diff --git a/Sources/Hummingbird/Codable/JSON/JSONCoding.swift b/Sources/Hummingbird/Codable/JSON/JSONCoding.swift
index 48af13b3e..a58ae24a1 100644
--- a/Sources/Hummingbird/Codable/JSON/JSONCoding.swift
+++ b/Sources/Hummingbird/Codable/JSON/JSONCoding.swift
@@ -30,7 +30,7 @@ extension JSONEncoder: ResponseEncoder {
             status: .ok,
             headers: [
                 .contentType: "application/json; charset=utf-8",
-                .contentLength: String(describing: data.count),
+                .contentLength: data.count.description,
             ],
             body: .init(byteBuffer: buffer)
         )
diff --git a/Sources/Hummingbird/Codable/URLEncodedForm/URLEncodedForm+Request.swift b/Sources/Hummingbird/Codable/URLEncodedForm/URLEncodedForm+Request.swift
index 2ab62afe3..cf3425c31 100644
--- a/Sources/Hummingbird/Codable/URLEncodedForm/URLEncodedForm+Request.swift
+++ b/Sources/Hummingbird/Codable/URLEncodedForm/URLEncodedForm+Request.swift
@@ -23,7 +23,10 @@ extension URLEncodedFormEncoder: ResponseEncoder {
         buffer.writeString(string)
         return Response(
             status: .ok,
-            headers: [.contentType: "application/x-www-form-urlencoded"],
+            headers: [
+                .contentType: "application/x-www-form-urlencoded",
+                .contentLength: buffer.readableBytes.description,
+            ],
             body: .init(byteBuffer: buffer)
         )
     }
diff --git a/Sources/Hummingbird/Router/ResponseGenerator.swift b/Sources/Hummingbird/Router/ResponseGenerator.swift
index 1d3268709..54df093f2 100644
--- a/Sources/Hummingbird/Router/ResponseGenerator.swift
+++ b/Sources/Hummingbird/Router/ResponseGenerator.swift
@@ -33,7 +33,14 @@ extension String: ResponseGenerator {
     /// Generate response holding string
     public func response(from request: Request, context: some BaseRequestContext) -> Response {
         let buffer = context.allocator.buffer(string: self)
-        return Response(status: .ok, headers: [.contentType: "text/plain; charset=utf-8"], body: .init(byteBuffer: buffer))
+        return Response(
+            status: .ok,
+            headers: [
+                .contentType: "text/plain; charset=utf-8",
+                .contentLength: buffer.readableBytes.description,
+            ],
+            body: .init(byteBuffer: buffer)
+        )
     }
 }
 
@@ -42,7 +49,14 @@ extension Substring: ResponseGenerator {
     /// Generate response holding string
     public func response(from request: Request, context: some BaseRequestContext) -> Response {
         let buffer = context.allocator.buffer(substring: self)
-        return Response(status: .ok, headers: [.contentType: "text/plain; charset=utf-8"], body: .init(byteBuffer: buffer))
+        return Response(
+            status: .ok,
+            headers: [
+                .contentType: "text/plain; charset=utf-8",
+                .contentLength: buffer.readableBytes.description,
+            ],
+            body: .init(byteBuffer: buffer)
+        )
     }
 }
 
@@ -50,7 +64,14 @@ extension Substring: ResponseGenerator {
 extension ByteBuffer: ResponseGenerator {
     /// Generate response holding bytebuffer
     public func response(from request: Request, context: some BaseRequestContext) -> Response {
-        Response(status: .ok, headers: [.contentType: "application/octet-stream"], body: .init(byteBuffer: self))
+        Response(
+            status: .ok,
+            headers: [
+                .contentType: "application/octet-stream",
+                .contentLength: self.readableBytes.description,
+            ],
+            body: .init(byteBuffer: self)
+        )
     }
 }
 
diff --git a/Sources/HummingbirdCore/Response/Response.swift b/Sources/HummingbirdCore/Response/Response.swift
index 71eda27a8..0314f32cf 100644
--- a/Sources/HummingbirdCore/Response/Response.swift
+++ b/Sources/HummingbirdCore/Response/Response.swift
@@ -28,7 +28,7 @@ public struct Response: Sendable {
     public init(status: HTTPResponse.Status, headers: HTTPFields = .init(), body: ResponseBody = .init()) {
         self.head = .init(status: status, headerFields: headers)
         self.body = body
-        if let contentLength = body.contentLength, headers[.contentLength] == nil {
+        if let contentLength = body.contentLength, headers[values: .contentLength].count == 0 {
             self.head.headerFields[.contentLength] = String(describing: contentLength)
         }
     }