diff --git a/README.md b/README.md
index 895deae..b0a8919 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,8 @@ const initStats = require('@phil-r/stats');
 const { statsMiddleware, getStats } = initStats({
   endpointStats: true,
   complexEndpoints: ['/user/:id'],
-  customStats: true
+  customStats: true,
+  addHeader: true
 });
 ```
 
@@ -63,6 +64,13 @@ function handler(req, res) {
 }
 ```
 
+##### addHeader
+
+Defaults to `false`
+
+Adds `X-Response-Time` header to all responses, can be used to replace
+[`expressjs/response-time`](https://github.com/expressjs/response-time)
+
 ## Full example
 
 Here is the example of usage in express app
@@ -74,7 +82,8 @@ const initStats = require('@phil-r/stats');
 const { statsMiddleware, getStats } = initStats({
   endpointStats: true,
   complexEndpoints: ['/user/:id'],
-  customStats: true
+  customStats: true,
+  addHeader: true
 });
 
 app.use(statsMiddleware);
diff --git a/index.js b/index.js
index 27656cd..33e56b4 100644
--- a/index.js
+++ b/index.js
@@ -73,6 +73,12 @@ function initMiddleware(opts = {}) {
     onHeaders(res, () => {
       const time = hrTimeToMs(process.hrtime(requestStart));
 
+      if (opts.addHeader) {
+        if (!res.getHeader('X-Response-Time')) {
+          res.setHeader('X-Response-Time', `${time.toFixed(0)}ms`);
+        }
+      }
+
       stats.totalTime += time;
       stats.count++;
       stats.averageTime = stats.totalTime / stats.count;