diff --git a/app.py b/app.py
index a033213..92408e0 100644
--- a/app.py
+++ b/app.py
@@ -1248,7 +1248,7 @@ def favicon():
 @app.route("/")
 def main_page():
     now = datetime.now(timezone.utc)
-    month_str = request.args.get("m") or now.strftime("%Y-%m")
+    month_str = request.args.get("month") or now.strftime("%Y-%m")
     start = end = None
 
     if month_str:
diff --git a/templates/main.html b/templates/main.html
index 02ddfb1..1f7fed3 100644
--- a/templates/main.html
+++ b/templates/main.html
@@ -33,7 +33,7 @@
 
 {% set month_names = ["styczeń", "luty", "marzec", "kwiecień", "maj", "czerwiec", "lipiec", "sierpień", "wrzesień",
 "październik", "listopad", "grudzień"] %}
-{% set selected_month = request.args.get('m') or now.strftime('%Y-%m') %}
+{% set selected_month = request.args.get('month') or now.strftime('%Y-%m') %}
 
 <!-- Pulpit: zwykły <select> -->
 <div class="d-none d-md-flex justify-content-end align-items-center flex-wrap gap-2 mb-3">
@@ -230,7 +230,7 @@
           {% for offset in range(0, 6) %}
           {% set d = (now - timedelta(days=offset * 30)) %}
           {% set val = d.strftime('%Y-%m') %}
-          <a href="{{ url_for('main_page', m=val) }}" class="btn btn-outline-light">
+          <a href="{{ url_for('main_page', month=val) }}" class="btn btn-outline-light">
             {{ month_names[d.month - 1] }} {{ d.year }}
           </a>
           {% endfor %}