diff --git a/particles/ramp.c b/particles/ramp.c
index 987ff64..868d854 100644
--- a/particles/ramp.c
+++ b/particles/ramp.c
@@ -107,7 +107,7 @@ instantiate(const struct particle *particle, const struct tag_set *tags)
 
     size_t idx = 0;
     if (max - min > 0)
-        idx = p->count * value / (max - min);
+        idx = p->count * (value - min) / (max - min);
 
     if (idx == p->count)
         idx--;