diff --git a/src/mlp.c b/src/mlp.c
index 0e5ef16b..f43a704e 100644
--- a/src/mlp.c
+++ b/src/mlp.c
@@ -66,7 +66,7 @@ static OPUS_INLINE float tansig_approx(float x)
 
 static OPUS_INLINE float sigmoid_approx(float x)
 {
-   return .5 + .5*tansig_approx(.5*x);
+   return .5f + .5f*tansig_approx(.5f*x);
 }
 
 void compute_dense(const DenseLayer *layer, float *output, const float *input)