diff --git a/crates/feed/src/patreon.rs b/crates/feed/src/patreon.rs
index 4dbc5a9..0436b25 100644
--- a/crates/feed/src/patreon.rs
+++ b/crates/feed/src/patreon.rs
@@ -22,13 +22,17 @@ pub fn is_patreon_creator(url: &str) -> bool {
     matches!(patreon_parts(url), Some((_, None)))
 }
 
-/// Whether two URLs are the same feed. One Patreon show has several spellings -- by the
-/// creator's name, by number, or with no creator at all -- and the token and show are what
-/// identify it.
+/// Whether two URLs are the same feed. The same address over http and https is one feed:
+/// oldvcr's blog was subscribed under both, every post twice (#362). One Patreon show has several
+/// spellings -- by the creator's name, by number, or with no creator at all -- and the token and
+/// show are what identify it.
 #[must_use]
 pub fn same_feed(a: &str, b: &str) -> bool {
-    // Parsing both is the slow part, and only Patreon's addresses can differ and still match.
-    a == b
+    fn bare(u: &str) -> &str {
+        u.strip_prefix("https://").or_else(|| u.strip_prefix("http://")).unwrap_or(u)
+    }
+    // Parsing both is the slow part, and only Patreon's addresses can differ further and still match.
+    bare(a) == bare(b)
         || (a.contains("patreon.com")
             && b.contains("patreon.com")
             && patreon_parts(a).is_some_and(|p| Some(p) == patreon_parts(b)))
@@ -117,6 +121,13 @@ mod tests {
         assert!(!is_patreon_creator(&format!("https://www.patreon.com/rss/x?auth={tok}&show=1")), "one show is a feed");
         assert!(!is_patreon_creator(&format!("https://example.com/rss?auth={tok}")));
 
+        assert!(same_feed(
+            "http://oldvcr.blogspot.com/feeds/posts/default",
+            "https://oldvcr.blogspot.com/feeds/posts/default"
+        ));
+        assert!(!same_feed("https://a.example/feed", "https://b.example/feed"));
+        assert!(!same_feed("https://a.example/feed", "https://a.example/feed/comments"));
+
         // The show you already have by name is the one a bare token would add by number.
         assert!(same_feed(
             &format!("https://www.patreon.com/rss/glasscannon?auth={tok}&show=2073588"),
diff --git a/crates/ipx/CHANGELOG.md b/crates/ipx/CHANGELOG.md
index 17eb019..a8c18ea 100644
--- a/crates/ipx/CHANGELOG.md
+++ b/crates/ipx/CHANGELOG.md
@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- A feed you already have, added again by the same address over http rather than https or the other way round, is the one you have, not a second subscription with every item twice. Changing a feed's address to another feed's over the other scheme is refused the same way (#362).
 - A podcast that was once in an OPML and is now a feed of its own is no longer hidden from All Subscriptions when that OPML is, so its unread items are listed there as the feed list counts them (#358).
 
 ## [1.5.1] - 2026-10-24
diff --git a/crates/ipx/src/catalogue.rs b/crates/ipx/src/catalogue.rs
index ed19177..c63dca7 100644
--- a/crates/ipx/src/catalogue.rs
+++ b/crates/ipx/src/catalogue.rs
@@ -611,6 +611,19 @@ mod tests {
         assert!(ctx.db.feed_summary("has-file").await.unwrap().orphaned, "and flagged as orphaned");
     }
 
+    #[tokio::test]
+    async fn a_feed_added_again_over_the_other_scheme_is_the_one_already_there() {
+        // oldvcr's blog, subscribed over https and again over http: every post twice (#362).
+        let mut cfg = config::Config::default();
+        let mut f = feed();
+        f.url = "https://oldvcr.blogspot.com/feeds/posts/default".into();
+        cfg.feeds.insert("oldvcr".into(), f);
+        let ctx = test_ctx(cfg).await;
+        let got = add_to_catalogue(&ctx, "http://oldvcr.blogspot.com/feeds/posts/default", None, vec![]).await.unwrap();
+        assert_eq!(got, ("oldvcr".to_owned(), true));
+        assert_eq!(ctx.cfg().feeds.len(), 1);
+    }
+
     #[tokio::test]
     async fn a_show_made_a_feed_of_its_own_is_not_hidden_with_its_list() {
         // Unsung: promoted out of a Hacker News OPML hidden from All Subscriptions, its unread
diff --git a/crates/ipx/src/web.rs b/crates/ipx/src/web.rs
index 9cc0980..129a656 100644
--- a/crates/ipx/src/web.rs
+++ b/crates/ipx/src/web.rs
@@ -1238,7 +1238,7 @@ fn check_url(url: &str, id: &str, feeds: &BTreeMap<String, crate::config::Feed>)
         Ok(u) => return Err(format!("{:?} is not an http(s) URL", u.scheme())),
         Err(e) => return Err(format!("that is not a valid URL: {e}")),
     }
-    if let Some((other, _)) = feeds.iter().find(|(k, f)| k.as_str() != id && f.url == url) {
+    if let Some((other, _)) = feeds.iter().find(|(k, f)| k.as_str() != id && crate::feed::same_feed(&f.url, url)) {
         return Err(format!("{other:?} is already subscribed to that URL"));
     }
     Ok(url.to_owned())