diff --git a/libs/ml/include/psemek/ml/neural_net/activation.hpp b/libs/ml/include/psemek/ml/neural_net/activation.hpp
index 415bd760..6d754b1e 100644
--- a/libs/ml/include/psemek/ml/neural_net/activation.hpp
+++ b/libs/ml/include/psemek/ml/neural_net/activation.hpp
@@ -36,7 +36,7 @@ namespace psemek::ml
 		case activation_type::softplus:
 			return (x < T{0})
 				? std::log(T{1} + std::exp(x))
-				: x + std::log(T{1} + std::exp(-1));
+				: x + std::log(T{1} + std::exp(-x));
 		case activation_type::squareplus:
 			return (x < T{0})
 				? T{2} / (std::sqrt(x * x + T{4}) - x)