diff --git a/README.md b/README.md
index 163e77c..cf2155f 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,6 @@
 Tiny cypress command to upload fast large files to an HTML input type="file".
 The file that will be uploaded is empty. Multiple attribute is not supported {yet}.
 
-
 # Installation
 ```bash
 npm i dummyattachfile
@@ -19,7 +18,10 @@ import 'dummyattachfile';
 ```javascript
 cy.get('input').dummyAttachFile(<bytes>, <filename>, <filetype>)
 
-// <bytes>    Number | Optional | Default value: 1024   
+// <bytes>    Number or String | Optional | Default value: 1024
+// Number expressed in bytes
+// Valid String Format: d+K, d+M eg. 666K, 500M etc.
+// Current file limit: 1GB
 // <filename> String | Optional | Default value: 'whatever.txt'
 // <filetype> String | Optional | Default value: 'text/plain'
 
diff --git a/package.json b/package.json
index 21c788b..bb2ef61 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "dummyattachfile",
-  "version": "0.0.12",
+  "version": "0.0.13",
   "description": "dummy uploading a file for cypress tests",
   "main": "dist/bundle.js",
   "source": "src/index.js",
diff --git a/src/main.js b/src/main.js
index 4f033ab..15cd30a 100644
--- a/src/main.js
+++ b/src/main.js
@@ -1,13 +1,49 @@
 export default function dummyAttachFile(subject, sizeBytes = 1024, fileName = 'whatever.txt', fileType = 'text/plain') {
 
+    // if bytes do not respect the FILE_LIMIT
+    // force it to FILE_LIMIT
+    const FILE_LIMIT = 1047527424
+
     // if arguments do not respect their type
     // convert them to defaults
+
     if (typeof sizeBytes !== 'number') {
+        if (typeof sizeBytes === 'string') {
+        const re = /^\d+[MK]{1}$/
+        if (re.test(sizeBytes)) {
+            const MB = sizeBytes.charAt(sizeBytes.length-1)
+            const parsed = parseInt(sizeBytes.substring(0, sizeBytes.length-1), 10)
+            // is it possible isNaN to be true??
+            // since regexp has handled the format?
+            if (isNaN(parsed)){
+            sizeBytes = 1024
+            }
+            else {
+            // 'K' Kilobytes case
+            sizeBytes = parsed*1024
+            // 'M' Megabytes case
+            if ( MB === 'M') {
+                sizeBytes *= 1024
+            }
+
+            }
+        } else {
+            sizeBytes = 1024
+        }
+        }
+        else {
         sizeBytes = 1024
+        }
     }
+
+    if (sizeBytes > FILE_LIMIT) {
+        sizeBytes = FILE_LIMIT
+    }
+
     if (typeof fileName !== 'string') {
         fileName = 'whatever.txt'
     }
+
     if (typeof fileType !== 'string') {
         fileType = 'text/plain'
     }