diff --git a/codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionDecoder.java b/codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionDecoder.java
index c47b83a9fd..7cd935269b 100644
--- a/codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionDecoder.java
+++ b/codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionDecoder.java
@@ -149,8 +149,7 @@ public class DefaultHttp2ConnectionDecoder implements Http2ConnectionDecoder {
      * @return the threshold in bytes which should trigger a {@code GO_AWAY} if a set of headers exceeds this amount.
      */
     protected long calculateMaxHeaderListSizeGoAway(long maxHeaderListSize) {
-        // This is equivalent to `maxHeaderListSize * 1.25` but we avoid floating point multiplication.
-        return maxHeaderListSize + (maxHeaderListSize >>> 2);
+        return Http2CodecUtil.calculateMaxHeaderListSizeGoAway(maxHeaderListSize);
     }
 
     private int unconsumedBytes(Http2Stream stream) {
diff --git a/codec-http2/src/main/java/io/netty/handler/codec/http2/Http2CodecUtil.java b/codec-http2/src/main/java/io/netty/handler/codec/http2/Http2CodecUtil.java
index 4b2860cd53..0de81ecaed 100644
--- a/codec-http2/src/main/java/io/netty/handler/codec/http2/Http2CodecUtil.java
+++ b/codec-http2/src/main/java/io/netty/handler/codec/http2/Http2CodecUtil.java
@@ -112,6 +112,18 @@ public final class Http2CodecUtil {
     public static final long DEFAULT_HEADER_LIST_SIZE = 8192;
     public static final int DEFAULT_MAX_FRAME_SIZE = MAX_FRAME_SIZE_LOWER_BOUND;
 
+    /**
+     * Calculate the threshold in bytes which should trigger a {@code GO_AWAY} if a set of headers exceeds this amount.
+     * @param maxHeaderListSize
+     *      <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a> for the local
+     *      endpoint.
+     * @return the threshold in bytes which should trigger a {@code GO_AWAY} if a set of headers exceeds this amount.
+     */
+    public static long calculateMaxHeaderListSizeGoAway(long maxHeaderListSize) {
+        // This is equivalent to `maxHeaderListSize * 1.25` but we avoid floating point multiplication.
+        return maxHeaderListSize + (maxHeaderListSize >>> 2);
+    }
+
     /**
      * Returns {@code true} if the stream is an outbound stream.
      *
diff --git a/codec-http2/src/main/java/io/netty/handler/codec/http2/internal/hpack/Decoder.java b/codec-http2/src/main/java/io/netty/handler/codec/http2/internal/hpack/Decoder.java
index 045c66c6a1..3e8c8f8050 100644
--- a/codec-http2/src/main/java/io/netty/handler/codec/http2/internal/hpack/Decoder.java
+++ b/codec-http2/src/main/java/io/netty/handler/codec/http2/internal/hpack/Decoder.java
@@ -32,6 +32,7 @@
 package io.netty.handler.codec.http2.internal.hpack;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.handler.codec.http2.Http2CodecUtil;
 import io.netty.handler.codec.http2.Http2Exception;
 import io.netty.handler.codec.http2.Http2Headers;
 import io.netty.handler.codec.http2.internal.hpack.HpackUtil.IndexType;
@@ -106,7 +107,9 @@ public final class Decoder {
      * for testing but violate the RFC if used outside the scope of testing.
      */
     Decoder(long maxHeaderListSize, int initialHuffmanDecodeCapacity, int maxHeaderTableSize) {
-        this.maxHeaderListSize = maxHeaderListSizeGoAway = checkPositive(maxHeaderListSize, "maxHeaderListSize");
+        this.maxHeaderListSize = checkPositive(maxHeaderListSize, "maxHeaderListSize");
+        this.maxHeaderListSizeGoAway = Http2CodecUtil.calculateMaxHeaderListSizeGoAway(maxHeaderListSize);
+
         maxDynamicTableSize = encoderMaxDynamicTableSize = maxHeaderTableSize;
         maxDynamicTableSizeChangeRequired = false;
         dynamicTable = new DynamicTable(maxHeaderTableSize);
diff --git a/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2HeadersDecoderTest.java b/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2HeadersDecoderTest.java
index b6a6a3dd1b..efa52ab22c 100644
--- a/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2HeadersDecoderTest.java
+++ b/codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2HeadersDecoderTest.java
@@ -84,6 +84,21 @@ public class DefaultHttp2HeadersDecoderTest {
         }
     }
 
+    @Test
+    public void decodeLargerThanHeaderListSizeButLessThanGoAwayWithInitialDecoderSettings() throws Exception {
+        ByteBuf buf = encode(b(":method"), b("GET"), b("test_header"),
+            b(String.format("%09000d", 0).replace('0', 'A')));
+        final int streamId = 1;
+        try {
+            decoder.decodeHeaders(streamId, buf);
+            fail();
+        } catch (Http2Exception.HeaderListSizeException e) {
+            assertEquals(streamId, e.streamId());
+        } finally {
+            buf.release();
+        }
+    }
+
     @Test
     public void decodeLargerThanHeaderListSizeGoAway() throws Exception {
         decoder.maxHeaderListSize(MIN_HEADER_LIST_SIZE, MIN_HEADER_LIST_SIZE);