diff --git a/Cargo.lock b/Cargo.lock
index 00e9c03..7b442c7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1077,7 +1077,7 @@ dependencies = [
 
 [[package]]
 name = "fsrs"
-version = "1.4.4"
+version = "1.4.5"
 dependencies = [
  "burn",
  "chrono",
diff --git a/Cargo.toml b/Cargo.toml
index fcb20e9..f006891 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "fsrs"
-version = "1.4.4"
+version = "1.4.5"
 authors = ["Open Spaced Repetition"]
 categories = ["algorithms", "science"]
 edition = "2021"
diff --git a/src/optimal_retention.rs b/src/optimal_retention.rs
index 5de3007..55a2cc5 100644
--- a/src/optimal_retention.rs
+++ b/src/optimal_retention.rs
@@ -82,8 +82,11 @@ fn stability_after_success(w: &[f32], s: f32, r: f32, d: f32, rating: usize) ->
 }
 
 fn stability_after_failure(w: &[f32], s: f32, r: f32, d: f32) -> f32 {
-    (w[11] * d.powf(-w[12]) * ((s + 1.0).powf(w[13]) - 1.0) * f32::exp((1.0 - r) * w[14]))
-        .clamp(S_MIN, s / (w[17] * w[18]).exp())
+    let new_s_min = s / (w[17] * w[18]).exp();
+    let new_s =
+        (w[11] * d.powf(-w[12]) * ((s + 1.0).powf(w[13]) - 1.0) * f32::exp((1.0 - r) * w[14]))
+            .min(new_s_min);
+    new_s.clamp(S_MIN, S_MAX)
 }
 
 fn stability_short_term(w: &[f32], s: f32, rating_offset: f32, session_len: f32) -> f32 {