diff --git a/spring-core/src/main/java/org/springframework/core/codec/ResourceDecoder.java b/spring-core/src/main/java/org/springframework/core/codec/ResourceDecoder.java
index eeb307cfcdf..4e9552a650a 100644
--- a/spring-core/src/main/java/org/springframework/core/codec/ResourceDecoder.java
+++ b/spring-core/src/main/java/org/springframework/core/codec/ResourceDecoder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -83,6 +83,10 @@ public class ResourceDecoder extends AbstractDataBufferDecoder<Resource> {
 				public String getFilename() {
 					return filename;
 				}
+				@Override
+				public long contentLength() {
+					return bytes.length;
+				}
 			};
 		}
 		else if (Resource.class.isAssignableFrom(clazz)) {
diff --git a/spring-core/src/test/java/org/springframework/core/codec/ResourceDecoderTests.java b/spring-core/src/test/java/org/springframework/core/codec/ResourceDecoderTests.java
index 1c3a531f7a3..f060ce4f359 100644
--- a/spring-core/src/test/java/org/springframework/core/codec/ResourceDecoderTests.java
+++ b/spring-core/src/test/java/org/springframework/core/codec/ResourceDecoderTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -82,10 +82,7 @@ class ResourceDecoderTests extends AbstractDecoderTests<ResourceDecoder> {
 	@Override
 	@Test
 	public void decodeToMono() {
-		Flux<DataBuffer> input = Flux.concat(
-				dataBuffer(this.fooBytes),
-				dataBuffer(this.barBytes));
-
+		Flux<DataBuffer> input = Flux.concat(dataBuffer(this.fooBytes), dataBuffer(this.barBytes));
 		testDecodeToMonoAll(input, ResolvableType.forClass(Resource.class),
 				step -> step
 						.consumeNextWith(value -> {
@@ -105,4 +102,22 @@ class ResourceDecoderTests extends AbstractDecoderTests<ResourceDecoder> {
 				Collections.singletonMap(ResourceDecoder.FILENAME_HINT, "testFile"));
 	}
 
+	@Test
+	public void decodeInputStreamResource() {
+		Flux<DataBuffer> input = Flux.concat(dataBuffer(this.fooBytes), dataBuffer(this.barBytes));
+		testDecodeAll(input, InputStreamResource.class, step -> step
+				.consumeNextWith(resource -> {
+					try {
+						byte[] bytes = StreamUtils.copyToByteArray(resource.getInputStream());
+						assertThat(new String(bytes)).isEqualTo("foobar");
+						assertThat(resource.contentLength()).isEqualTo(fooBytes.length + barBytes.length);
+					}
+					catch (IOException ex) {
+						throw new AssertionError(ex.getMessage(), ex);
+					}
+				})
+				.expectComplete()
+				.verify());
+	}
+
 }
diff --git a/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
index 582ab859de1..f587aecf7ff 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/ResourceHttpMessageConverter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -84,6 +84,11 @@ public class ResourceHttpMessageConverter extends AbstractHttpMessageConverter<R
 				public String getFilename() {
 					return inputMessage.getHeaders().getContentDisposition().getFilename();
 				}
+				@Override
+				public long contentLength() throws IOException {
+					long length = inputMessage.getHeaders().getContentLength();
+					return (length != -1 ? length : super.contentLength());
+				}
 			};
 		}
 		else if (Resource.class == clazz || ByteArrayResource.class.isAssignableFrom(clazz)) {
diff --git a/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java b/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java
index efc1163bd75..5a05d431c79 100644
--- a/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java
+++ b/spring-web/src/test/java/org/springframework/http/converter/ResourceHttpMessageConverterTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -80,10 +80,12 @@ public class ResourceHttpMessageConverterTests {
 			inputMessage.getHeaders().setContentType(MediaType.IMAGE_JPEG);
 			inputMessage.getHeaders().setContentDisposition(
 					ContentDisposition.builder("attachment").filename("yourlogo.jpg").build());
+			inputMessage.getHeaders().setContentLength(123);
 			Resource actualResource = converter.read(InputStreamResource.class, inputMessage);
 			assertThat(actualResource).isInstanceOf(InputStreamResource.class);
 			assertThat(actualResource.getInputStream()).isEqualTo(body);
 			assertThat(actualResource.getFilename()).isEqualTo("yourlogo.jpg");
+			assertThat(actualResource.contentLength()).isEqualTo(123);
 		}
 	}