diff --git a/app/assets/javascripts/discourse/app/mixins/uppy-s3-multipart.js b/app/assets/javascripts/discourse/app/mixins/uppy-s3-multipart.js
index 0de515d2a79..5c905dd3e9e 100644
--- a/app/assets/javascripts/discourse/app/mixins/uppy-s3-multipart.js
+++ b/app/assets/javascripts/discourse/app/mixins/uppy-s3-multipart.js
@@ -5,6 +5,7 @@ import { Promise } from "rsvp";
 import { ajax } from "discourse/lib/ajax";
 import AwsS3Multipart from "@uppy/aws-s3-multipart";
 const RETRY_DELAYS = [0, 1000, 3000, 5000];
+const MB = 1024 * 1024;
 
 export default Mixin.create({
   _useS3MultipartUploads() {
@@ -21,6 +22,20 @@ export default Mixin.create({
       limit: 10,
       retryDelays: RETRY_DELAYS,
 
+      // When we get to really big files, it's better to not have thousands
+      // of small chunks, since we don't have a resume functionality if the
+      // upload fails. Better to try upload less chunks even if those chunks
+      // are bigger.
+      getChunkSize(file) {
+        if (file.size >= 500 * MB) {
+          return 20 * MB;
+        } else if (file.size >= 100 * MB) {
+          return 10 * MB;
+        } else {
+          return 5 * MB;
+        }
+      },
+
       createMultipartUpload: this._createMultipartUpload,
       prepareUploadParts: this._prepareUploadParts,
       completeMultipartUpload: this._completeMultipartUpload,