diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java
index e7a7610a9d..84f7b5c8e6 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientCodec.java
@@ -94,6 +94,17 @@ public final class HttpClientCodec
         this.failOnMissingResponse = failOnMissingResponse;
     }
 
+    /**
+     * Creates a new instance with the specified decoder options.
+     */
+    public HttpClientCodec(
+            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean failOnMissingResponse,
+            boolean validateHeaders, int initialBufferSize) {
+        init(new Decoder(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders, initialBufferSize),
+             new Encoder());
+        this.failOnMissingResponse = failOnMissingResponse;
+    }
+
     private final class Encoder extends HttpRequestEncoder {
 
         @Override
@@ -120,6 +131,11 @@ public final class HttpClientCodec
             super(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders);
         }
 
+        Decoder(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean validateHeaders,
+                int initialBufferSize) {
+            super(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders, initialBufferSize);
+        }
+
         @Override
         protected void decode(
                 ChannelHandlerContext ctx, ByteBuf buffer, List<Object> out) throws Exception {
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
index 063f220edd..d2a662bbd7 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
@@ -162,7 +162,12 @@ public abstract class HttpObjectDecoder extends ByteToMessageDecoder {
     protected HttpObjectDecoder(
             int maxInitialLineLength, int maxHeaderSize, int maxChunkSize,
             boolean chunkedSupported, boolean validateHeaders) {
+        this(maxInitialLineLength, maxHeaderSize, maxChunkSize, chunkedSupported, validateHeaders, 128);
+    }
 
+    protected HttpObjectDecoder(
+            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize,
+            boolean chunkedSupported, boolean validateHeaders, int initialBufferSize) {
         if (maxInitialLineLength <= 0) {
             throw new IllegalArgumentException(
                     "maxInitialLineLength must be a positive integer: " +
@@ -178,12 +183,12 @@ public abstract class HttpObjectDecoder extends ByteToMessageDecoder {
                     "maxChunkSize must be a positive integer: " +
                             maxChunkSize);
         }
+        AppendableCharSequence seq = new AppendableCharSequence(initialBufferSize);
+        lineParser = new LineParser(seq, maxInitialLineLength);
+        headerParser = new HeaderParser(seq, maxHeaderSize);
         this.maxChunkSize = maxChunkSize;
         this.chunkedSupported = chunkedSupported;
         this.validateHeaders = validateHeaders;
-        AppendableCharSequence seq = new AppendableCharSequence(128);
-        lineParser = new LineParser(seq, maxInitialLineLength);
-        headerParser = new HeaderParser(seq, maxHeaderSize);
     }
 
     @Override
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestDecoder.java
index 91364a9cf3..0fd2d02914 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestDecoder.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestDecoder.java
@@ -76,6 +76,12 @@ public class HttpRequestDecoder extends HttpObjectDecoder {
         super(maxInitialLineLength, maxHeaderSize, maxChunkSize, true, validateHeaders);
     }
 
+    public HttpRequestDecoder(
+            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean validateHeaders,
+            int initialBufferSize) {
+        super(maxInitialLineLength, maxHeaderSize, maxChunkSize, true, validateHeaders, initialBufferSize);
+    }
+
     @Override
     protected HttpMessage createMessage(String[] initialLine) throws Exception {
         return new DefaultHttpRequest(
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpResponseDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpResponseDecoder.java
index 485d0a26e3..17043ff3e7 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpResponseDecoder.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpResponseDecoder.java
@@ -107,6 +107,12 @@ public class HttpResponseDecoder extends HttpObjectDecoder {
         super(maxInitialLineLength, maxHeaderSize, maxChunkSize, true, validateHeaders);
     }
 
+    public HttpResponseDecoder(
+            int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean validateHeaders,
+            int initialBufferSize) {
+        super(maxInitialLineLength, maxHeaderSize, maxChunkSize, true, validateHeaders, initialBufferSize);
+    }
+
     @Override
     protected HttpMessage createMessage(String[] initialLine) {
         return new DefaultHttpResponse(
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpServerCodec.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpServerCodec.java
index c10185a51b..98e95bfee7 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpServerCodec.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpServerCodec.java
@@ -50,4 +50,14 @@ public final class HttpServerCodec
         super(new HttpRequestDecoder(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders),
                 new HttpResponseEncoder());
     }
+
+    /**
+     * Creates a new instance with the specified decoder options.
+     */
+    public HttpServerCodec(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean validateHeaders,
+                           int initialBufferSize) {
+        super(
+          new HttpRequestDecoder(maxInitialLineLength, maxHeaderSize, maxChunkSize, validateHeaders, initialBufferSize),
+          new HttpResponseEncoder());
+    }
 }