diff --git a/borgweb/borg/urls.py b/borgweb/borg/urls.py
index d4a2980..60d3752 100644
--- a/borgweb/borg/urls.py
+++ b/borgweb/borg/urls.py
@@ -8,6 +8,7 @@ urlpatterns = [
     path('repo_daily.json', cache_page(3600)(views.repo_daily_json), name='daily repo json'),
     path('repo_monthly.json', cache_page(3600 * 12)(views.repo_monthly_json), name='monthly repo json'),
     path('repo_list.json', cache_page(60)(views.repo_list_json), name='repo list'),
+    path('repo/<str:repo_label>/size.json', cache_page(60)(views.repo_size_json), name='repo size time series'),
     path('repo/<str:repo_label>.json', cache_page(60)(views.repo_json), name='repo json'),
     path('repo/<str:repo_label>', cache_page(60)(views.repo), name='repo'),
     path('post/repo', views.post_repo, name='post repo'),
diff --git a/borgweb/borg/views/__init__.py b/borgweb/borg/views/__init__.py
index fb30390..82ea75f 100644
--- a/borgweb/borg/views/__init__.py
+++ b/borgweb/borg/views/__init__.py
@@ -1,3 +1,3 @@
 from .views import index, repo, axes
 from .post import post_repo, post_archive, post_error, post_location
-from .json import repo_daily_json, repo_monthly_json, repo_list_json, repo_json
+from .json import repo_daily_json, repo_monthly_json, repo_list_json, repo_json, repo_size_json
diff --git a/borgweb/borg/views/json.py b/borgweb/borg/views/json.py
index a053c07..8d5ec70 100644
--- a/borgweb/borg/views/json.py
+++ b/borgweb/borg/views/json.py
@@ -17,6 +17,26 @@ def repo_json(request, repo_label):
     return JsonResponse(repo_dict)
 
 
+def repo_size_json(request, repo_label, months_ago: int = 12):
+    repo = get_object_or_404(Repo, label__label=repo_label)
+
+    date_labels = [date.strftime("%b %Y") for date in last_day_previous_months(months_ago)]
+
+    max_unit = get_units([repo])
+
+    repo_dict = {"id": repo.id,
+                 "label": repo.label.label,
+                 "size": repo.size_on_months(max_unit, months_ago)}
+
+    response_dict = {
+        "dates": date_labels,
+        "repo": repo_dict,
+        "units": max_unit
+    }
+
+    return JsonResponse(response_dict)
+
+
 def repo_list_json(request):
     return JsonResponse({'labels': [repo.label.label for repo in Repo.objects.all()]})
 
@@ -70,4 +90,3 @@ def get_units(repo_list):
     max_repo_size = max(repo.latest_archive().cache.unique_csize for repo in repo_list)
     _, max_unit = data.convert_bytes(max_repo_size)
     return max_unit
-