diff --git a/src/tribler/core/libtorrent/download_manager/download_state.py b/src/tribler/core/libtorrent/download_manager/download_state.py
index 655a1d977e..e618521a43 100644
--- a/src/tribler/core/libtorrent/download_manager/download_state.py
+++ b/src/tribler/core/libtorrent/download_manager/download_state.py
@@ -6,7 +6,6 @@
 from __future__ import annotations
 
 import logging
-import math
 from enum import Enum
 from typing import TYPE_CHECKING
 
@@ -214,7 +213,8 @@ def get_all_time_ratio(self) -> float:
             return 0
 
         if not self.all_time_download:
-            return 0 if not self.all_time_upload else math.inf
+            # We're returning -1 instead of infinity, as it avoids issues when JSON encoding.
+            return 0 if not self.all_time_upload else -1
 
         return self.all_time_upload / self.all_time_download
 
diff --git a/src/tribler/test_unit/core/libtorrent/download_manager/test_download_state.py b/src/tribler/test_unit/core/libtorrent/download_manager/test_download_state.py
index 9096a177c2..bcf6e49ec2 100644
--- a/src/tribler/test_unit/core/libtorrent/download_manager/test_download_state.py
+++ b/src/tribler/test_unit/core/libtorrent/download_manager/test_download_state.py
@@ -116,7 +116,7 @@ def test_all_time_ratio_no_all_time_download_inf(self) -> None:
         """
         state = DownloadState(Mock(), Mock(all_time_upload=200, all_time_download=0), None)
 
-        self.assertEqual(math.inf, state.get_all_time_ratio())
+        self.assertEqual(-1, state.get_all_time_ratio())
 
     def test_get_files_completion(self) -> None:
         """
diff --git a/src/tribler/ui/src/pages/Downloads/Details.tsx b/src/tribler/ui/src/pages/Downloads/Details.tsx
index ca5b6649ab..7f4c156262 100644
--- a/src/tribler/ui/src/pages/Downloads/Details.tsx
+++ b/src/tribler/ui/src/pages/Downloads/Details.tsx
@@ -68,7 +68,12 @@ export default function DownloadDetails({ selectedDownloads }: { selectedDownloa
                         </div>
                         <div className="flex flex-row">
                             <div className="basis-1/4">{t('Ratio')}</div>
-                            <div className="basis-3/4">{download?.all_time_ratio.toFixed(2)} ({formatBytes(download?.all_time_upload)} upload; {formatBytes(download?.all_time_download)} dowload)</div>
+                            <div className="basis-3/4">{
+                                download.all_time_ratio < 0 ?
+                                    String(`∞`) :
+                                    download?.all_time_ratio.toFixed(2)}
+                                &nbsp;({formatBytes(download?.all_time_upload)} upload; {formatBytes(download?.all_time_download)} dowload)
+                            </div>
                         </div>
                         <div className="flex flex-row">
                             <div className="basis-1/4">{t('Availability')}</div>