items-center"
+        className="flex flex-col items-center m-0" 
       >
         {Array.from(
           new Array(numPages),
@@ -178,7 +203,7 @@ export function PDFViewer({ pdfData }: PDFViewerProps) {
                   renderAnnotationLayer={true}
                   renderTextLayer={true}
                   className="shadow-lg"
-                  scale={1.2}
+                  scale={calculateScale()}
                 />
               </div>
             </div>
diff --git a/src/contexts/TTSContext.tsx b/src/contexts/TTSContext.tsx
index 3164645..3dee2b6 100644
--- a/src/contexts/TTSContext.tsx
+++ b/src/contexts/TTSContext.tsx
@@ -131,7 +131,7 @@ export function TTSProvider({ children }: { children: React.ReactNode }) {
   }, [audioContext]);
 
   // Text preprocessing function to clean and normalize text
-  const preprocessText = (text: string): string => {
+  const preprocessSentenceForAudio = (text: string): string => {
     return text
       // Replace URLs with descriptive text including domain
       .replace(/\S*(?:https?:\/\/|www\.)([^\/\s]+)(?:\/\S*)?/gi, '- (link to $1) -')
@@ -147,7 +147,7 @@ export function TTSProvider({ children }: { children: React.ReactNode }) {
 
   const splitIntoSentences = (text: string): string[] => {
     // Preprocess the text before splitting into sentences
-    const cleanedText = preprocessText(text);
+    const cleanedText = preprocessSentenceForAudio(text);
     const doc = nlp(cleanedText);
     return doc.sentences().out('array') as string[];
   };
@@ -173,7 +173,7 @@ export function TTSProvider({ children }: { children: React.ReactNode }) {
 
     try {
       // Only set processing if we need to fetch from API
-      const cleanedSentence = preprocessText(sentence);
+      const cleanedSentence = preprocessSentenceForAudio(sentence);
       if (!audioCacheRef.current.has(cleanedSentence)) {
         setIsProcessing(true);
       }