diff --git a/pom.xml b/pom.xml
index 862edde..0f65e90 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>me.indian.util</groupId>
     <artifactId>utils</artifactId>
-    <version>0.0.4.2</version>
+    <version>0.0.4.2.1</version>
 
     <properties>
         <maven.compiler.source>17</maven.compiler.source>
diff --git a/src/main/java/me/indian/util/Main.java b/src/main/java/me/indian/util/Main.java
index 454d086..d257930 100644
--- a/src/main/java/me/indian/util/Main.java
+++ b/src/main/java/me/indian/util/Main.java
@@ -97,9 +97,10 @@ public static void downloadFileTest() throws IOException {
 
         final DownloadListener downloadListener = new DownloadListener() {
             @Override
-            public void onStart(final int definedBuffer, final File outputFile) {
+            public void onStart(final DownloadBuffer downloadBuffer, final int definedBuffer, final File outputFile) {
                 LOGGER.info("Pobieranie:&a " + outputFile.getName());
                 LOGGER.info("Ustalony buffer dla naszego pliku to:&a " + DownloadBuffer.defineBuffer(definedBuffer));
+                LOGGER.info("Domyślny buffer to:&a " + downloadBuffer);
             }
 
             @Override
@@ -113,7 +114,7 @@ public void onProgress(final int progress, final double formatedSpeed, final Str
             }
 
             @Override
-            public void onTimeout(int timeOutSeconds) {
+            public void onTimeout(final int timeOutSeconds) {
                 LOGGER.info("TimeOut");
             }
 
diff --git a/src/main/java/me/indian/util/download/DownloadBuffer.java b/src/main/java/me/indian/util/download/DownloadBuffer.java
index 34d1069..0e61ce6 100644
--- a/src/main/java/me/indian/util/download/DownloadBuffer.java
+++ b/src/main/java/me/indian/util/download/DownloadBuffer.java
@@ -31,10 +31,19 @@ public int getBuffer() {
     }
 
     public static DownloadBuffer defineBuffer(final int buffer) {
-        for (final DownloadBuffer downloadBuffer : values()) {
-            if (downloadBuffer.getBuffer() == buffer) return downloadBuffer;
+        DownloadBuffer closestBuffer = DownloadBuffer.DYNAMIC;
+        int minDifference = Integer.MAX_VALUE;
+
+        for (final DownloadBuffer downloadBuffer : DownloadBuffer.values()) {
+            final int currentBufferSize = downloadBuffer.getBuffer();
+            final int difference = Math.abs(currentBufferSize - buffer);
+
+            if (difference < minDifference) {
+                minDifference = difference;
+                closestBuffer = downloadBuffer;
+            }
         }
 
-        return DYNAMIC;
+        return closestBuffer;
     }
 }
\ No newline at end of file
diff --git a/src/main/java/me/indian/util/download/DownloadListener.java b/src/main/java/me/indian/util/download/DownloadListener.java
index f3c0b11..f7391d5 100644
--- a/src/main/java/me/indian/util/download/DownloadListener.java
+++ b/src/main/java/me/indian/util/download/DownloadListener.java
@@ -4,7 +4,7 @@
 
 public interface DownloadListener {
 
-    void onStart(int definedBuffer, File outputFile);
+    void onStart(DownloadBuffer downloadBuffer, int definedBuffer, File outputFile);
 
     void onSecond(int progress, double formatedSpeed, String remainingTimeString);
 
diff --git a/src/main/java/me/indian/util/download/Downloader.java b/src/main/java/me/indian/util/download/Downloader.java
index 5b44611..4d8c841 100644
--- a/src/main/java/me/indian/util/download/Downloader.java
+++ b/src/main/java/me/indian/util/download/Downloader.java
@@ -24,10 +24,10 @@ public static void downloadFile(final InputStream inputStream, final File output
         long lastActivityTime;
 
         try (final FileOutputStream fileOutputStream = new FileOutputStream(outputFile)) {
-            final int definedBuffer = defineBuffer(downloadBuffer);
+            final int definedBuffer = defineBuffer(downloadBuffer, fileSize);
             final byte[] buffer = new byte[definedBuffer];
 
-            if (downloadListener != null) downloadListener.onStart(definedBuffer, outputFile);
+            if (downloadListener != null) downloadListener.onStart(downloadBuffer, definedBuffer, outputFile);
 
             int bytesRead;
             long totalBytesRead = 0;
@@ -79,21 +79,24 @@ public static void downloadFile(final InputStream inputStream, final File output
         }
     }
 
-    private static int defineBuffer(final DownloadBuffer downloadBuffer) {
-        if (downloadBuffer == DownloadBuffer.DYNAMIC) return calculateOptimalBufferSize();
+    private static int defineBuffer(final DownloadBuffer downloadBuffer, final long fileSize) {
+        if (downloadBuffer == DownloadBuffer.DYNAMIC) return calculateOptimalBufferSize(fileSize);
 
         return downloadBuffer.getBuffer();
     }
 
-    private static int calculateOptimalBufferSize() {
+    private static int calculateOptimalBufferSize(final long fileSize) {
+        final int maxBufferSize = DownloadBuffer.SIXTEEN_MB.getBuffer();
+        final long calculatedBufferSize = (long) (fileSize *  0.1);
         final long bufferPerRequest = ((OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean()).getFreeMemorySize() / 5;
+        final long bufferSize = Math.min(calculatedBufferSize, bufferPerRequest);
 
-        if (bufferPerRequest > DownloadBuffer.SIXTEEN_MB.getBuffer()) {
-            return DownloadBuffer.SIXTEEN_MB.getBuffer();
-        } else if (bufferPerRequest < DownloadBuffer.ONE_MB.getBuffer()) {
+        if (bufferSize > maxBufferSize) {
+            return maxBufferSize;
+        } else if (bufferSize < DownloadBuffer.ONE_MB.getBuffer()) {
             return DownloadBuffer.ONE_MB.getBuffer();
         }
 
-        return (int) bufferPerRequest;
+        return (int) bufferSize;
     }
-}
+}
\ No newline at end of file